CN106326334A - Display method and device for electronic map and generation method and device for electronic map - Google Patents

Abstract

The application discloses a display method for an electronic map, which is used for solving the problems of corresponding relatively-single observation viewing angle and poor flexibility of an electronic map displayed in a client in the prior art. The method comprises: by the client, receiving an electronic map display instruction, wherein in the electronic map display instruction comprises information of an observation viewing angle aiming at a three-dimensional terrain model; by the client, according to the information of the observation viewing angle, acquiring a block set corresponding to the observation viewing angle from a set of the block sets generated by a server; by the client, according to coordinates of blocks in the acquired block set in a world coordinate system, splicing and loading the blocks in the acquired block set to display the electronic map. The application further provides a display device for the electronic map, a generation method for the electronic map and a generation device for the electronic map.

Description

The display of a kind of electronic chart, generation method and apparatus

Technical field

The application relates to electronic map technique field, particularly relates to the display of a kind of electronic chart, generates method and apparatus.

Background technology

Electronic chart is to utilize computer technology, the numerical map storing in a digital manner and consulting, and has generally included 2 dimensions Electronic chart, 3-dimensional electronic chart and 2.5 dimension electronic charts.2 dimension electronic charts are a kind of abstract representations to real world, There is the defects such as spatial information not directly perceived, load is less, the world that reflects reality that can not be the most complete in expression.3-dimensional Electronic chart has efficient, directly perceived, three-dimensional, the feature of intervisibility compared with for 2 dimension electronic charts, can express objective generation more realistically Boundary, and ground object model can be carried out 3-dimensional and show, analyze and operate, but owing to data volume is big, high in cost of production factor, 3-dimensional electronics The range of application of map is also restricted.

For 2 dimension electronic charts and 3-dimensional electronic chart, 2.5 dimension electronic charts had both met current technical conditions, Cater to again the application demand of reality.2.5 dimension electronic charts are the ground object model (claiming dimensionally object model afterwards) that 3-dimensional is three-dimensional to be pressed It is mapped on a certain projection plane according to certain projection rule, to show 2 dimension figures of ground object model 3-dimensional stereoeffect.2.5 dimension Electronic chart is except inheriting powerful at the aspect such as data acquisition, input and output, spatial data analysis and process of 2 dimension electronic charts Outside function, its spatial entities expressive ability natural, true, abundant, compensate for the limitation of 2 dimension electronic chart graphical representation, Avoid that 3-dimensional electronic map data amount is big and high in cost of production problem simultaneously.

At present, for 2.5 dimension electronic charts, it is usually and is used for by electronic map server (abbreviation server) preservation The segment of splicing electronic chart, electronic map client side (abbreviation client) is downloaded segment from server according to demand and utilizes figure Block splicing electronic chart.

From the prior art from the point of view of the electronic chart shown by different clients, the most different electricity shown by client Sub-map, all corresponds to the electronic chart of same observation visual angle.Such as, it is shown that seeing according to certain fixing angle of pitch Examine ground various element (including mountains and rivers, river and building etc.), obtained electronic chart.Such electronic chart shows Showing mode, motility is poor, it is difficult to meet the actual demand of different user.

Summary of the invention

The embodiment of the present application provides the display packing of a kind of electronic chart, for solving what client in prior art showed The observation visual angle that electronic chart is corresponding is more single, the problem that motility is poor.

Further, the embodiment of the present application additionally provides the display device of a kind of electronic chart, is used for solving prior art The observation visual angle that electronic chart that middle client shows is corresponding is more single, the problem that motility is poor.

The embodiment of the present application also provides for one map generalization method and apparatus electronically.

For achieving the above object, the embodiment of the present application provides the display packing of a kind of electronic chart, including: client receives Electronic chart idsplay order；In described electronic chart idsplay order, including the information of the observation visual angle for dimensionally object model； Client, according to the information of described observation visual angle, obtains corresponding to described observation visual angle from the segment collection set that server generates Segment collection；Wherein said segment collection set, corresponds respectively to the segment collection of different observation visual angle including at least two；Single figure The segment that block is concentrated, obtains in dimensionally object model projects to image coordinate system according to same observation visual angle；Client The segment according to the segment concentration got coordinate in world coordinate system, splices and loads the figure that the segment got is concentrated Block is to show electronic chart.

Preferably, in described electronic chart idsplay order, also include the position of viewing area in described world coordinate system Information；The segment that client is concentrated according to the segment that gets coordinate in world coordinate system, splices and loads and get The segment that segment is concentrated, including: client according to the positional information of described viewing area, and described in the segment that gets concentrate Segment coordinate in world coordinate system, from the segment that the described segment collection got comprises, be chosen at world coordinate system In coordinate fall into the segment of described viewing area；Client is according to the segment chosen coordinate in world coordinate system, splicing And load the segment selected.

Preferably, client, according to the segment chosen coordinate in world coordinate system, is spliced and loads the figure selected Block, including: client according to the segment selected coordinate in world coordinate system, the default splicing in described image coordinate system Datum mark coordinate in world coordinate system, and in described image coordinate system, single pixel institute in described world coordinate system is right The geographic distance answered, splices and loads the segment selected.

For achieving the above object, the embodiment of the present application provides one map generalization method electronically, including: server generates The segment collection set that the segment collection of different observation visual angle forms is corresponded respectively to by least two；The segment that single segment is concentrated, Obtain in dimensionally object model projects to image coordinate system according to same observation visual angle；Server is according to world coordinate system In the coordinate of selected reference point, determine that each segment concentrates each segment coordinate in described world coordinate system, as profit The segment concentrated with described segment splices the coordinate of electronic chart time institute foundation.

Preferably, described observation visual angle, including the angle of pitch and/or the anglec of rotation；The described angle of pitch, in camera coordinates system The angle between given plane in camera optical axis and described world coordinate system；Described given plane, for being sat by the described world X-axis in mark system and the plane that determines of Y-axis；Described X-axis, points to the seat in direction, due east for the positive direction in described world coordinate system Parameter；Described Y-axis, points to the coordinate axes of direct north for the positive direction in described world coordinate system；The described anglec of rotation, for described Camera optical axis is relative to the anglec of rotation of the Z axis in described world coordinate system；Described Z axis, for hanging down in described world coordinate system Straight in the coordinate axes of described given plane.

