CN103678587B - Progressive transmission of spatial data and device - Google Patents
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- 230000005540 biological transmission Effects 0.000 title claims abstract description 44
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Abstract
The invention discloses a kind of progressive transmission of spatial data and device, this method includes：Ask transmitting terminal to send incremental data request and arrive receiving terminal, the request of data includes active view magnification ratio；The receiving terminal is analyzed the active view magnification ratio to obtain incremental data and incremental data is sent back into the request transmitting terminal；And the request transmitting terminal receives the incremental data.Pass through above-mentioned technical proposal, the transmission in progress of the lossless display of spatial data can be realized, accomplish adaptive transmission in progress, and arbitrarily complicated vector data is during progressive transmission is carried out, the correct display of vector data spatial relationship and between vector data in itself can be remained, the spatial data of magnanimity is realized quick transmission and is shown, it is ensured that data lossless can be shown, volume of transmitted data is reduced simultaneously, the efficiency of transmission of data is improved.
Description
Technical field
The present invention relates to spatial data transmission method and transmission device, in particular it relates to a kind of progressive transmission of spatial data
And device.
Background technology
Spatial entities be to exist or virtual entity or phenomenon in natural world it is abstract, with locus or feature
It is associated, is not subdivisible minimum unit in natural world, basic spatial entities has point, line, surface and the type of body four.
Spatial data be used for locus, shape information and the spatial relationship of representation space entity in itself, such as topological relation information, its
Spatial data structure is divided into vector data structure and raster data structure, and vector data structure is described with spatial spreading point coordinates
Spatial entities, the whole space of research is considered as a spatial domain by it, and spatial entities are as independent object distribution in the spatial domain；
Space is divided into uniform grid by raster data structure, real for describing the space with continuously distributed feature in certain space
Body.
With the fast development of Spatial Information Technology, obtain high-resolution, high-precision spatial data and be possibly realized, be based on
Hair of the extensive use of the spatial information of network to GIS (Geographic Information System, GIS-Geographic Information System)
Exhibition and application bring opportunity, also bring challenge.For the increase of the relatively existing network bandwidth, the number of Space-based information transmission
It is in explosive growth according to amount.In order to transmit and reduce network delay on demand, the massive spatial data of fine map is solved
Real-time adaptive quickly transmission and display problem one of important channel be spatial data progressive transmission.Spatial data is divided into
Raster data and the big Data Structures of vector data two.The piecemeal progressive transmission of raster data has had more perfect solution party
Case, and the spatial relationship between object vector is complicated, is also not suitable for using method of partition, therefore, the research of current progressive transmission is entered
Exhibition is unsatisfactory, there is following problem：
1st, need to pre-process initial data, by multiple dimensioned Bedding storage, if initial data changes, need
Again to handle, that is, add memory space, the transmission in progress of lossless display can not be realized again, i.e., can not accomplish adaptive progressive
Transmission.Substantial amounts of control information is added when the 2nd, transmitting so that vector data is from progressive transmission is started, until initial data is weighed
Build, the data volume transmitted altogether greatly exceed original data volume.It wherein cannot ensure that arbitrarily complicated vector data is carried out
During progressive transmission, the correct display of vector data spatial relationship and between vector data in itself is remained, is restriction arrow
Measure the practical critical problem of data progressive transmission.
The content of the invention
The purpose of the present invention overcomes the problem of control information data volume is excessive, and there is provided a kind of sky that can quickly transmit
Between data progressive transmission method and device.
To achieve these goals, the invention provides a kind of progressive transmission of spatial data, this method includes：Request
Transmitting terminal sends incremental data request and arrives receiving terminal, and the request of data includes active view magnification ratio；The receiving terminal
The active view magnification ratio is analyzed to obtain incremental data and the incremental data is sent back into the request transmitting terminal；
And the request transmitting terminal receives the incremental data.
Preferably, the step of receiving terminal analysis obtains incremental data includes：The receiving terminal is put by the view
Vast scale carries out abbreviation to the spatial data；And the luv space data of increment condition are determined for compliance with for the incremental number
According to.
