CN103186923A - Method and device of displaying electronic map and terminal device - Google Patents

Abstract

The invention discloses a method and device of displaying an electronic map and a terminal device. The method includes the following steps: obtaining the height, the width and a three dimensional perspective angle of the electronic map; according to the height, the width and the three dimensional perspective angle of the electronic map, determining a pin-hole imaging module for three dimensional perspective projection processing; using the pin-hole imaging module to conduct the three dimensional perspective projection processing on the electronic map, and obtaining a perspective projection coordinate of the electronic map; according to the perspective projection coordinate of the electronic map, displaying the electronic map. According to the technical scheme, the method and device of displaying the electronic map solves the problem that in the prior art, a three dimensional electronic map with a real three dimensional perspective effect can not be displayed to users when the three dimensional perspective angle of the electronic map is not 0.

Description

Electronic chart exhibiting method, device and terminal device

Technical field

The present invention relates to the electronic map technique field, relate in particular to a kind of electronic chart exhibiting method, device and terminal device.

Background technology

Along with the development of computerized mapping, the conventional paper map is replaced by electronic chart widely, and is widely used at various intelligent terminals.Electronic chart can be divided into bitmap map and map vector again, and what wherein map vector was a large amount of is applied in all kinds of GPS (GPS, the Global Positioning System) navigator.If electronic chart is map vector, then electronic chart is made up of a large amount of coordinate points, the corresponding coordinate figure of each coordinate points when representing electronic chart to the user, can be drawn electronic chart at terminal device (for example navigator) according to the coordinate figure of each coordinate points on the electronic chart.

Terminal device can carry out electronic chart playing up of two dimension (2D, Second Dimensions) mode, represents the electronic chart of two dimension to the user.In order to pursue display effect more true to nature, a lot of terminal devices carry out playing up of three-dimensional (3D, Three Dimensions) mode with electronic chart, represent three-dimensional electronic chart to the user.

In the prior art, the modal technology of utilizing d engine to carry out 3D processing has open graphic package interface (OpenGL, Open Graphics Library) and the graphic package interface of the opening of embedded system (OpenGL ES, OpenGL for Embedded Systems) etc.Yet the operating system platform of these Technology Need terminal devices is supported the OpenGL interface, yet a lot of operating system platforms are not supported the OpenGL interface, and the OpenGL interface that provides of different operating system platform is based on the development language of operating system platform itself, it is multiplexing to be difficult to code so when cross-platform application, the existing complexity of utilizing d engine to carry out the 3D processing technology is very high in addition, hardware requirement to terminal device is very high, and the workload during processing is very big.

At the problems referred to above, prior art has proposed a kind of pseudo-three-dimensional processing method, when terminal device need represent the electronic chart with 3-D effect to the user, can carry out certain conversion to each two-dimensional coordinate in the electronic chart earlier, the result who obtains according to conversion draws electronic chart then, just can obtain having the electronic chart of 3-D effect.

Terminal device represents three-dimensional electronic chart to the user, angle between electronic chart and display plane (yet can be called the three-dimensional perspective angle) is not 0, it is observer's sight line and when being not orthogonal to electronic chart, in the electronic three-dimensional map that terminal device represents, the ratio of distant objects should be less than the ratio (near big and far smaller) of near objects, and electronic chart that then should three-dimensional has real three-dimensional perspective effect.But if terminal device adopts above-mentioned pseudo-three-dimensional processing method to represent three-dimensional electronic chart to the user, then the three-dimensional perspective angle at electronic chart is not 0 o'clock, the electronic chart of the three-dimensional that terminal device represents does not have the near big and far smaller effect of scenery, and namely above-mentioned pseudo-three-dimensional processing method can't be realized real three-dimensional perspective effect.

Summary of the invention

The embodiment of the invention provides a kind of electronic chart exhibiting method, device and terminal device, in order to solve prior art when the three-dimensional perspective angle of electronic chart is not 0, can't represent the problem of the electronic three-dimensional map with true three-dimensional transparent effect to the user.