Preferably, described segment, during translating relative to image coordinate system for camera view, take the photograph with described Described in the sensing of camera optical axis, dimensionally the direction of object model is projecting direction, according to the observation visual angle set, uses parallel projection Mode obtain described during dimensionally object model projects to image coordinate system；Described camera view, for camera coordinates system In, the plane that is perpendicular to described camera optical axis.

Preferably, when described observation visual angle includes the angle of pitch, server is according to the selected reference point in world coordinate system Coordinate, determines that each segment concentrates each segment coordinate in described world coordinate system, including: server is for arbitrary segment Perform respectively: sit in the described world according to the initial position that the central point of described camera view is residing in described translation motion When coordinate in mark system, projection described camera view and described given plane in described world coordinate system distance, Described camera view size in described world coordinate system, the described angle of pitch are corresponding with described initial position with this segment Between segment, the segment number at interval, calculates this segment coordinate in described world coordinate system.

Preferably, when described observation visual angle includes the angle of pitch and the anglec of rotation, server is according to described in world coordinate system The coordinate of selected reference point, determines that each segment concentrates each segment coordinate in described world coordinate system, including: server Perform respectively for arbitrary segment: according to the initial position that the central point of described camera view is residing in described translation motion When coordinate in described world coordinate system, projection described camera view with described given plane in described world coordinate system Distance, described camera view size, the described angle of pitch, the described anglec of rotation and this figure in described world coordinate system Between block and segment corresponding to described initial position, the segment number at interval, calculates this segment seat in described world coordinate system Mark.

For achieving the above object, the embodiment of the present application provides the display device of a kind of electronic chart, and described display device should Being used in client, described display device includes: receive unit, segment acquiring unit and splicing loading unit, wherein, described reception Unit, is used for receiving electronic chart idsplay order；In described electronic chart idsplay order, including the sight for dimensionally object model Examine the information at visual angle；Described segment acquiring unit, for the information according to described observation visual angle, the segment collection generated from server Set obtains the segment collection corresponding to described observation visual angle；Wherein, described segment collection set, including at least two correspondence respectively Segment collection in different observation visual angles；The segment that single segment is concentrated, is will dimensionally to throw by object model according to same observation visual angle Shadow is to obtaining in image coordinate system；Described splicing loading unit, is used for the segment according to the segment concentration got in the world Coordinate in coordinate system, splices and loads the segment of the segment concentration got to show electronic chart.

For achieving the above object, the embodiment of the present application provides the generating means of a kind of electronic chart, and described generating means should Being used in server, described generating means includes: segment collection signal generating unit and coordinate determine unit, and wherein, described segment collection generates Unit, is corresponded respectively to, by least two, the segment collection set that the segment collection of different observation visual angle forms for generating；Single figure The segment that block is concentrated, obtains in dimensionally object model projects to image coordinate system according to same observation visual angle；Described seat Mark determines unit, for the coordinate according to the selected reference point in world coordinate system, determines that each segment concentrates each segment to exist Coordinate in described world coordinate system, splices the coordinate of electronic chart time institute foundation as the segment utilizing described segment to concentrate.

At least one technical scheme above-mentioned that the embodiment of the present application uses can reach following beneficial effect:

Owing to, in the segment collection set that server generates, corresponding respectively to the segment of different viewing angle including at least two Collection, therefore, when comprising the desired viewing angle of user in the electronic chart idsplay order received, can obtain and the described phase The segment that segment corresponding to viewing angle hoped is concentrated splices, to show electronic chart.Thus compared to prior art only For showing the electronic chart of the observation visual angle fixing corresponding to certain, the scheme flexibility that the embodiment of the present application provides is relatively High, it is possible to meet the actual demand of different user.

Accompanying drawing explanation

Accompanying drawing described herein is used for providing further understanding of the present application, constitutes the part of the application, this Shen Schematic description and description please is used for explaining the application, is not intended that the improper restriction to the application.In the accompanying drawings:

Fig. 1 is the geometrical relationship schematic diagram of the camera imaging in the embodiment of the present application；

Fig. 2 is the geometrical relationship schematic diagram of the image coordinate system in the embodiment of the present application and camera coordinates system；

The electronic map generating method that Fig. 3 provides for the embodiment of the present application realize schematic flow sheet；

Fig. 4 is the perspective view in the embodiment of the present application；

Fig. 5 is orthogonal projection schematic diagram in the embodiment of the present application；

Fig. 6 is the perspective view that there is the anglec of rotation in the embodiment of the present application；

The display method for electronic map that Fig. 7 provides for the embodiment of the present application realize schematic flow sheet.

Detailed description of the invention

For making the purpose of the application, technical scheme and advantage clearer, below in conjunction with the application specific embodiment and Technical scheme is clearly and completely described by corresponding accompanying drawing.Obviously, described embodiment is only the application one Section Example rather than whole embodiments.Based on the embodiment in the application, those of ordinary skill in the art are not doing Go out the every other embodiment obtained under creative work premise, broadly fall into the scope of the application protection.

Observation visual angle for solving client shows in prior art electronic chart corresponding is more single, and motility is poor Problem, the embodiment of the present application provide a kind of electronic chart display packing.

For ease of reader understanding, before the display packing of this electronic chart is introduced, first some technology are carried out letter Single introduction.Those technology include: one, electronic chart is from the implementation being generated to display；Two is relevant with generating electronic chart Three coordinate systems；Three, client and server cooperation displays for a user the implementation of electronic chart.Individually below to these skills Art is introduced one by one.

One, electronic chart is from the implementation being generated to display

Usually, electronic chart is from being generated to display it is generally required to through following step:

(1) first with road, river etc. as natural boundary, the geographic area of electronic chart to be generated is divided into several Block；

(2) by the shooting mode such as photo to building, the material object such as road, river, massif carries out material collection；

(3) digital adventure appearance to certain proportion chi extracts, the operation such as reduces the staff and be fabricated to fundamental geological base map；

(4) according to the material collected during material collection, in conjunction with certain satellite image map to building, massif etc. Dimensionally object model (abbreviation model) set up on geographical base map by atural object.Additionally, for ensureing that each model is on geographical base map The position gone up at the earth's surface of the position material object corresponding with this model the most consistent, model AnchorPoint can be arranged under it Centre of surface point position, consequently facilitating determine model position on geographical base map；

(5) according to the model obtained in step (4), in conjunction with certain projection theory, model is projected, obtain a certain The design sketch of fixed viewpoint, such as, obtain design sketch from above-mentioned model being carried out downward projection towards northeastwardly angle, obtaining Not modeling can also be added in step in (4) after design sketch on design sketch but in esse material object, as road, bridge, Water system, greenbelt etc.；

(6) design sketch is divided into segment；

(7) segment being divided into is published to electronic chart download platform so that such as client etc. it is achieved that from Segment downloaded by this platform, and utilizes the segment of download be spliced into electronic chart and show.