Preferably, the receiving terminal carries out the process bag of abbreviation by the view magnification ratio to the spatial data
Include：Using the first abbreviation threshold value reciprocal as vector data of the map magnification ratio of active view；Pass through first abbreviation
Threshold value, carries out abbreviation to the spatial data, regard the data after abbreviation as current abbreviation result；With the space number formerly cached
According to magnification ratio the second abbreviation threshold value as vector data reciprocal；And by the second abbreviation threshold value, to described
Spatial data carries out abbreviation, regard the data after abbreviation as first abbreviation result.
Preferably, the corresponding luv space data of view coordinate for being determined for compliance with increment condition are the mistake of the incremental data
Journey includes：By the position in the luv space data after abbreviation in luv space data and the spatial data formerly cached
Position identical original coordinates point of the middle coordinate points in luv space data is removed；And determine that the spatial data retained is institute
State incremental data.
Preferably, the request transmitting terminal, which receives the incremental data step, also includes：The request Sender side Storage has
Also include the corresponding following view parameter of request incremental data in the spatial data formerly cached, the request of data：Space number
The coordinate points of the magnification ratio of the spatial data according to identification number, formerly cached and the spatial data formerly cached are in luv space
Positional information in data；And the incremental data is inserted into the spatial data formerly cached.
Preferably, the step that the incremental data of the reception is inserted into the spatial data formerly cached includes：Obtain
Take the positional information of the original coordinates point in the incremental data；And according to the positional information by the incremental data
Original coordinates point is inserted into the correspondence position in the spatial data formerly cached.
Preferably, the process incremental data of the reception being inserted into the spatial data formerly cached includes：
Using the magnification ratio of the spatial data formerly cached as the view window magnification ratio in the view control parameter, according to
The original coordinates point of the incremental data and the spatial data formerly cached is converted respectively according to the magnification ratio and obtained
The view coordinate points of the view window；Search corresponding with the view coordinate points that the incremental data original coordinates point transformation is obtained
View window on the view coordinate points of the original coordinates point transformation of spatial data that formerly cache described in pixel identical；By institute
The original coordinates point for stating incremental data is inserted into view window pixel and its phase corresponding to the view coordinate points after the conversion
Behind the original coordinates point of the same spatial data formerly cached；And replace the spatial data formerly cached
Magnification ratio is the active view window magnification ratio in the view control parameter.
To achieve these goals, the invention provides a kind of spatial data progressive transmission device, described device includes please
Dispensing device and reception device are asked, wherein：The send-request unit is configured to send incremental data request to the reception dress
Put, wherein, the request of data includes active view magnification ratio；The reception device is configured to put the active view
Vast scale is analyzed to obtain incremental data and the incremental data is sent back into the send-request unit；And the request hair
Device is sent to be configured to receive the incremental data.
Preferably, the reception device is configured to carry out abbreviation to the spatial data by the view magnification ratio；
And the luv space data of increment condition are determined for compliance with for the incremental data.
Preferably, the reception device is configured to：Vector data is used as using the inverse of the map magnification ratio of active view
The first abbreviation threshold value；By the first abbreviation threshold value, abbreviation is carried out to the spatial data, using the data after abbreviation as
Current abbreviation result；Using the second abbreviation threshold value reciprocal as vector data of the magnification ratio of spatial data formerly cached；
And by the second abbreviation threshold value, abbreviation is carried out to the spatial data, the data after abbreviation are regard as first abbreviation knot
Really.
Preferably, the reception device be disposed for by the luv space data after abbreviation in luv space data
Position and the spatial data formerly cached in position identical original coordinates point of the coordinate points in luv space data
Remove；And determine that the spatial data retained is the incremental data.
Preferably, the send-request unit is configured to be stored with the spatial data formerly cached, in the request of data
Also include the corresponding following view parameter of request incremental data：The amplification of spatial data identification number, the spatial data formerly cached
The positional information of ratio and the coordinate points of the spatial data formerly cached in luv space data；And by the incremental number
According to being inserted into the spatial data formerly cached.
Pass through above-mentioned technical proposal, it is possible to achieve the transmission in progress of the lossless display of spatial data, accomplish adaptive progressive
Transmission, and arbitrarily complicated vector data is during progressive transmission is carried out, can remain vector data in itself and arrow
The correct display of spatial relationship between amount data, enables the spatial data of magnanimity to realize quick transmission and show, it is ensured that number
According to that lossless can show, while reducing volume of transmitted data, the efficiency of transmission of data is improved.