Embodiment of the invention technical scheme is as follows:

A kind of electronic chart exhibiting method, the method comprising the steps of: the height of electron gain map, width and three-dimensional perspective angle; According to height, width and the three-dimensional perspective angle of electronic chart, be identified for the pinhole imaging system model of three-dimensional perspective projection process; Use described pinhole imaging system model, described electronic chart is carried out the three-dimensional perspective projection process, obtain the perspective projection coordinate of described electronic chart; Perspective projection coordinate according to described electronic chart represents described electronic chart.

A kind of electronic chart demonstration device comprises: obtain the unit, be used for height, width and the three-dimensional perspective angle of electron gain map; The model determining unit is used for height, width and three-dimensional perspective angle according to electronic chart, is identified for the pinhole imaging system model of three-dimensional perspective projection process; Three-dimensional perspective projection process unit is used for using described pinhole imaging system model, and described electronic chart is carried out the three-dimensional perspective projection process, obtains the perspective projection coordinate of described electronic chart; Electronic chart represents the unit, is used for the perspective projection coordinate according to described electronic chart, represents described electronic chart.

A kind of terminal device comprises above-mentioned electronic chart demonstration device.

In the embodiment of the invention technical scheme, if need represent electronic chart to the user, the then at first height of electron gain map, width and three-dimensional perspective angle, then according to height, width and the three-dimensional perspective angle of electronic chart, be identified for the pinhole imaging system model of three-dimensional perspective projection process, the pinhole imaging system model that use is determined, described electronic chart is carried out the three-dimensional perspective projection process, obtain the perspective projection coordinate of described electronic chart, each perspective projection coordinate that last basis obtains represents described electronic chart.Therefore, embodiment of the invention technical scheme adopts the pinhole imaging system model based on the pinhole imaging system principle that electronic chart is carried out the three-dimensional perspective projection process, wherein the pinhole imaging system model is that height, width and three-dimensional perspective angle according to electronic chart determined, even the three-dimensional perspective angle of electronic chart is not 0 so, also can in the electronic chart that finally represents to the user, present near big and far smaller three-dimensional perspective effect, namely represent the electronic three-dimensional map with true three-dimensional transparent effect to the user.

Description of drawings

Fig. 1 is in the embodiment of the invention, electronic chart exhibiting method schematic flow sheet;

Fig. 2 is in the embodiment of the invention, pinhole imaging system model synoptic diagram;

Fig. 3 is in the embodiment of the invention, the coordinate system synoptic diagram in the imaging surface;

Fig. 4 is in the embodiment of the invention, the isosceles triangle synoptic diagram;

Fig. 5 is in the embodiment of the invention, the screen of pinhole imaging system model to aperture apart from synoptic diagram;

Fig. 6 is in the embodiment of the invention, three-dimensional perspective projection theory synoptic diagram;

Fig. 7 is in the embodiment of the invention, three-dimensional perspective projection theory synoptic diagram;

Fig. 8 is in the embodiment of the invention, three-dimensional perspective projection theory synoptic diagram;

Fig. 9 is in the embodiment of the invention, electronic chart demonstration device structural representation.

Embodiment

At length set forth to the main realization principle of embodiment of the invention technical scheme, embodiment and to the beneficial effect that should be able to reach below in conjunction with each accompanying drawing.

As shown in Figure 1, be the electronic chart exhibiting method schematic flow sheet that the embodiment of the invention proposes, its concrete treatment scheme is as follows:

Step 11, the height of electron gain map, width and three-dimensional perspective angle;

When terminal device is wanted to represent electronic chart to the user, size that can first electron gain map (height and width) and three-dimensional perspective angle.Wherein, described three-dimensional perspective angle refers to the angle between electronic chart and the display plane, and initial value can be set to 0, and namely the three-dimensional perspective angle is 0.In actual applications, described three-dimensional perspective angle can be reset by the user.The sight that the user arranges the three-dimensional perspective angle comprises:

The user uses terminal device to represent before the electronic chart, set the three-dimensional perspective angle earlier, the angle value that this moment, terminal device was set the user saves as the three-dimensional perspective angle of electronic chart, perhaps, the user is using terminal device to represent in the process of electronic chart, adjust angle between electronic chart and the display plane in real time according to the needs of oneself, terminal device obtains the three-dimensional perspective angle after the user adjusts in real time.