During above-mentioned map generalization electronically and display, prior art, by performing step (5), generally only generates Corresponding to the projection of certain fixing observation visual angle, therefore in step (7), as a example by client, client is spliced into also The electronic chart of display, also simply corresponds to the electronic chart at this Orientation observation visual angle.

In addition it should be noted that in above-mentioned steps (5), dimensionally object model is projected, camera can be related to Coordinate system and image coordinate system, and when utilizing segment be spliced into electronic chart and show, world coordinate system can be related to the most again. Hereinafter these three coordinate system is simply introduced.

Two three coordinate systems relevant with generating electronic chart

Mentioned here with generate relevant three coordinate systems of electronic chart, including camera coordinates system, image coordinate system and World coordinate system.Hereinafter the most simply introduce.

As it is shown in figure 1, be the geometrical relationship figure of camera (video camera in other words) imaging.Wherein, O point is video camera photocentre (projection centre), Xc axle is parallel with the x-axis of imaging plane coordinate system and y-axis with Yc axle, and Zc axle is camera optical axis, and image is put down Face xO1y is vertical, the focal length of a length of video camera of line segment between some O and some O1.Wherein, put O position, be equivalent to camera Point position, (or video camera) optical center.The principal point O1 that intersection point is image of junction point optical axis and the plane of delineation, by an O with The rectangular coordinate system of Xc, Yc and Zc axle composition, the referred to as coordinate system of video camera, i.e. camera coordinates system.

World coordinate system, is in order to describe the position of camera (or video camera) and to be introduced into, such as coordinate system in Fig. 1 OwXwYwZw is world coordinate system.Translation vector t and spin matrix R can be used to represent camera coordinates system and world coordinate system Relation.So, it is assumed that some homogeneous coordinates under world coordinate system in space are (Xw, Yw, Zw, 1)^T(T is to represent to turn here The symbol put), the homogeneous coordinates under camera coordinates are (Xc, Yc, Zc, 1)^T, then there is following relation:

$\left[\begin{array}{c}Xc\\ Yc\\ Zc\end{array}\right]=\left[\begin{array}{cc}R& t\\ \stackrel{\→}{0}& 1\end{array}\right]\left[\begin{array}{c}Xw\\ Yw\\ Zw\\ 1\end{array}\right]=M_1\left[\begin{array}{c}Xw\\ Yw\\ Zw\\ 1\end{array}\right]$

In above formula, R is the orthogonal matrices (also becoming spin matrix) of 3 × 3, and t is three-dimensional translation vector.Vector 0 =(0,0,0), M1 is 4 × 4 matrixes.

Refer to Fig. 2, for the geometrical relationship figure of image coordinate system and camera coordinates system.In Fig. 2, the plane of delineation (Image Plane) plane coordinate system at place is exactly image coordinate system；And projection centre o and coordinate axes i, j, k form camera coordinates System.Wherein, coordinate axes k, for camera (video camera) optical axis.F in figure, for the focal length of camera (video camera).

In the embodiment of the present application, camera view described hereinafter, it is in the plane in camera coordinates system.Hereinafter retouch That states projects, to dimensionally object model, the segment obtained, the plane being in image coordinate system.Dimensionally object model institute Corresponding atural object, then be in the actual object in world coordinate system.

Three, client and server cooperation

In the embodiment of the present application, client, it is mainly used in being responsible for downloading electronic chart from server and (specifically downloads For splicing the segment of electronic chart), and splice segment to show electronic chart；Server, then be mainly used in generating electronically Figure.

Hereinafter first introducing, in the embodiment of the present application, how server generates electronic chart.Then introduce client then, How to perform the display packing of the electronic chart that the embodiment of the present application provides, to realize display electronic chart.

As it is shown on figure 3, for the embodiment of the present application provide one map generalization method electronically, with realize user for When the observation visual angle that electronic chart is corresponding has different demands so that client disclosure satisfy that the demand of different user.The most right The method shown in Fig. 3 describes in detail.

Step S11: server generates and corresponded respectively to, by least two, the segment that the segment collection of different observation visual angle forms Collection set；

The segment that single segment is concentrated, is will be during dimensionally object model projects to image coordinate system according to same observation visual angle Obtain.

Atural object described in the embodiment of the present application, generally includes the various material objects having shape on ground, such as building, road Road, mountains and rivers, vegetation, river etc..The dimensionally object model mentioned in this embodiment, can be the shape chi of the atural object according to earth's surface The three-dimensional digital model (abbreviation model) of very little foundation, the threedimensional model set up such as the geomery according to building or massif etc.； According to the building in a city, the city threedimensional model etc. that massif etc. is set up.

Above-mentioned dimensionally object model is set up and is generally based on certain coordinate system and sets up, such as web Mercator projection Coordinate system, or the world coordinate system OXYZ etc. shown in Fig. 4.This embodiment is set up with dimensionally object model Example illustrates.Based on this world coordinate system, by camera view (as shown in Figure 4 with the several point of A, B, C, D as summit Rectangle plane, it is possible to be referred to as face ABCD) the dimensionally object model part observed projects in image coordinate system, available corresponding A segment.Wherein, image coordinate system is the most not shown.It will be understood by those skilled in the art that in image coordinate system Segment, is perpendicular with the camera optical axis by a camera view center image.

In the embodiment of the present application, the angle existed can be referred to as the angle of pitch, face ABCD phase between face ABCD and XOY plane The angle of rotation counterclockwise for Z axis is referred to as the anglec of rotation.Positive direction during additionally X-axis is typically described world coordinate system is just being pointed to East to coordinate axes, Y-axis is the coordinate axes that positive direction in described world coordinate system points to direct north.

By above it is known that this step is mentioned segment collection set, it it is the set being made up of segment collection.Single segment is concentrated Segment, obtains in dimensionally object model projects to image coordinate system according to same observation visual angle.One segment concentrates bag The segment contained, the anglec of rotation of its correspondence or be that the angle of pitch angularly determines that, all segments that segment is concentrated are spelled Connect the electronic chart that can show that a visual angle afterwards.For the generating mode of segment, described segment, can be such as Fig. 4 During shown camera view (i.e. face ABCD) translates relative to image coordinate system, with by camera view It is projecting direction that the camera optical axis of the heart points to the direction of dimensionally object model, according to the observation visual angle set, uses parallel throwing The mode of shadow will obtain during dimensionally object model projects to image coordinate system.Usually, described camera view, sit with camera The relation of the camera optical axis in mark system is: vertical relation.