Other features and advantages of the present invention will be described in detail in subsequent embodiment part.
Brief description of the drawings
Accompanying drawing is, for providing a further understanding of the present invention, and to constitute a part for specification, with following tool
Body embodiment is used to explain the present invention together, but is not construed as limiting the invention.In the accompanying drawings：
Fig. 1 is the progressive transmission of spatial data flow chart that the present invention is provided；
Fig. 2 is the simplifying method flow chart for the spatial data that the present invention is provided；And
Fig. 3 (a)-Fig. 3 (d) is Douglas-pula lattice algorithm schematic diagram that the present invention is provided.
Embodiment
The embodiment of the present invention is described in detail below in conjunction with accompanying drawing.It should be appreciated that this place is retouched
The embodiment stated is merely to illustrate and explain the present invention, and is not intended to limit the invention.
Fig. 1 is the progressive transmission of spatial data flow chart that the present invention is provided；Fig. 2 is the spatial data that the present invention is provided
Simplifying method flow chart；And Fig. 3 (a)-Fig. 3 (d) is Douglas-pula lattice algorithm schematic diagram that the present invention is provided.Its
In, during the display of spatial data, its corresponding actual scene is, due to the resolution ratio of view window be it is limited, when
When high-resolution spatial data is shown in view window, the data (coordinate points) for having expressive space data details part are painted
System is in identical pixel, as long as at this moment taking the coordinate points drawn in this pixel to ensure that the lossless of spatial data
Show, coordinate points of other draftings in this pixel can be removed, and therefore, handle spatial data abbreviation according to above-mentioned thought
After be transmitted, show, with the effect shown after abbreviation be in display effect, before abbreviation as.It is empty when map amplifies
Between data display to the number of pixels relatively more (graphics Web publishing that spatial data is shown is big) filled on screen, it is necessary to which more sit
Punctuate carrys out the detail section of expressive space data, as long as these coordinate points (incremental data) are taken from luv space data
And be inserted into corresponding existing spatial data, it still can ensure the lossless display of spatial data.Describe for convenience,
Spatial data to be processed will be needed to be referred to as luv space data, it is necessary to which the coordinate of the spatial data of processing claims in present specification
The original coordinates for luv space data, it is necessary to which the coordinate points of spatial data of processing are referred to as the original of luv space data
Coordinate points, or directly it is referred to as original coordinates point.To achieve these goals, the invention provides a kind of spatial data transmission side
Method, including：S101, request transmitting terminal sends incremental data request and arrives receiving terminal, and the request of data includes active view and put
Vast scale；Receiving terminal described in S102 is analyzed the active view magnification ratio to obtain incremental data and send incremental data
Return the request transmitting terminal；And S103, the request transmitting terminal reception incremental data.
By S101, request transmitting terminal sends incremental data；, will by the active view magnification ratio by S102
Incremental data enters line translation, abbreviation and replacement, so that the request data after being handled, so that request data becomes simple；It is logical
S103 is crossed, request transmitting terminal receives the incremental data caching after the processing.
Preferably, the request transmitting terminal, which receives the incremental data step, also includes：The request Sender side Storage has
Also include the corresponding following view parameter of request incremental data in the spatial data formerly cached, the request of data：Space number
The coordinate points of the magnification ratio of the spatial data according to identification number, formerly cached and the spatial data formerly cached are in luv space
Positional information in data；And the incremental data is inserted into the spatial data formerly cached.
Preferably, the step that the incremental data of the reception is inserted into the spatial data formerly cached includes：Obtain
Take the positional information of the original coordinates point in the incremental data；And according to the positional information by the incremental data
Original coordinates point is inserted into the correspondence position in the spatial data formerly cached.
Preferably, the process incremental data of the reception being inserted into the spatial data formerly cached includes：
Using the magnification ratio of the spatial data formerly cached as the view window magnification ratio in the view control parameter, according to
The original coordinates point of the incremental data and the spatial data formerly cached is converted respectively according to the magnification ratio and obtained
The view coordinate points of the view window；Search corresponding with the view coordinate points that the incremental data original coordinates point transformation is obtained
View window on the view coordinate points of the original coordinates point transformation of spatial data that formerly cache described in pixel identical；By institute
The original coordinates point for stating incremental data is inserted into view window pixel and its phase corresponding to the view coordinate points after the conversion
Behind the original coordinates point of the same spatial data formerly cached；And replace the spatial data formerly cached
Magnification ratio is the active view window magnification ratio in the view control parameter.