Step 12 according to height, width and the three-dimensional perspective angle of electronic chart, is identified for the pinhole imaging system model of three-dimensional perspective projection process;

At first introduce the pinhole imaging system model that is used for the three-dimensional perspective projection process.

The pinhole imaging system model as shown in Figure 2, can regard a sealing rectangular parallelepiped that is used for doing pinhole imaging system as, the aperture of imaging is in the middle of rectangular parallelepiped, because the size of aperture is far smaller than the size of pinhole imaging system model, therefore aperture can be regarded as a point on the face, the plane at aperture place can be called the hole face, aperture is positioned at the center (being two intersection of diagonal places of hole face) of hole face, (the i.e. equal in length of two little rectangular parallelepipeds of two little rectangular parallelepipeds about the hole face is equally divided into the sealing rectangular parallelepiped, width equates, highly equal), one of them little rectangular parallelepiped (for example little rectangular parallelepiped on the left side) is used for placing the electronic chart that need represent, and another little rectangular parallelepiped (for example You Bian little rectangular parallelepiped) is used for imaging.

In Fig. 2, can be called the imaging awl for the inner rectangular pyramid body of the little rectangular parallelepiped (the little rectangular parallelepiped on the left side) of placing the electronic chart that need represent in the sealing rectangular parallelepiped, the summit of imaging awl is aperture, aperture is four limits of imaging awl with the line on four summits of leftmost of sealing rectangular parallelepiped, and the bottom surface of imaging awl is leftmost of sealing rectangular parallelepiped.The imaging awl is effective imaging region in the sealing rectangular parallelepiped.

In Fig. 2, rightmost of the sealing rectangular parallelepiped can be called screen, is the screen of imaging, and the arbitrary section in the imaging awl all can be imaged on the screen.The cross section parallel with screen can be called imaging surface in the imaging awl, and imaging surface is the face at the coordinate points place on the cross section of electronic chart in the imaging awl, as shown in Figure 3, is the coordinate system synoptic diagram in the imaging surface.

In Fig. 2, aperture is made as F to the distance of screen, aperture is made as f to the distance of imaging surface, the coordinate of coordinate points on electronic chart be (x, y), coordinate on the imaging surface of correspondence be (x ', y '), this coordinate points is through behind pinhole imaging system, the coordinate of imaging point on screen be (Xt ', Yt '), F, f, x ', y ', Xt ', Yt ' satisfy following relation so:

$\frac{x^{\′}}{{\mathrm{Xt}}^{\′}}=\frac{y^{\′}}{{\mathrm{Yt}}^{\′}}=\frac{f}{F}$

When terminal device need represent electronic chart, obtain height, width and the three-dimensional perspective angle of this electronic chart, the width of establishing electronic chart is W, highly is H, and the three-dimensional perspective angle is a, can but be not limited to adopt following manner to determine the pinhole imaging system model:

The width W of electronic chart is set to the width of pinhole imaging system model, the height H of electronic chart is set to the height of pinhole imaging system model, then according to three-dimensional perspective angle a and height H, the aperture of determining the pinhole imaging system model to screen apart from F, the length of pinhole imaging system model is 2F.

Determine that the screen of aperture of pinhole imaging system model is to apart from F the time, obtain isosceles triangle earlier, the drift angle angle of this isoceles triangle shape equals three-dimensional perspective angle a, the waist length of this isoceles triangle shape equals the height H of electronic chart, as shown in Figure 4, obtain the intersection point of the base extended line of the vertical centering control separated time of waist of this isoceles triangle shape and this isoceles triangle shape, as shown in Figure 5, with the central point of the waist of isosceles triangle and the distance between the described intersection point, the screen of confirming as the aperture of pinhole imaging system model arrives apart from F, and the length of pinhole imaging system model is 2F.