Below with reference to projection theory when obtaining segment, the generation method of the segment that segment is concentrated is illustrated.As Shown in Fig. 2, face ABCD is camera view, and dimensionally object model is positioned on geographical base map, and geographical base map overlaps with face XOY, for Avoid situation elements " near big and far smaller " problem that central projection mode causes, it is ensured that in camera view, dimensionally object model is thrown Shadow ratio is consistent, and the embodiment of the present application specifies during projection obtains segment, and arranging video camera projection pattern is parallel projection, So, according to such projection pattern, all elements in camera view is projected to image coordinate system in parallel projection mode In.

Carry out projection when obtaining segment:

First, according to the boundary point in the geographical base map residing for dimensionally object model, as LT in Fig. 4 (x, y), RB (x, y) 2 points, determine drop shadow spread in XOY plane, and the enclosed scope of dotted line in the XOY plane shown in Fig. 4 represents drop shadow spread, Represent the geographic range that geographical base map is corresponding simultaneously；

Then, camera view width W and length H are set, and the image resolution ratio of desired segment is set.This In application embodiment, the value of W and H can be equal, and the image resolution ratio of each segment can be predefined for 256 × 256.Due to video camera The width W of view and length H, for the length in world coordinate system, therefore by size and the figure of segment of camera view As resolution, X-direction that each pixel of available segment represents in world coordinate system respectively and the actual geographic of Y-direction away from From δ x, δ y.Wherein, δ x=W/256, δ x=H/256.Such as segment in one image coordinate system, right in world coordinate system Should in the geographic area of 50 meters × 50 meters, and, the image resolution ratio of this segment is 256 × 256, then, this segment comprises The actual geographic distance δ x of the X-direction that single pixel represents in world coordinate system can be obtained divided by 256 by 50, and i.e. 0.195 Rice, similarly, the actual geographic distance δ y of the Y-direction that the single pixel that this segment comprises represents in world coordinate system can be by 50 obtain divided by 256, i.e. 0.195 meter.Finally, control the change in location of camera view and realize simulation and take photo by plane process, thus To each segment.The process that simulation mentioned here is taken photo by plane, specifically refers to, and keeps camera view and the ginseng in world coordinate system Examine the angle between benchmark constant (as kept the angle between camera view and XOY plane constant), and keep video camera to regard Figure is constant at a distance of the distance (namely height of camera view) of XOY plane, takes the photograph by rule from left to right, from top to bottom is mobile Camera view.That is, it is positioned at above a LT with camera view, as the initial position residing for camera view, according to described rule Then mobile camera view, until camera view moves to being positioned at above a RB.By such move mode, it is ensured that Dimensionally object model in described drop shadow spread, is all projected face A ' B ' C ' D ' and covered.Camera view often moves once, position Dimensionally object model in camera view view field can be projected to image coordinate system once, thus obtains a figure Block.In such a manner, each segment corresponding to whole described drop shadow spread, and then all figures that will obtain are finally given Block is saved in a segment and concentrates.After changing the angle between the basis reference in camera view and world coordinate system, according to Above-mentioned simulation is taken photo by plane process, can continue to obtain another segment collection including a large amount of segment.

It should be noted that the angle between basis reference in described camera view and world coordinate system, it is this Observation visual angle described in application embodiment.When XOY plane during described basis reference is Fig. 4, camera view and XOY Between angle be observation visual angle, can be described as the angle of pitch；When Z axis during described basis reference is Fig. 4, camera view phase The anglec of rotation for Z axis is observation visual angle, can be described as the anglec of rotation.

In the embodiment of the present application, described at least two corresponds respectively to the segment collection of different observation visual angle, may include that

Correspond respectively to the segment collection of the different angles of pitch；Or

Correspond respectively to the segment collection of the different anglecs of rotation；Or

At least one is corresponding to the segment collection of certain angle of pitch, and, at least one is corresponding to the segment collection of certain anglec of rotation；

Etc..

Step S12: server, according to the coordinate of the selected reference point in world coordinate system, determines that each segment is concentrated each Segment coordinate in described world coordinate system, splices electronic chart time institute foundation as the segment utilizing described segment to concentrate Coordinate.

The coordinate of segment, in the embodiment of the present application, that pixel generally referring to be positioned at the segment upper left corner (claims P afterwards Point) coordinate in world coordinate system.At the coordinate P of world coordinate system, (x is y) to splice segment to make the pass of electronic chart to P point Key and premise, guarantee correctness and the accuracy of P point as far as possible, could ensure the nothing between segment when Subsequent electronic map denotation Seam splicing.Individually below for the segment of the different angles classification that may relate in the embodiment of the present application, introduce respectively one Individual segment is concentrated, and how to determine each segment that this segment concentrates coordinate in world coordinate system.This coordinate, namely segment P point coordinate in world coordinate system.

1) when segment is orthogonal projection figure

Segment is that the generation process of orthogonal projection figure, i.e. segment is:

As it is shown in figure 5, in the case of camera view is paralleled with the XOY plane in world coordinate system, with by taking the photograph It is projecting direction that the camera optical axis at camera view center points to the direction of dimensionally object model, regards by moving in parallel video camera Figure, uses the mode of parallel projection will obtain each segment during dimensionally object model projects to image coordinate system.Wherein, take the photograph described in Camera view is vertical with described camera optical axis.