In one embodiment, a kind of progressive transmission of spatial data flow, this method is applied to request transmitting terminal,
The situation of the spatial data formerly cached is cached with based on request transmitting terminal, including：S111, obtains the spatial data formerly cached
Magnification ratio；S112, judges whether the magnification ratio of the spatial data formerly cached is less than the active view window
Magnification ratio, if so, then perform step S131, if it is not, then terminating；S113, sends incremental data request, is wrapped in the request
Parameter containing view control, view control parameter now includes：Active view window magnification ratio, search space solid rectangular model
Enclose, ask the magnification ratio of the corresponding spatial data identification number of incremental data and the spatial data formerly cached；S114, receive according to
The incremental data obtained after being analyzed according to the magnification ratio；S115, the incremental data of the reception is inserted into described formerly slow
In the spatial data deposited, the spatial data formerly cached due to now asking transmitting terminal to be cached with, so needing the increasing of reception
Amount data are inserted into the spatial data formerly cached, realize data reconstruction, the data after reconstruction are used as active view window
The data of correspondence display.
In another embodiment, a kind of progressive transmission of spatial data flow includes：S121, receives request and sends
The incremental data request that end is sent, includes the map magnification ratio of active view in the incremental data request；Its number received
According to the magnification ratio that the type of the view control parameter in incremental re-quest is spatial data identification number, the spatial data formerly cached
And positional information of the coordinate points of the spatial data formerly cached in luv space data.When request Sender side Storage has
During the spatial data first cached, the view control parameter includes：Active view window magnification ratio, search space solid rectangular
The magnification ratio of scope, the corresponding spatial data identification number of request incremental data and the spatial data formerly cached.According to request
The corresponding spatial data identification number of incremental data finds the luv space data of request；S122, according to map magnification ratio pair
The spatial data carries out abbreviation, regard the data after abbreviation as abbreviation result；S123, analyzes the abbreviation result, it is determined that symbol
The luv space data for closing increment condition are incremental data；And S124, the incremental data is sent to the request transmitting terminal.
Wherein, the simplifying method that can be used in S122 steps is as follows.Fig. 2 is the simplifying method flow chart of spatial data；
And Fig. 3 (a)-Fig. 3 (d) is Douglas-pula lattice algorithm schematic diagram that the present invention is provided.As shown in Figure 2：The present invention is provided
A kind of spatial data simplifying method, this method includes：S201, sets view control parameter；S202, with set view control
Parameter processed determines the abbreviation threshold value of the initial space data of screen active view window；S203, with the abbreviation threshold value to institute
The original coordinates point for stating initial space data is screened, so as to obtain spatial data after abbreviation.
Wherein, by S201, a control parameter, the selection of convenient abbreviation threshold value below are set to view；Pass through
S202, determines abbreviation threshold value, the basic point for weeding out or retaining as point；By S203, original coordinates point is screened,
So as to obtain the spatial data after abbreviation.
Preferably, the view control parameter includes：The width of the outsourcing rectangle of view window and the outsourcing of view window
The height of rectangle so that abbreviation threshold value can be calculated.
Preferably, determining the abbreviation threshold step of the initial space data of screen current video window includes：S201,
Grid scale and longitudinal ratio are determined according to equation below according to the view control parameter：
Grid scale：DRadioX=(nViewWidth/rcMapBound.Width ()),
Longitudinal ratio：DRadioY=(nViewHeight/rcMapBound.Height ()), or
Grid scale：Double dRadioX=double (nViewWidth/rcMapBound.Width ())；
Longitudinal ratio：Double dRadioY=double (nViewHeight/rcMapBound.Height ())；
Wherein, double (double precision) represents that data precision is at least after decimal point ten；DRadioX is represented in view window
The magnification ratio of initial space data described in X-direction in mouthful, dRadioY represents initial described in Y direction in view window
The magnification ratio of spatial data；NViewWidth represents the width of view window, and nViewHeight represents the height of view window
Degree, rcMapBound represents the rectangular extent of the initial space data shown in view window, and .Width () is represented
The width of view window is obtained .Height () represents to obtain the height of view window；S202, with dRadioX and dRadioY
Any one following value as the initial space data magnification ratio：Minimum value, maximum and average value；S203,
And the abbreviation threshold value of the initial space data is used as using the inverse of the flourishing ratio.