When adopting above-mentioned algorithm to determine that the screen of the aperture of pinhole imaging system model arrives apart from F, effective span of three-dimensional perspective angle a is 0～60 degree, and the span of F is F＞H * sin (a).

Step 13 is used described pinhole imaging system model, and described electronic chart is carried out the three-dimensional perspective projection process, obtains the perspective projection coordinate of described electronic chart;

Use described pinhole imaging system model, described electronic chart is carried out the three-dimensional perspective projection process can be regarded as visually described electronic chart is put into the pinhole imaging system model as shown in Figure 6, angle between leftmost of electronic chart and pinhole imaging system model is the three-dimensional perspective angle a of electronic chart, when the three-dimensional perspective angle of electronic chart is 0, the size of this electronic chart is the size of the electronic chart that terminal device finally represents to the user, as can be seen from Figure 6, when the three-dimensional perspective angle of electronic chart was a, the size in the cross section of electronic chart in imaging awl was the size of the electronic chart that terminal device finally represents to the user.

Terminal device is determined the cross section of electronic chart in the imaging awl of pinhole imaging system model earlier, then according to the pinhole imaging system principle, calculate the coordinate of each coordinate points on the screen of pinhole imaging system model on this cross section in the pinhole imaging system model, the coordinate that obtains is the perspective projection coordinate of described electronic chart.

As shown in Figure 6, the maximal value of the coordinate x of coordinate points on the described cross section on the imaging surface of correspondence is identical with the maximal value of the coordinate x of coordinate points on screen, the minimum value of the coordinate x of coordinate points on the described cross section on the imaging surface of correspondence is identical with the minimum value of the coordinate x of coordinate points on screen, same, the maximal value of the coordinate y of coordinate points on the described cross section on the imaging surface of correspondence is identical with the maximal value of the coordinate y of coordinate points on screen, the minimum value of the coordinate y of coordinate points on the described cross section on the imaging surface of correspondence is identical with the minimum value of the coordinate y of coordinate points on screen, this has just set up the inner link between two-dimentional electronic chart and the three-dimensional electronic chart, and this inner link is when making electronic chart with two dimension be upgraded to three-dimensional electronic chart, only need to consider that the projective transformation problem gets final product, and has simplified the difficulty and the workload that represent three-dimensional electronic chart largely.

Coordinate points on the cross section may be the two-dimensional coordinate point, introduces the specific implementation flow process of calculating the coordinate of these coordinate points on screen below.

Step 1 is calculated the coordinate on the imaging surface of each coordinate points in correspondence on the cross section of electronic chart in the imaging awl.

Terminal device is at first according to the latitude and longitude coordinates of each coordinate points on the electronic chart, determine each coordinate points at the screen coordinate on the electronic chart (hereinafter to be referred as the coordinate of coordinate points on electronic chart), if the coordinate of certain coordinate points on electronic chart is (x, y), when the three-dimensional perspective angle of electronic chart is a, in the pinhole imaging system model, the coordinate of this coordinate points in the imaging surface of correspondence be (x ', y '), as shown in Figure 7, wherein, x '=x, the computation process of y ' can but be not limited to following:

Aperture in the pinhole imaging system model is F to the distance of screen, and aperture is f to the distance of the imaging surface of this coordinate points correspondence, wherein:

F-f＝y×sin(a) (1)

By formula (1) as can be known:

f＝F-y×sin(a) (2)

The length of side of the imaging surface of this coordinate points correspondence is h ', then:

$\frac{h^{\′}}{H}=\frac{f}{F}---\left(3\right)$

By formula (2) and formula (3) as can be known:

$h^{\′}=\frac{H\×[F-y\×\sin \left(a\right)]}{F}---\left(4\right)$

As shown in Figure 7:

$\frac{H}{2}-y\×\cos \left(a\right)=\frac{h^{\′}}{2}-y^{\′}---\left(5\right)$

By formula (4) and formula (5) as can be known:

$y^{\′}=\frac{H\×[F-y\×\sin \left(a\right)]}{2F}-\frac{H}{2}+y\×\cos \left(a\right)---\left(6\right)$

Step 2 according to the coordinate of each coordinate points on the imaging surface of correspondence, is calculated the coordinate of each coordinate points on screen.