If assuming the coordinate on four summits of the perspective plane A ' B ' C ' D ' shown in Fig. 5, for certain rectangle in image coordinate system The coordinate of the world coordinate system of four vertex correspondence of segment, then, angle point alive boundary, A ' B ' C ' D ' upper left, perspective plane coordinate system Middle coordinate A ' (x, y), it is simply that it is desirable that the coordinate that the P point calculated is in world coordinate system.Because face ABCD is parallel to face XOY, Then (x, y) with perspective plane A ' B ' C ' D ' central point for the coordinate centerV in world coordinate system of the face ABCD central point shown in Fig. 5 Coordinate centerP in world coordinate system (x, y) meets:

CenterV (x, y)=centerP (x, y) (1)

Belong to parallel projection because of face ABCD to face A ' B ' C ' D ' again, then A ' (x, y) coordinate meet:

$\left\{\begin{array}{c}{A}^{\′}.x=centerP.x-W*0.5\\ A^{\′}.y=centerP.y+H*0.5\end{array}\right.---\left(2\right)$

Wherein, A ' .x is that (x, y) coordinate of the X-axis in coordinate, A ' .y is A ' (x, y) coordinate of the Y-axis in coordinate to A '；W For the width of camera view, H is the length of camera view, and in this embodiment, W and H is equal, and, in this embodiment, W and H is the width that represents in world coordinate system of single segment and length.Understand in conjunction with formula (1) and formula (2), camera view (x, (x, y) in the world y) to determine segment upper left corner A ' for the initial position of central point coordinate centerV in world coordinate system Coordinate in coordinate system.Wherein, the initial position of camera view central point, it is assumed that the some LT that is positioned in world coordinate system (x, Y) surface.

In the embodiment of the present application, calculate A ' (x, during coordinate y) put, first according to as in Fig. 4 LT (x, y),The length and width of the rectangle frame in the world coordinate system that 2 points (not shown in Fig. 5) determine, in conjunction with single segment The width W represented in world coordinate system and length H, calculate the segment square that a segment concentrates all segments comprised to be constituted Columns n c of battle array and line number nr.

Define arrays arrc [nc], arrr [nr], 0≤i≤nc, 0≤j≤nr, and wherein, i represents that segment is at figure block matrix In the numbering of residing row, j represents the numbering of the row residing in figure block matrix of segment.So, the figure in the figure block matrix upper left corner Block is defined as arrc [0], arrr [0], and in figure block matrix, the segment of the i-th row jth row is at figure to make arrc [i], arrr [j] then represent Location in block matrix.For avoiding adjacent segment to there is crack after splicing from visual effect between segment, because of This embodiment of the present application takes and ensures that mode upper and lower, that left and right all overlaps region is i.e., it is possible to arrange shooting Machine view is camera view length or wide 90% at the take photo by plane single amount of movement of process of simulation.Above-mentioned camera view central point Coordinate LT in world coordinate system (x, y) on the basis of the coordinate of point, datum mark coordinate calculate the video camera after other translations View center position, during camera view translation, any camera view central point meets:

$\left\{\begin{array}{c}centerV.x=LT.x+arrc\[i\]*W*0.9\\ centerV.y=LT.y-arrr\[j\]*H*0.9\end{array}\right.---\left(3\right)$

Can be in the case of the orthogonal projection without angle of pitch irrotationality corner by formula (1)～(3), any segment upper left corner point P_n(x, y) the coordinate computing formula in world coordinate system is:

$\left\{\begin{array}{c}{P}_n.x=LT.x+arrc\[i\]*W*0.9-W*0.5\\ P_n.y=LT.y-arrc\[j\]*H*0.9+H*0.5\end{array}\right.---\left(4\right)$

N in formula, is used for representing that projection pattern is: without the orthogonal projection of angle of pitch irrotationality corner.

2) when segment is the projection that there is the angle of pitch

Orthogonal projection design sketch without the angle of pitch is obvious not with 2 d plane picture difference on effect, and increasing the angle of pitch can show Go out the elevation information of dimensionally object model, and the hiding relation between model, strengthen the spatial entities performance energy of electronic chart Power.

Understand in conjunction with Fig. 4 and Fig. 5, the camera view ABCD shown in Fig. 5 is rotated around X and can produce the angle of pitch, angle For α.Due to the existence of the angle of pitch, camera view projects to image during simulation is taken photo by plane and sits described dimensionally object model Mark system thus after obtaining segment, segment project in the XOY plane of world coordinate system the projection plane obtained in the Y-axis direction by Stretching, illustrates the actual geographic distance H ' that the segment that the camera view projection of a length of H obtains represents in world coordinate system Meet:

H '=H/cos α (5)

With the coordinate LT of camera view central point initial position in world coordinate system (x, y) on the basis of point, it is known that take the photograph (x, y) to XOY plane distance H for camera view central point LT_c, then have:

$tan\mathrm{\α}=\frac{LT.y-H^{\′}*0.5-centerV.y}{Hc}---\left(6\right)$

Datum mark LT (x, y) the Y-axis coordinate in world coordinate system can be drawn according to formula (5) and formula (6) CenterV.y is:

$centerV.y=LT.y-tan\mathrm{\α}*Hc-\frac{H}{2cos\mathrm{\α}}---\left(7\right)$

Can be obtained by formula (1), (2), (4), (7), there is the angle of pitch and in the case of irrotationality corner, take photo by plane process via simulation Any segment upper left corner point obtained coordinate P in world coordinate system_h(x, computing formula y) is:

$\left\{\begin{array}{c}{P}_h.x=LT.x+arrc\[i\]*W*0.9-W*0.5\\ P_h.y=LT.y-tan\mathrm{\α}*Hc-\frac{H}{2\cos \mathrm{\α}}-arrc\[j\]*H*0.9+H*0.5\end{array}\right.---\left(8\right)$

From formula (8), there is angle of pitch α and in the case of irrotationality corner, segment X-axis under world coordinate system is sat Mark P_h.x computing formula, the X-axis coordinate P under world coordinate system when being orthogonal projection figure with segment_h.x computing formula phase With.Wherein, (x y) is the initial position (datum mark) of the camera view central point coordinate in world coordinate system to LT.It addition, H in formula, for represent the simulation that this formula is corresponding take photo by plane during projection pattern be: have the throwing of angle of pitch irrotationality corner Shadow.