Wherein, make to include the reason for calculating threshold value in this way：We have seen that computer on show map it is big
How much small and information is to be determined by the screen resolution of current computer, and display resolution is exactly the picture shown on current screen
Plain number, that is, weighed by horizontal and vertical pixel.When screen resolution is low, the number of pixel is few, in screen
The information shown on curtain is few, but size is than larger；When screen resolution is high, number of pixels is more, the project shown on screen
It is many, but size is smaller, and the image sensed is also more accurate.When being drawn to spatial data, if its summit spacing is small
It in a pixel size under current resolution, then can be plotted in same pixel, be formed overlapping.By this part summit house
Go to show image and have no effect, while decreasing data volume.Therefore this modified hydrothermal process, chooses spatial data and is showing
In the active view window shown, pixel length representative in the actual coordinates of described spatial data is used as abbreviation
The value of threshold value.
Wherein, engineer's scale is to represent map range than distance diminution on the spot or the degree expanded.Formula is：Engineer's scale=figure
The ratio of upper distance and actual range.Chi is divided into large-scale map, medium scale maps, small scale map three to map in proportion
Class, this is difference map content details and omissions, precision height, can solve a kind of conventional sorting technique of problem degree.And calculating
In the view window of machine display space data, pixel length representative in the actual coordinates of described spatial data
Degree, is thus displaying ratio by abbreviation threshold value quantizing equal to the inverse of magnification ratio of the spatial data in the view window
The reciprocal value of chi, then carry out the calculating and judgement of next step.Separately because of consideration mode of this algorithm to abbreviation threshold value D, without right again
Space between the key element of face shows that the uniformity of topological relation carries out special consideration, therefore we are mainly carried out to line feature abbreviation
Research.
It is further preferred that the view control parameter also includes：What is shown in the view window is described first
The rectangular extent of beginning spatial data, enables two dimension view to take threshold value.
It is further preferred that the view control parameter also includes：Viewpoint parameter and projective parameter.
Wherein, the viewpoint parameter includes：Position of the viewpoint in world coordinate system, the target location observed by viewpoint with
And the upward vector of virtual camera；And the projective parameter includes：Rectangular projection parameter and perspective projection parameter, make three-dimensional
View can take threshold value
In one embodiment, the abbreviation threshold value is screened to the original coordinates point of the initial space data
Method includes：The each points of the initial space data is calculated to the first point and the straight line of tail point for connecting the initial space data
Distance；The longest distance calculated is compared with default threshold value, if the longest distance is more than the threshold value, retains straight from this
The maximum point of linear distance is the first retention point；First retention point is set to the tail point and tail point of the first point respectively
First point, repeat above-mentioned two step, obtain the second retention point；First retention point is set to the first point respectively
The first point of tail point and second retention point, second retention point is set to the first point of the tail point, repeats preceding two
Individual step, until obtaining all retention points；And it is used as abbreviation using the first point, tail point and resulting all retention points
Spatial data afterwards.
Wherein it is possible to realized using Douglas-pula lattice algorithm, Douglas-pula lattice algorithm be from entirety to
Part is from coarse to fine to determine to need the process of retention point after curve compression, with translation, rotation, consistency, have simultaneously
The given curve advantage consistent with compression result after limit difference.As shown in Fig. 2 a line is connected to the first and last end points of each curve,
The distance for arriving the straight line a little is sought, and finds out maximum range value (being represented below with dmax), (D is used below with dmax and threshold value
Represent) compare：If the intermediate point on dmax ＜ D, this curve is all cast out；If dmax >=D, retain the corresponding coordinates of dmax
Point, and curve is divided into two parts using the point as boundary, this method is reused to this two parts.The detailed step of algorithm is as follows：
S301, straight line is virtually connected in curve head and the tail point-to-point transmission, obtains remaining each point to the distance of the straight line, such as Fig. 3 (a).S302, choosing
Its maximum is compared with threshold value, if more than threshold value, the point maximum from the air line distance retains, otherwise by between straight line two-end-point
Each point is all cast out, such as Fig. 3 (b), the 4th point of reservation.S303, according to the point retained, is divided into two parts processing by known curve,
The operation of the 1st, 2 steps is repeated, iterative operation is still selected and compared apart from the maximum with threshold value, accepted or rejected successively, can cast out until without point,
The curve point coordinates for meeting given accuracy limit difference is finally obtained, such as Fig. 3 (c) and Fig. 3 (d) retain and at the 6th point at the 7th point successively, give up
Other points are removed, that is, complete the abbreviation of line.
