CN105279341A - Method for intercepting google earth image and directly applying in engineering design - Google Patents

Abstract

The invention discloses a method for intercepting a google earth image and directly applying in engineering design. The method is characterized by comprising the following steps of 1), setting a coordinate system; 2), setting an image intercepting parameter; 3) intercepting the image and acquiring an image coordinate and a plane coordinate at a corner point; 4) performing biquadratic polynomial geometric correction and least square precision determination on homonymy points of the image according to a coordinate file; 5) performing re-sampling on an original image which satisfies a precision requirement according to a correction result according to a nearest neighbor interpolation method; and 6), automatically introducing a generated image into AutoCAD according to a geographic information tfw file for engineering design by designing personnel. The method provided by the invention has beneficial effects of conveniently and quickly intercepting the google earth image on condition that no topographical map exists or the verisimilitude of the topographical map is relatively low, realizing no requirement for fieldwork measurement in manufacturing a high-precision orthoimage, and facilitating early-period smooth design operation of engineering design personnel.

Description

A kind ofly intercept the method that Google Earth image directly applies to engineering design

Technical field

The present invention relates to and a kind ofly intercept the method that Google Earth image directly applies to engineering design, belong to engineering design technology field.

Background technology

The preliminary stage such as can to grind in engineering designs such as electric power, railway and highways, project planner usually relies on the topomap of 1:10000 equal-scale and carries out engineering design.In recent years, Google Earth is widely used in project design industry because image resolution is high, Up-to-date state strong, project planner needs by software intercepts image, is inserted in AutoCAD and carries out Computer Aided Design work in the image intercepted after selecting the clearly demarcated photo control point of some features to carry out geometric correction by field operation GPS field survey after generating the orthography with GEONET ruling.Although this working method precision can meet the demands, inefficiency needs to use various software could complete design work.At present, in some economically developed regions, the plane precision of Google Earth can reach the requirement of 1:10000 topomap substantially, if can carry out computer software secondary development by efficiency utilization this part image api function of making full use of Google Earth and providing in engineering design early stage, can be applied to engineering design fast.

At present, a kind of method is not also had directly to become the flat image under local engineering coordinate system to be successfully applied to engineering design the sphere video conversion of Google Earth.

Summary of the invention

For solving the deficiencies in the prior art, the object of the present invention is to provide a kind of intercepting Google Earth image method, without topomap and the situation not needing field operation measurement correction, directly applying to engineering design.

In order to realize above-mentioned target, the present invention adopts following technical scheme:

Intercept the method that Google Earth image directly applies to engineering design, it is characterized in that, comprise the following steps:

Step 1) coordinate system arranges: engineering respective coordinates system is set, comprises ellipsoid corresponding to engineering, projective parameter is arranged and Google Earth adopts coordinate system and the conversion parameter of engineering coordinate system and input;

Step 2) setting of image intercepting parameter: the scope of intercepting image, height and time delay being set, needing to intercept the quantity of image according to intercepting high computational transverse and longitudinal;

Step 3) intercept image obtain corner point image coordinate and planimetric coordinates: the api function provided according to Google Earth obtains image upper left, upper right, bottom right, the pixel coordinate of 4, lower-left angle point and center and latitude and longitude coordinates, origin coordinate system transform parameter according to arranging converts latitude and longitude coordinates to planimetric coordinates, forms coordinate file;

Step 4) according to coordinate file, quadratic polynomial geometric correction and least square accuracy assessment are carried out to image same place;

Step 5) to the image meeting accuracy requirement, adopt the method for arest neighbors interpolation to carry out resampling according to correcting result to raw video;

Step 6) generate the GeoTiff orthography being with geography information file tfw, be automatically imported AutoCAD according to geography information tfw file and carry out engineering design for designer.

Aforesaidly a kind ofly intercept the method that Google Earth image directly applies to engineering design, it is characterized in that, described step 2) in arrange intercept image scope in the following ways:

(1) in Google Earth, select image capturing range, the line route that image capturing range comprises rectangular extent or arranges bandwidth or the planar figure drawn arbitrarily;

(2) in AutoCAD, draw the wire of arbitrary shape, planar figure.

The beneficial effect that the present invention reaches: without topomap or the poor situation of topomap Up-to-date state, the Google Earth image that can intercept easily and fast, measure without the need to field operation and be namely made into the harmless orthography of precision, facilitate project planner to carry out design effort smoothly in early stage.

Accompanying drawing explanation

Fig. 1 is schematic flow sheet of the present invention;

Fig. 2 is that coordinate system arranges interface;

Fig. 3 is the main interface of image sectional drawing;

Fig. 4 intercepts the plane of video generation and the correction coordinate file of pixel coordinate;

Fig. 5 is that image geometry is corrected and accuracy assessment file;

Fig. 6 is the content of the geography information file tfw generated;

Fig. 7 is existing topomap in Engineering Zone;

Fig. 8 is automatically imported GeoTiff to AutoCAD and existing topomap Overlay figure.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.Following examples only for technical scheme of the present invention is clearly described, and can not limit the scope of the invention with this.

As shown in Figure 1, a kind ofly intercept the method that Google Earth image directly applies to engineering design, comprise the following steps:

Step 1), setting engineering coordinate system: the ellipsoid that input engineering is corresponding, input projective parameter comprises central meridian, supposes eastern coordinate, supposition north coordinate, and the Bursa model parameter of the WGS84 that input Google Earth is corresponding and engineering respective coordinates system comprises translational movement DX, DY, DZ and rotation amount RX, RY, RZ and scale ratio K.