3) when segment is the projection that there is the angle of pitch and the anglec of rotation

As shown in Figure 6, Y-axis positive direction points to direct north, and X-axis positive direction points to direction, due east, horizontally rotates video camera Before view, camera view i.e. eye-observation direction is towards Y-axis positive direction, and face ABCD is that camera view is thrown in XOY face Shadow.After horizontal rotation β angle, eye-observation direction is towards Y ' direction.For ensureing that electronic cartography completes after-vision angle Identical with now viewing angle, OY ' is pointed to the direct north being set to suppose meaning, sets up local coordinate system, initial point is constant, with OX ' direction is X-direction, with OY ' direction as Y direction.With Z axis (0,0,1) for rotary shaft, β is that the anglec of rotation creates coordinate system Transition matrix T:

$T=\left(\begin{array}{ccc}cos\mathrm{\β}& sin\mathrm{\β}& 0\\ -sin\mathrm{\β}& \cos \mathrm{\β}& 0\\ 0& 0& 1\end{array}\right)---\left(9\right)$

Then Subgraph block upper left angle point P after horizontal rotation_r(x, y) coordinate meets:

P_r(x, y, 0)=P_h(x,y,0)T (10)

After coordinate system transformation, in the case of the angle of pitch exists with horizontal rotation, according to formula (9) and formula simultaneously (10), any segment upper left corner point P_r(x, y) the coordinate computing formula in world coordinate system is:

$\left\{\begin{array}{c}{P}_r.x=P_n.xcos\mathrm{\β}+P_h.ysin\mathrm{\β}\\ P_r.y=-P_n.xsin\mathrm{\β}+P_h.ycos\mathrm{\β}\end{array}\right.---\left(11\right)$

R in formula, is used for representing that projection pattern is: has the angle of pitch and has the projection of the anglec of rotation.

Above-mentioned describe orthogonal projection respectively, there is the angle of pitch and there is the angle of pitch and the anglec of rotation simultaneously in the case of During to segment, the determination method of the top left co-ordinate point of segment.After determining each segment coordinate in world coordinate system, When being subsequently generated electronic chart, can (x, y), and each pixel of segment be in X-direction and Y side according to the coordinate P of segment To actual geographic distance δ represented respectively_x、δ_yDetermine the position relationship between segment, specifically determine that process is as follows:

First the order that can define in figure block matrix the segment corresponding to the position in the upper left corner is arrc [0], arrr [0], the datum mark spliced as other segment using this segment coordinate in world coordinate system, P_(i,j)(x y) represents arrc [i], arrr [j] segment coordinate in world coordinate system, then arrc [i], arrr [j] segment and datum mark segment it Between in image coordinate system the number of pixels along X-direction and the number of pixels along Y direction can distinguish the most true Fixed:

Wherein, δ_x、δ_yThe actual geographic distance represented respectively in world coordinate system for each pixel of segment, by above-mentioned Formula, according to the number of pixels at interval between each segment and the segment of datum mark, and the number of pixels that single segment comprises, I.e. can determine that each segment position at image coordinate system, it is achieved the splicing between segment.

By above-mentioned steps S12 so that each segment that the segment that server obtains is concentrated, all to there being world coordinate system In coordinate.Afterwards, server can issue segment collection and segment concentrates each segment comprised seat in world coordinate system Mark, in order to client can download segment collection and segment concentrates each segment comprised coordinate in world coordinate system.

Use the embodiment of the present application provide electronic map generating method, due to server generate segment collection set in, The segment collection of different viewing angle is corresponded respectively to, therefore, when the electronic chart that subsequent client receives including at least two When comprising the desired viewing angle of user in idsplay order, client can obtain that server provides and described desired sight The segment examining segment concentration corresponding to angle splices, to show electronic chart.Thus be only able to display compared to prior art For electronic chart corresponding to certain fixing observation visual angle, the scheme flexibility that the embodiment of the present application provides is higher, it is possible to Meet the actual demand of different user.

Above-described embodiment describes map generalization method electronically in detail, corresponding with map generalization method electronically, this Application also provides for the display packing embodiment of a kind of electronic chart, as it is shown in fig. 7, the method embodiment includes following step Rapid:

Step S21: client receives electronic chart idsplay order, in described electronic chart idsplay order, including for three The information of the observation visual angle of dimension ground object model；

Observation visual angle mentioned here, can be such as the angle of pitch and/or the anglec of rotation.

Additionally, in described electronic chart idsplay order in addition to including the information of described observation visual angle, it is also possible to include it The camera view when initial position of the camera view central point that premise arrives coordinate in world coordinate system, projection is to generation The information such as the distance of the XOY plane in boundary's coordinate system and the size of camera view.

The information such as above-mentioned electronic chart idsplay order is typically triggered by user, observation visual angle can also be in client Show in advance, select for user.Such as, user can click on selection display on the electronic chart of client interface to be shown The angle of pitch is the electronic chart etc. of 45 °.

Step S22: client is according to the information of described observation visual angle, and it is right to obtain from the segment collection set that server generates The segment collection of observation visual angle described in Ying Yu.

Wherein, described segment collection set includes that at least two corresponds respectively to the segment collection of different observation visual angle；Single figure The segment that block is concentrated, obtains in dimensionally object model projects to image coordinate system according to same observation visual angle.

In this step, according to the observation visual angle (such as the angle of pitch or the anglec of rotation) comprised in electronic chart idsplay order, i.e. Can determine that the segment collection matched with described observation visual angle.When determining the segment collection matched with described observation visual angle, such as, see Examining visual angle is the angle of pitch 60 °, then obtain the segment collection corresponding to the angle of pitch 60 ° in the set of segment collection.

Client can be after receiving described electronic chart idsplay order, by the sight in described electronic chart idsplay order The information examining visual angle is sent to server, the segment matched with described observation visual angle preserved with inquiry download server Collection；Or, client can download the segment collection corresponding to different observation visual angles from server in advance, and downloads different segment Collection and the mapping relations of observation visual angle, then, client, after receiving described electronic chart idsplay order, can be protected in this locality The segment corresponding to different observation visual angles deposited is concentrated, and inquires about and obtains and the observation visual angle in described electronic chart idsplay order The corresponding segment collection of information.

Step S23: the segment that client is concentrated according to the segment that gets coordinate in world coordinate system, splices and adds Carry the segment of the segment concentration got to show electronic chart.

The segment mentioned here coordinate in world coordinate system, also downloads from server and obtains.Usually, client Hold when downloading segment collection, also can download the segment coordinate in world coordinate system that segment is concentrated.

In step S23, the segment that client is concentrated according to segment coordinate in world coordinate system, can be in conjunction with segment Concentrate segment and the coordinate information of segment, splice and load described segment to show electronic chart.Wherein, before joining method By the agency of mistake, i.e. according to the number of pixels at interval between each segment and the segment of datum mark, and the picture that single segment comprises Element number, determines each segment position in image coordinate system；After determining position, can according to image mosaic mode, Realize segment splicing.Splicing result, is the image as electronic chart.This image is shown by client, i.e. achieves Display to electronic chart.