In the pinhole imaging system model, the coordinate of coordinate points on screen is (Xt ', Yt '), wherein:

${\mathrm{Yt}}^{\′}=y^{\′}\×\frac{F}{f}---\left(7\right)$

${\mathrm{Xt}}^{\′}=x^{\′}\×\frac{F}{f}---\left(8\right)$

By formula (2) and formula (7) as can be known:

${\mathrm{Yt}}^{\′}=y^{\′}\×\frac{F}{F-y\×\sin \left(a\right)}---\left(9\right)$

By formula (2) and formula (8) as can be known:

${\mathrm{Xt}}^{\′}=x^{\′}\×\frac{F}{F-y\×\sin \left(a\right)}---\left(10\right)$

In above-mentioned processing procedure, above-mentioned coordinate points is the two-dimensional coordinate point, and so above-mentioned processing procedure also can be called tripleplane's algorithm of two-dimensional coordinate.

In addition, coordinate points on the cross section of electronic chart in the imaging awl also may be three-dimensional coordinate point, be that coordinate points is except having horizontal ordinate and ordinate, also has ordinate, namely has height value, as shown in Figure 8, introduce the specific implementation flow process of calculating the coordinate of these coordinate points on screen below.

Step 1 is calculated the coordinate on the imaging surface of each coordinate points in correspondence on the cross section of electronic chart in the imaging awl.

If the coordinate of certain coordinate points on electronic chart is (x, y, z), wherein z is the ordinate of this coordinate points on electronic chart, when the three-dimensional perspective angle of electronic chart is a, in the pinhole imaging system model, the coordinate of this coordinate points in the imaging surface of correspondence be (x ", y "), wherein, the computation process of x "=x, y " can but be not limited to following:

Aperture in the pinhole imaging system model is F to the distance of screen, and aperture is f ' to the distance of the imaging surface of this coordinate points correspondence, and aperture is f to the distance of the imaging surface at the two-dimensional coordinate point place of this three-dimensional coordinate point correspondence, and f satisfies formula (2), wherein:

f-f′＝z×cos(a) (11)

By formula (2) and formula (11) as can be known:

f′＝F-y×sin(a)-z×cos(a) (12)

The length of side of the imaging surface of this coordinate points correspondence is h ", then:

$h^{\′\′}/H=\frac{f^{\′}}{F}---\left(13\right)$

By formula (12) and formula (13) as can be known:

$h^{\′\′}=\frac{F-y\×\sin \left(a\right)-z\×\cos \left(a\right)}{F}\×H---\left(14\right)$

As shown in Figure 7:

$\frac{H}{2}-y\×\cos \left(a\right)=\frac{h^{\′\′}}{2}-z\×\sin \left(a\right)-y^{\′\′}---\left(15\right)$

By formula (14) and formula (15) as can be known:

$y^{\′\′}=\frac{F-y\×\sin \left(a\right)-z\×\cos \left(a\right)}{2F}\×H-z\×\sin \left(a\right)-\frac{H}{2}+y\×\cos \left(a\right)---\left(16\right)$

Step 2 according to the coordinate of each coordinate points on the imaging surface of correspondence, is calculated the coordinate of each coordinate points on screen.