In another embodiment, it is to be pre-processed first that opposite key element, which carries out abbreviation process, generates equivalent line number
According to the actually process of data recombination.For non-topology data, because common edge does not have any specific identifier, it is necessary to whole
Search common edge in the range of individual spatial data, by its from polygon data it is independent, set up metadata.For accurate description
Figure originally, it is necessary to set up the index of these metadata.Its basic step is as follows：For two polygon A, B, it is first determined whether
Whether boundary rectangle intersects, if non-intersect, is searched without following common edge and data prediction is operated.Conversely, using deep
Degree search matching method, chooses polygon mono- seed point of A, then looks for coordinate identical point on polygon B, fixed according still further to one
The other identical points of direction search matching.
Wherein, planar graphical element is surrounded by one or more threadlike graph key element, and its basis is also threadlike graph key element,
Face key element can be split as two lines key element, according to line feature using the Far Left and rightmost on face key element border as starting point
Abbreviation algorithm carries out abbreviation to two lines key element, so as to realize the coordinate abbreviation of opposite key element.But over there key element abbreviation when,
Discounting for the display topological relation between spatial data, it will cause original face key element to show that topological relation is destroyed, example
Such as, two face key elements with common edge, the correlation between key element is not accounted in abbreviation, during compression simply according to will
Inconsistent after the boundary compression of two neighboring area target show is occurred in common edge independent process by the characteristics of element itself
As occurring crack at public boundary, it shows that topological relation is destroyed.
Wherein, over there key element abbreviation when, special processing must be used to polygonal common edge and common node, to prevent
Only case above occurs.The basic ideas of face key element abbreviation are：S311, the preprocessing process of opposite key element extracts adjacent polygon
The common edge of shape, equivalent line number evidence is generated according to certain logical construction；S312, utilizes Douglas-pula lattice algorithm pair
Equivalent line data carry out abbreviation；S313, abbreviation is finished, according to the indexed sequential of generation equivalent data, rebuilds face factor data, and
Stored according to original data format.
In progressive transmission of spatial data disclosed in the present embodiment, to the analysis process foundation incremental data of spatial data
Map magnification ratio in request is carried out, i.e., based on the actual displayed view window for asking transmitting terminal, it is achieved thereby that obtaining
The incremental data obtained can carry out lossless display in request transmitting terminal, while being only transmitted incremental data, be greatly reduced
Volume of transmitted data, improves data transmission efficiency.
To achieve these goals, the invention provides a kind of spatial data progressive transmission device, described device includes please
Dispensing device and reception device are asked, wherein：The send-request unit is configured to send incremental data request to the reception dress
Put, wherein, the request of data includes active view magnification ratio；The reception device is configured to put the active view
Vast scale is analyzed to obtain incremental data and the incremental data is sent back into the send-request unit；And the request hair
Device is sent to be configured to receive the incremental data.
Preferably, the reception device is configured to carry out abbreviation to the spatial data by the view magnification ratio；
And the luv space data of increment condition are determined for compliance with for the incremental data.
Preferably, the reception device is configured to：Vector data is used as using the inverse of the map magnification ratio of active view
The first abbreviation threshold value；By the first abbreviation threshold value, abbreviation is carried out to the spatial data, using the data after abbreviation as
Current abbreviation result；Using the second abbreviation threshold value reciprocal as vector data of the magnification ratio of spatial data formerly cached；
And by the second abbreviation threshold value, abbreviation is carried out to the spatial data, the data after abbreviation are regard as first abbreviation knot
Really.
Preferably, the reception device be disposed for by the luv space data after abbreviation in luv space data
Position and the spatial data formerly cached in position identical original coordinates point of the coordinate points in luv space data
Remove；And determine that the spatial data retained is the incremental data.