The method provided by this embodiment, user show electronic chart time, idsplay order can include for The dimensionally information of the observation visual angle of object model, user often selects a view angle switch, can generate according to above three step The electronic chart corresponding with the visual angle after switching, so that client can show corresponding to different observation visual angles electronically Figure, the observation visual angle solving electronic chart that client in prior art shows corresponding is more single, poor the asking of motility Topic.

It addition, in the electronic chart idsplay order that receives of the client of above-mentioned steps S21, it is also possible to include the described world The positional information of the viewing area in coordinate system.Then, in above-mentioned steps S23, the figure that client is concentrated according to the segment got Block coordinate in world coordinate system, splices and loads the segment that the segment got is concentrated, specifically may include that

Client according to the positional information of described viewing area, and described in the segment concentrated of the segment that gets in the world Coordinate in coordinate system, from the segment that the described segment collection got comprises, the coordinate being chosen in world coordinate system falls into The segment of described viewing area；Client, according to the segment chosen coordinate in world coordinate system, is spliced and is loaded and select Segment.

The pixel pair of four corners of the display screen such as comprising client in the display request that client receives Coordinate figure under the world coordinate system answered, each segment concentrated due to segment all has the coordinate in world coordinate system, according to The segment that above-mentioned coordinate figure comprises in the range of i.e. can determine that coordinate figure, the most then the figure that splicing comprises in loading above-mentioned coordinate range Block.On the display screen of client, so then it is presented as the electronic chart in the range of preferential display screen, screen is shown Electronic chart outside scope then follow-up can reload display or not carry out loaded and displayed.

Corresponding with said method embodiment, the embodiment of the present application also provides for the display device of a kind of electronic chart, described aobvious Showing device is applied in client, and described display device includes: reception unit, segment acquiring unit and splicing loading unit, wherein,

Described reception unit, is used for receiving electronic chart idsplay order；In described electronic chart idsplay order, including for The dimensionally information of the observation visual angle of object model；

Described segment acquiring unit, for the information according to described observation visual angle, the segment collection set generated from server Middle acquisition is corresponding to the segment collection of described observation visual angle；Wherein, described segment collection set includes that at least two corresponds respectively to not Segment collection with observation visual angle；The segment that single segment is concentrated, is will dimensionally to project to by object model according to same observation visual angle Image coordinate system obtains；

Described splicing loading unit, is used for the coordinate in world coordinate system of the segment according to the segment concentration got, Splice and load the segment of the segment concentration got to show electronic chart.

Corresponding with said method embodiment, the embodiment of the present application also provides for the generating means of a kind of electronic chart, described life Becoming device to apply at server, described generating means includes: segment collection signal generating unit and coordinate determine unit, wherein,

Described segment collection signal generating unit, for generating the segment collection group being corresponded respectively to different observation visual angle by least two The segment collection set become；The segment that single segment is concentrated, is dimensionally will to project to image by object model according to same observation visual angle Coordinate system obtains；

Described coordinate determines unit, for the coordinate according to the selected reference point in world coordinate system, determines each figure Block concentrates each segment coordinate in described world coordinate system, during as the segment splicing electronic chart utilizing described segment to concentrate The coordinate of institute's foundation.

Those skilled in the art are it should be appreciated that embodiments herein can be provided as method, system or computer program Product.Therefore, the reality in terms of the application can use complete hardware embodiment, complete software implementation or combine software and hardware Execute the form of example.And, the application can use at one or more computers wherein including computer usable program code The upper computer program product implemented of usable storage medium (including but not limited to disk memory, CD-ROM, optical memory etc.) The form of product.

The application is with reference to method, equipment (system) and the flow process of computer program according to the embodiment of the present application Figure and/or block diagram describe.It should be understood that can the most first-class by computer program instructions flowchart and/or block diagram Flow process in journey and/or square frame and flow chart and/or block diagram and/or the combination of square frame.These computer programs can be provided Instruction arrives the processor of general purpose computer, special-purpose computer, Embedded Processor or other programmable data processing device to produce A raw machine so that the instruction performed by the processor of computer or other programmable data processing device is produced for real The device of the function specified in one flow process of flow chart or multiple flow process and/or one square frame of block diagram or multiple square frame now.

These computer program instructions may be alternatively stored in and computer or other programmable data processing device can be guided with spy Determine in the computer-readable memory that mode works so that the instruction being stored in this computer-readable memory produces and includes referring to Make the manufacture of device, this command device realize at one flow process of flow chart or multiple flow process and/or one square frame of block diagram or The function specified in multiple square frames.

These computer program instructions also can be loaded in computer or other programmable data processing device so that at meter Perform sequence of operations step on calculation machine or other programmable devices to produce computer implemented process, thus at computer or The instruction performed on other programmable devices provides for realizing at one flow process of flow chart or multiple flow process and/or block diagram one The step of the function specified in individual square frame or multiple square frame.

In a typical configuration, calculating equipment includes one or more processor (CPU), input/output interface, net Network interface and internal memory.

Internal memory potentially includes the volatile memory in computer-readable medium, random access memory (RAM) and/or The forms such as Nonvolatile memory, such as read only memory (ROM) or flash memory (flashRAM).Internal memory is showing of computer-readable medium Example.

Computer-readable medium includes that removable media permanent and non-permanent, removable and non-can be by any method Or technology realizes information storage.Information can be computer-readable instruction, data structure, the module of program or other data. The example of the storage medium of computer includes, but are not limited to phase transition internal memory (PRAM), static RAM (SRAM), moves State random access memory (DRAM), other kinds of random access memory (RAM), read only memory (ROM), electric erasable Programmable read only memory (EEPROM), fast flash memory bank or other memory techniques, read-only optical disc read only memory (CD-ROM), Digital versatile disc (DVD) or other optical storage, magnetic cassette tape, the storage of tape magnetic rigid disk or other magnetic storage apparatus Or any other non-transmission medium, can be used for the information that storage can be accessed by a computing device.According to defining herein, calculate Machine computer-readable recording medium does not include temporary computer readable media (transitorYmedia), such as data signal and the carrier wave of modulation.

Also, it should be noted term " includes ", " comprising " or its any other variant are intended to nonexcludability Comprise, so that include that the process of a series of key element, method, commodity or equipment not only include those key elements, but also wrap Include other key elements being not expressly set out, or also include want intrinsic for this process, method, commodity or equipment Element.In the case of there is no more restriction, statement " including ... " key element limited, it is not excluded that including key element Process, method, commodity or equipment there is also other identical element.