Arrange the coordinate system parameter that engineering is corresponding as shown in Figure 2, comprise corresponding ellipsoid, center latitude, suppose eastern coordinate, supposition north coordinate, the WGS84 coordinate that Google Earth is corresponding is tied to Bursa model 7 parameter of local coordinate system corresponding to engineering.

Step 2), image display optimum configurations: the scope choosing the image of required Engineering Zone, should arrange the width in path to banded landform engineering; Arrange and intercept viewpoint height corresponding to image; Time delay, according to the viewpoint height of correspondence, the size of computer screen with intercept range computation one and shield the length and width of image, calculate the capable and longitudinal m row screen image of horizontal n, thus calculate the size of whole image.

Arrange the parameter that corresponding intercepting Google Earth image needs as shown in Figure 3, input sectional drawing height, the situation that there is not dislocation for guarantee sectional drawing should set certain time delay, carries out sectional drawing by choosing rectangle diagonal two-point locating.

Step 3), the api function adopting Google Earth to provide and WindowsAPIHOOK technology, by the Google Earth image under the current computer screen of screen copy, and calculate the 1st row the 1st row image upper left corner, the 1st row m row image upper right corner, n-th line the 1st row lower left corner, the n-th line m row image lower right corner, the n-th/2 row, the pixel coordinate that m/2 row image center is corresponding.The GetPointOnTerrainFromScreenCoords function in Google Earth is utilized to adopt the latitude and longitude coordinates of record the 1st row the 1st row image upper left corner, the 1st row m row image upper right corner, n-th line the 1st row lower left corner, the n-th line m row image lower right corner, the n-th/2 row m/2 row image center.Automatically planimetric coordinates is converted to by coordinate conversion while obtaining the longitude and latitude of above-mentioned point.Form correction coordinate file as shown in Figure 4.

Step 4), as shown in Figure 5 according to correction file adopt polynomial correction geometric correction is carried out to image, according to least square method calculate each corresponding image points root-mean-square error, carry out accuracy assessment.

Step 5), according to correction result to image, the sampling interval in setting X, Y-direction is with the method resampling of arest neighbors interpolation.

Step 6), according to the result of polynomial correction and resampling, the planimetric coordinates in the sampling interval of X, Y-direction, the image upper left corner is written in tfw file respectively, and generates GeoTiff image.

As shown in Figure 6, tfw file comprises following 6 row information:

(1) the pixel X resolution-scale in the X direction in map unit; (2) amount of tension; (3) revolve

Turn amount (angle); (4) the negative value of the pixel Y resolution-scale in the Y direction in map unit;

(5) the X ground coordinate of pixel coordinate (1,1); (6) the Y ground coordinate of pixel coordinate (1,1).

Wherein (1), (4) are step 5) resampling setting sampling interval, (2), (3) value is 0, (5), (6) can according to step 5) polynomial correction function obtains pixel coordinate (1,1) corresponding geographic coordinate X, Y.

By AutoCADObjectARX secondary exploitation technology, after reading tfw file and image width height, realize Geotiff image and be directly inserted in AutoCAD, complete the conversion from Google Earth image to AutoCAD flat image.

System is according to the width of tfw file, GeoTiff image and highly automatedly import in AutoCAD, be illustrated in figure 7 and utilize existing topomap to verify the plane precision of GeoTiff image, Figure 8 shows that the GeoTiff of generation and existing topomap superpose the effect of rear partial enlargement in AutoCAD, to verify whether the plane precision of GeoTiff image can meet the requirement of engineering design in early stage.

Effect of the present invention is, without topomap or the poor situation of topomap Up-to-date state, the Google Earth image that can intercept easily and fast, measures without the need to field operation and is namely made into the harmless orthography of precision, facilitate project planner to carry out design effort smoothly in early stage.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the technology of the present invention principle; can also make some improvement and distortion, these improve and distortion also should be considered as protection scope of the present invention.

Claims (2)

1. intercept the method that Google Earth image directly applies to engineering design, it is characterized in that, comprise the following steps:

Step 1) coordinate system arranges: engineering respective coordinates system is set, comprises ellipsoid corresponding to engineering, projective parameter is arranged and Google Earth adopts coordinate system and the conversion parameter of engineering coordinate system and input;

Step 2) setting of image intercepting parameter: the scope of intercepting image, height and time delay being set, needing to intercept the quantity of image according to intercepting high computational transverse and longitudinal;

Step 3) intercept image obtain corner point image coordinate and planimetric coordinates: the api function provided according to Google Earth obtains image upper left, upper right, bottom right, the pixel coordinate of 4, lower-left angle point and center and latitude and longitude coordinates, origin coordinate system transform parameter according to arranging converts latitude and longitude coordinates to planimetric coordinates, forms coordinate file;

Step 4) according to coordinate file, quadratic polynomial geometric correction and least square accuracy assessment are carried out to image same place;

Step 5) to the image meeting accuracy requirement, adopt the method for arest neighbors interpolation to carry out resampling according to correcting result to raw video;

Step 6) generate the GeoTiff orthography being with geography information file tfw, be automatically imported AutoCAD according to geography information tfw file and carry out engineering design for designer.

2. according to claim 1ly a kind ofly intercept the method that Google Earth image directly applies to engineering design, it is characterized in that, described step 2) in arrange intercept image scope in the following ways:

(1) in Google Earth, select image capturing range, the line route that image capturing range comprises rectangular extent or arranges bandwidth or the planar figure drawn arbitrarily;

(2) in AutoCAD, draw the wire of arbitrary shape, planar figure.