In the pinhole imaging system model, the coordinate of coordinate points on screen be (Xt ", Yt "), wherein:

${\mathrm{Yt}}^{\′\′}=y^{\′\′}\×\frac{F}{f^{\′}}---\left(17\right)$

${\mathrm{Xt}}^{\′\′}=x^{\′\′}\×\frac{F}{f^{\′}}---\left(18\right)$

By formula (12) and formula (17) as can be known:

${\mathrm{Yt}}^{\′\′}=y^{\′\′}\×\frac{F}{F-y\×\sin \left(a\right)-z\×\cos \left(a\right)}---\left(19\right)$

By formula (12) and formula (18) as can be known:

${\mathrm{Xt}}^{\′\′}=x^{\′\′}\×\frac{F}{F-y\×\sin \left(a\right)-z\×\cos \left(a\right)}---\left(20\right)$

Because in electronic chart, some building piece has certain height, so its coordinate points is three-dimensional coordinate point, and the embodiment of the invention is when representing electronic chart, adopt said method that electronic chart is carried out the three-dimensional perspective projection process, can demonstrate these three-dimensional building pieces visually.

In above-mentioned processing procedure, above-mentioned coordinate points is three-dimensional coordinate point, and so above-mentioned processing procedure also can be called tripleplane's algorithm of three-dimensional coordinate.

Step 14, the perspective projection coordinate according to described electronic chart represents described electronic chart.

By above-mentioned processing procedure as can be known, in the embodiment of the invention technical scheme, if need represent electronic chart to the user, the then at first height of electron gain map, width and three-dimensional perspective angle, then according to height, width and the three-dimensional perspective angle of electronic chart, be identified for the pinhole imaging system model of three-dimensional perspective projection process, the pinhole imaging system model that use is determined, described electronic chart is carried out the three-dimensional perspective projection process, obtain the perspective projection coordinate of described electronic chart, the perspective projection coordinate that last basis obtains represents described electronic chart.Therefore, embodiment of the invention technical scheme adopts the pinhole imaging system model based on the pinhole imaging system principle that electronic chart is carried out the three-dimensional perspective projection process, wherein the pinhole imaging system model is that height, width and three-dimensional perspective angle according to electronic chart determined, even the three-dimensional perspective angle of electronic chart is not 0 so, also can in the electronic chart that finally represents to the user, present near big and far smaller three-dimensional perspective effect, namely represent the electronic three-dimensional map with true three-dimensional transparent effect to the user.

Corresponding with above-mentioned electronic chart exhibiting method, the embodiment of the invention proposes a kind of electronic chart demonstration device, and its structure comprises as shown in Figure 9:

Obtain unit 91, be used for height, width and the three-dimensional perspective angle of electron gain map;

Model determining unit 92 is used for height, width and three-dimensional perspective angle according to electronic chart, is identified for the pinhole imaging system model of three-dimensional perspective projection process;

Three-dimensional perspective projection process unit 93 is used for using described pinhole imaging system model, and described electronic chart is carried out the three-dimensional perspective projection process, obtains the perspective projection coordinate of described electronic chart;

Electronic chart represents unit 94, is used for the perspective projection coordinate according to described electronic chart, represents described electronic chart.

Preferably, model determining unit 92 specifically comprises:

Subelement highly is set, and the height that is used for electronic chart is set to the height of pinhole imaging system model;

Width arranges subelement, and the width that is used for electronic chart is set to the width of pinhole imaging system model;

Length is determined subelement, is used for height and three-dimensional perspective angle according to electronic chart, determines the length of pinhole imaging system model.

More preferably, length determines that subelement specifically comprises:

The triangle acquisition module is used for obtaining isosceles triangle, and the drift angle angle of described isosceles triangle equals described three-dimensional perspective angle, and the waist length of described isosceles triangle equals the height of described electronic chart;

The intersection point acquisition module is used for obtaining the intersection point of the base extended line of the vertical centering control separated time of waist of described isosceles triangle and described isosceles triangle;

The length acquisition module is used for obtaining the length of pinhole imaging system model according to the central point of the waist of described isosceles triangle and the distance between the described intersection point.

Preferably, three-dimensional perspective projection process unit 93 specifically comprises:

Subelement is determined in the cross section, is used for determining the cross section of described electronic chart in the imaging awl of described pinhole imaging system model;

The coordinate Calculation subelement is used for calculating the coordinate of each coordinate points on the screen of pinhole imaging system model on the described cross section, and the coordinate that obtains is the perspective projection coordinate of described electronic chart.