It will be understood by those skilled in the art that embodiments herein can be provided as method, system or computer program. Therefore, the embodiment in terms of the application can use complete hardware embodiment, complete software implementation or combine software and hardware Form.And, the application can use can be with depositing at one or more computers wherein including computer usable program code The shape of the upper computer program implemented of storage media (including but not limited to disk memory, CD-ROM, optical memory etc.) Formula.

These are only embodiments herein, be not limited to the application.To those skilled in the art, The application can have various modifications and variations.All made within spirit herein and principle any amendment, equivalent, Improve, within the scope of should be included in claims hereof.

Claims (10)

1. the display packing of an electronic chart, it is characterised in that including:

Client receives electronic chart idsplay order；In described electronic chart idsplay order, including for dimensionally object model The information of observation visual angle；

Client, according to the information of described observation visual angle, obtains corresponding to described observation from the segment collection set that server generates The segment collection at visual angle；Wherein, described segment collection set includes that at least two corresponds respectively to the segment collection of different observation visual angle；Single The segment that individual segment is concentrated, obtains in dimensionally object model projects to image coordinate system according to same observation visual angle；

The segment that client is concentrated according to the segment that gets coordinate in world coordinate system, splices and loads the figure got The segment that block is concentrated is to show electronic chart.

Method the most according to claim 1, it is characterised in that in described electronic chart idsplay order, also include described generation The positional information of the viewing area in boundary's coordinate system；

The segment that client is concentrated according to the segment that gets coordinate in world coordinate system, splices and loads the figure got The segment that block is concentrated, including:

Client according to the positional information of described viewing area, and described in the segment concentrated of the segment that gets at world coordinates Coordinate in system, from the segment that the described segment collection got comprises, the coordinate being chosen in world coordinate system falls into described The segment of viewing area；

Client, according to the segment chosen coordinate in world coordinate system, is spliced and loads the segment selected.

3. method as claimed in claim 2, it is characterised in that client is according to the segment chosen seat in world coordinate system Mark, splices and loads the segment selected, including:

Client is according to the segment selected coordinate in world coordinate system, the default splicing benchmark in described image coordinate system Point coordinate in world coordinate system, and in described image coordinate system, single pixel is corresponding in described world coordinate system Geographic distance, splices and loads the segment selected.

4. a map generalization method electronically, it is characterised in that including:

Server generates and is corresponded respectively to, by least two, the segment collection set that the segment collection of different observation visual angle forms；Single figure The segment that block is concentrated, obtains in dimensionally object model projects to image coordinate system according to same observation visual angle；

Server, according to the coordinate of the selected reference point in world coordinate system, determines that each segment concentrates each segment in described generation Coordinate in boundary's coordinate system, splices the coordinate of electronic chart time institute foundation as the segment utilizing described segment to concentrate.

Method the most according to claim 4, it is characterised in that described observation visual angle, including the angle of pitch and/or the anglec of rotation；

The described angle of pitch, for the folder between the given plane in the camera optical axis in camera coordinates system and described world coordinate system Angle；Described given plane, for the plane determined by the X-axis in described world coordinate system and Y-axis；Described X-axis, sits for the described world Positive direction in mark system points to the coordinate axes in direction, due east；Described Y-axis, points to positive north for the positive direction in described world coordinate system The coordinate axes in direction；

The described anglec of rotation, for described camera optical axis relative to the anglec of rotation of the Z axis in described world coordinate system；Described Z axis, For described world coordinate system is perpendicular to the coordinate axes of described given plane.

Method the most according to claim 5, it is characterised in that described segment, for camera view relative to image coordinate During system translates, with the direction of dimensionally object model described in described camera optical axis points to as projecting direction, according to The observation visual angle set, uses the mode of parallel projection to obtain described during dimensionally object model projects to image coordinate system；

Described camera view, in camera coordinates system, be perpendicular to the plane of described camera optical axis.

Method the most according to claim 6, it is characterised in that when described observation visual angle includes the angle of pitch, server according to The coordinate of the selected reference point in world coordinate system, determines that each segment concentrates each segment seat in described world coordinate system Mark, including:

Server performs respectively for arbitrary segment:

The central point according to described camera view initial position residing in described translation motion is at described world coordinate system In coordinate, projection time described camera view and described given plane distance, described in described world coordinate system Camera view size in described world coordinate system, the segment that the described angle of pitch is corresponding with described initial position with this segment Between interval segment number, calculate this segment coordinate in described world coordinate system.

Method the most according to claim 6, it is characterised in that when described observation visual angle includes the angle of pitch and the anglec of rotation, clothes Business device, according to the coordinate of the described selected reference point in world coordinate system, determines that each segment concentrates each segment in the described world Coordinate in coordinate system, including:

Server performs respectively for arbitrary segment:

The central point according to described camera view initial position residing in described translation motion is at described world coordinate system In coordinate, projection time described camera view and described given plane distance, described in described world coordinate system Camera view size, the described angle of pitch, the described anglec of rotation and this segment in described world coordinate system and described initial bit Put the segment number at interval between the segment of correspondence, calculate this segment coordinate in described world coordinate system.

9. the display device of an electronic chart, it is characterised in that described display device applications in client, described display device Including: reception unit, segment acquiring unit and splicing loading unit, wherein,

Described reception unit, is used for receiving electronic chart idsplay order；In described electronic chart idsplay order, including for three-dimensional The information of the observation visual angle of ground object model；

Described segment acquiring unit, for the information according to described observation visual angle, obtains from the segment collection set that server generates Take the segment collection corresponding to described observation visual angle；Wherein, described segment collection set includes that at least two corresponds respectively to different sight Examine the segment collection at visual angle；The segment that single segment is concentrated, is dimensionally will to project to image by object model according to same observation visual angle Coordinate system obtains；

Described splicing loading unit, is used for the coordinate in world coordinate system of the segment according to the segment concentration got, splicing And load the segment of the segment concentration got to show electronic chart.

10. the generating means of an electronic chart, it is characterised in that described generating means is applied at server, described generation fills Put and include: segment collection signal generating unit and coordinate determine unit, wherein,

Described segment collection signal generating unit, is corresponded respectively to what the segment collection of different observation visual angle formed for generating by least two Segment collection set；The segment that single segment is concentrated, is dimensionally will to project to image coordinate by object model according to same observation visual angle System obtains；

Described coordinate determines unit, for the coordinate according to the selected reference point in world coordinate system, determines each segment collection In each segment coordinate in described world coordinate system, as utilize described segment to concentrate segment splicing electronic chart time depended on According to coordinate.