Preferably, the send-request unit is configured to be stored with the spatial data formerly cached, in the request of data
Also include the corresponding following view parameter of request incremental data：The amplification of spatial data identification number, the spatial data formerly cached
The positional information of ratio and the coordinate points of the spatial data formerly cached in luv space data；And by the incremental number
According to being inserted into the spatial data formerly cached.
The preferred embodiment of the present invention is described in detail above in association with accompanying drawing, still, the present invention is not limited to above-mentioned reality
The detail in mode is applied, in the range of the technology design of the present invention, a variety of letters can be carried out to technical scheme
Monotropic type, these simple variants belong to protection scope of the present invention.
It is further to note that each particular technique feature described in above-mentioned embodiment, in not lance
In the case of shield, can be combined by any suitable means, in order to avoid unnecessary repetition, the present invention to it is various can
The combination of energy no longer separately illustrates.
In addition, various embodiments of the present invention can be combined randomly, as long as it is without prejudice to originally
The thought of invention, it should equally be considered as content disclosed in this invention.
Claims (8)
1. a kind of progressive transmission of spatial data, it is characterised in that this method includes：
Ask transmitting terminal to send incremental data request and arrive receiving terminal, the request of data includes active view magnification ratio；
The receiving terminal is analyzed the active view magnification ratio to obtain incremental data and send back incremental data described
Ask transmitting terminal；And
The request transmitting terminal receives the incremental data, wherein
The step of receiving terminal analysis obtains incremental data includes：
The receiving terminal carries out abbreviation by the view magnification ratio to the spatial data；And
The luv space data for being determined for compliance with increment condition are the incremental data；And, wherein
The process that the receiving terminal carries out abbreviation by the view magnification ratio to the spatial data includes：
Using the first abbreviation threshold value reciprocal as vector data of the map magnification ratio of active view；
By the first abbreviation threshold value, abbreviation is carried out to the spatial data, the data after abbreviation are regard as current abbreviation knot
Really；
Using the second abbreviation threshold value reciprocal as vector data of the magnification ratio of spatial data formerly cached；And
By the second abbreviation threshold value, abbreviation is carried out to the spatial data, the data after abbreviation are regard as first abbreviation knot
Really；
Wherein, abbreviation is carried out to the spatial data including following by the first abbreviation threshold value or the second abbreviation threshold value
Threshold value in step, wherein following steps is the first abbreviation threshold value or the second abbreviation threshold value：
Step one, calculate each point of the spatial data to the connection spatial data first point and tail point straight line distance；
Step 2, the longest distance calculated is compared with the threshold value, if the longest distance is more than the threshold value, retains straight from this
The maximum point of linear distance is the first retention point；First retention point is set to the tail point and tail point of the first point respectively
First point, repeat the step one and the step 2, obtain the second retention point；First retention point is set to respectively
The tail point of the first point and the first point of second retention point, second retention point are set to the first point of the tail point, weight
The step one and the step 2 are carried out again, until obtaining all retention points；And with the first point, tail point and gained
All retention points arrived are as the data after the abbreviation.
2. transmission method according to claim 1, it is characterised in that the view coordinate for being determined for compliance with increment condition is corresponding
Luv space data include for the process of the incremental data：
By in the position in the luv space data after abbreviation in luv space data and the spatial data formerly cached
Position identical original coordinates point of the coordinate points in luv space data is removed；And
It is determined that the spatial data retained is the incremental data.
3. transmission method according to claim 1, it is characterised in that the request transmitting terminal receives the incremental data step
Suddenly also include：
The request Sender side Storage, which has, also includes request incremental data pair in the spatial data formerly cached, the request of data
The following view parameter answered：Spatial data identification number, the magnification ratio of the spatial data formerly cached and the sky formerly cached
Between data positional information of the coordinate points in luv space data；And
The incremental data is inserted into the spatial data formerly cached.
4. transmission method according to claim 3, it is characterised in that the incremental data of the reception is inserted into described first
Step in the spatial data of caching includes：
Obtain the positional information of the original coordinates point in the incremental data；And
The original coordinates point in the incremental data is inserted into the spatial data formerly cached according to the positional information
In correspondence position.