More preferably, the coordinate Calculation subelement specifically comprises:

The first coordinate Calculation module is used for calculating the coordinate of each coordinate points on the imaging surface of correspondence on the described cross section;

The second coordinate Calculation module is used for according to the coordinate of each coordinate points on the imaging surface of correspondence, calculates the coordinate of each coordinate points on the screen of pinhole imaging system model.

The embodiment of the invention also provides a kind of terminal device, comprises above-mentioned electronic chart demonstration device at least.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (13)

1. an electronic chart exhibiting method is characterized in that, comprising:

The height of electron gain map, width and three-dimensional perspective angle;

According to height, width and the three-dimensional perspective angle of electronic chart, be identified for the pinhole imaging system model of three-dimensional perspective projection process;

Use described pinhole imaging system model, described electronic chart is carried out the three-dimensional perspective projection process, obtain the perspective projection coordinate of described electronic chart;

Perspective projection coordinate according to described electronic chart represents described electronic chart.

2. the method for claim 1 is characterized in that, according to height, width and the three-dimensional perspective angle of electronic chart, is identified for the pinhole imaging system model of three-dimensional perspective projection process, specifically comprises:

The height of electronic chart is set to the height of pinhole imaging system model;

The width of electronic chart is set to the width of pinhole imaging system model;

According to height and the three-dimensional perspective angle of electronic chart, determine the length of pinhole imaging system model.

3. method as claimed in claim 2 is characterized in that, according to height and the three-dimensional perspective angle of electronic chart, determines the length of pinhole imaging system model, specifically comprises:

Obtain isosceles triangle, the drift angle angle of described isosceles triangle equals described three-dimensional perspective angle, and the waist length of described isosceles triangle equals the height of described electronic chart;

Obtain the intersection point of the base extended line of the vertical centering control separated time of waist of described isosceles triangle and described isosceles triangle;

According to the central point of the waist of described isosceles triangle and the distance between the described intersection point, obtain the length of pinhole imaging system model.

4. the method for claim 1 is characterized in that, uses described pinhole imaging system model, and described electronic chart is carried out the three-dimensional perspective projection process, obtains the perspective projection coordinate of described electronic chart, specifically comprises:

Determine the cross section of described electronic chart in the imaging awl of described pinhole imaging system model;

Calculate the coordinate of each coordinate points on the screen of pinhole imaging system model on the described cross section, the perspective projection coordinate that the described coordinate that calculates is described electronic chart.

5. method as claimed in claim 4 is characterized in that, calculates the coordinate of each coordinate points on the screen of pinhole imaging system model on the described cross section, specifically comprises:

Calculate the coordinate of each coordinate points on the imaging surface of correspondence on the described cross section;

According to the coordinate of each coordinate points on the imaging surface of correspondence, calculate the coordinate of each coordinate points on the screen of pinhole imaging system model.

6. method as claimed in claim 5 is characterized in that, coordinate points is the two-dimensional coordinate point;

Calculate the coordinate of coordinate points on the imaging surface of correspondence on the described cross section by following manner:

x′＝x

$y^{\′}=\frac{H\×[F-y\×\sin \left(a\right)]}{2F}-\frac{h}{2}+y\×\cos \left(a\right)$

Wherein, x, y are respectively horizontal stroke, the ordinate of coordinate points on electronic chart;

X ', y ' are respectively horizontal stroke, the ordinate of coordinate points in the imaging surface of correspondence;

H is the height of pinhole imaging system model;

2F is the length of pinhole imaging system model;

A is the three-dimensional perspective angle of electronic chart;

By the coordinate of following manner coordinate points on the screen of pinhole imaging system model:

${\mathrm{Xt}}^{\′}=x^{\′}\×\frac{F}{F-y\×\sin \left(a\right)}$

${\mathrm{Yt}}^{\′}=y^{\′}\×\frac{F}{F-y\×\sin \left(a\right)}$

Wherein, Xt ', Yt ' are respectively horizontal stroke, the ordinate of coordinate points on the screen of pinhole imaging system model.