5. transmission method according to claim 4, it is characterised in that by the incremental data of the reception be inserted into it is described
Process in the spatial data first cached includes：
It regard the magnification ratio of the spatial data formerly cached as the view window amplification ratio in the view control parameter
Example, converts the original coordinates point of the incremental data and the spatial data formerly cached according to the magnification ratio respectively
Obtain the view coordinate points of the view window；
Search identical with pixel in the corresponding view window of view coordinate points that the incremental data original coordinates point transformation is obtained
The spatial data formerly cached original coordinates point transformation view coordinate points；
The original coordinates point of the incremental data is inserted into the view window picture corresponding to the view coordinate points after the conversion
Behind the original coordinates point of the same spatial data formerly cached of element；And
The magnification ratio for replacing the spatial data formerly cached is that the active view window in the view control parameter is put
Vast scale.
6. a kind of spatial data progressive transmission device, it is characterised in that described device includes send-request unit and reception device,
Wherein：
The send-request unit is configured to send incremental data request to the reception device, wherein, in the request of data
Including active view magnification ratio；
The reception device is configured to active view magnification ratio analysis obtain incremental data and by the incremental number
According to sending back the send-request unit；And
The send-request unit is configured to receive the incremental data, wherein
The reception device is configured to carry out abbreviation to the spatial data by the view magnification ratio；And
The luv space data for being determined for compliance with increment condition are the incremental data；And
The reception device is configured to：
Using the first abbreviation threshold value reciprocal as vector data of the map magnification ratio of active view；
By the first abbreviation threshold value, abbreviation is carried out to the spatial data, the data after abbreviation are regard as current abbreviation knot
Really；
Using the second abbreviation threshold value reciprocal as vector data of the magnification ratio of spatial data formerly cached；And
By the second abbreviation threshold value, abbreviation is carried out to the spatial data, the data after abbreviation are regard as first abbreviation knot
Really；
Wherein, abbreviation is carried out to the spatial data including following by the first abbreviation threshold value or the second abbreviation threshold value
Threshold value in step, wherein following steps is the first abbreviation threshold value or the second abbreviation threshold value：
Step one, calculate each point of the spatial data to the connection spatial data first point and tail point straight line distance；
Step 2, the longest distance calculated is compared with the threshold value, if the longest distance is more than the threshold value, retains straight from this
The maximum point of linear distance is the first retention point；First retention point is set to the tail point and tail point of the first point respectively
First point, repeat the step one and the step 2, obtain the second retention point；First retention point is set to respectively
The tail point of the first point and the first point of second retention point, second retention point are set to the first point of the tail point, weight
The step one and the step 2 are carried out again, until obtaining all retention points；And with the first point, tail point and gained
All retention points arrived are as the data after the abbreviation.
7. device according to claim 6, it is characterised in that the reception device is disposed for will be original after abbreviation
Position in spatial data in luv space data is with coordinate points in the spatial data formerly cached in luv space number
Position identical original coordinates point in is removed；And
It is determined that the spatial data retained is the incremental data.
8. device according to claim 6, it is characterised in that the send-request unit is configured to the first caching that is stored with
Spatial data, the corresponding following view parameter of request incremental data is also included in the request of data：Spatial data identification number,
The coordinate points of the magnification ratio of the spatial data formerly cached and the spatial data formerly cached are in luv space data
Positional information；And
The incremental data is inserted into the spatial data formerly cached.
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| CN101827097A (en) * | 2010-01-07 | 2010-09-08 | 董福田 | Vector data self-adaption progressive transmission method based on spatial entity view model |
| CN102044089A (en) * | 2010-09-20 | 2011-05-04 | 董福田 | Method for carrying out self-adaption simplification, gradual transmission and rapid charting on three-dimensional model |
| CN102096945A (en) * | 2010-01-07 | 2011-06-15 | 董福田 | Method and device for progressive transmission of spatial data |
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| CN101246597A (en) * | 2007-11-30 | 2008-08-20 | 北京师范大学 | Method for commercial scale vector map data gradual transmission and dynamic reconstruction |
| CN101827097A (en) * | 2010-01-07 | 2010-09-08 | 董福田 | Vector data self-adaption progressive transmission method based on spatial entity view model |
| CN102096945A (en) * | 2010-01-07 | 2011-06-15 | 董福田 | Method and device for progressive transmission of spatial data |
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