7. method as claimed in claim 5 is characterized in that, coordinate points is three-dimensional coordinate point;

Calculate the coordinate of coordinate points on the imaging surface of correspondence on the described cross section by following manner:

x″＝x

$y^{\′\′}=\frac{F-y\×\sin \left(a\right)-z\×\cos \left(a\right)}{2F}\×H-z\×\sin \left(a\right)-\frac{H}{2}+y\×\cos \left(a\right)$

Wherein, x, y, z are respectively horizontal stroke, vertical, the ordinate of coordinate points on electronic chart;

X ", y " is respectively horizontal stroke, the ordinate of coordinate points in the imaging surface of correspondence;

H is the height of pinhole imaging system model;

2F is the length of pinhole imaging system model;

A is the three-dimensional perspective angle of electronic chart;

By the coordinate of following manner coordinate points on the screen of pinhole imaging system model:

${\mathrm{Xt}}^{\′\′}=x^{\′\′}\×\frac{F}{F-y\×\sin \left(a\right)-z\×\cos \left(a\right)}$

${\mathrm{Yt}}^{\′\′}=y^{\′\′}\×\frac{F}{F-y\×\sin \left(a\right)-z\×\cos \left(a\right)}$

Wherein, Xt ", Yt " is respectively horizontal stroke, the ordinate of coordinate points on the screen of pinhole imaging system model.

8. an electronic chart demonstration device is characterized in that, comprising:

Obtain the unit, be used for height, width and the three-dimensional perspective angle of electron gain map;

The model determining unit is used for height, width and three-dimensional perspective angle according to electronic chart, is identified for the pinhole imaging system model of three-dimensional perspective projection process;

Three-dimensional perspective projection process unit is used for using described pinhole imaging system model, and described electronic chart is carried out the three-dimensional perspective projection process, obtains the perspective projection coordinate of described electronic chart;

Electronic chart represents the unit, is used for the perspective projection coordinate according to described electronic chart, represents described electronic chart.

9. device as claimed in claim 8 is characterized in that, the model determining unit specifically comprises:

Subelement highly is set, and the height that is used for electronic chart is set to the height of pinhole imaging system model;

Width arranges subelement, and the width that is used for electronic chart is set to the width of pinhole imaging system model;

Length is determined subelement, is used for height and three-dimensional perspective angle according to electronic chart, determines the length of pinhole imaging system model.

10. device as claimed in claim 9 is characterized in that, length determines that subelement specifically comprises:

The triangle acquisition module is used for obtaining isosceles triangle, and the drift angle angle of described isosceles triangle equals described three-dimensional perspective angle, and the waist length of described isosceles triangle equals the height of described electronic chart;

The intersection point acquisition module is used for obtaining the intersection point of the base extended line of the vertical centering control separated time of waist of described isosceles triangle and described isosceles triangle;

The length acquisition module is used for obtaining the length of pinhole imaging system model according to the central point of the waist of described isosceles triangle and the distance between the described intersection point.

11. device as claimed in claim 8 is characterized in that, three-dimensional perspective projection process unit specifically comprises:

Subelement is determined in the cross section, is used for determining the cross section of described electronic chart in the imaging awl of described pinhole imaging system model;

The coordinate Calculation subelement is used for calculating the coordinate of each coordinate points on the screen of pinhole imaging system model on the described cross section, and the coordinate that obtains is the perspective projection coordinate of described electronic chart.

12. device as claimed in claim 11 is characterized in that, the coordinate Calculation subelement specifically comprises:

The first coordinate Calculation module is used for calculating the coordinate of each coordinate points on the imaging surface of correspondence on the described cross section;

The second coordinate Calculation module is used for according to the coordinate of each coordinate points on the imaging surface of correspondence, calculates the coordinate of each coordinate points on the screen of pinhole imaging system model.

13. a terminal device is characterized in that, comprises the described electronic chart demonstration device of claim 8～12.

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