GCP File Formats
GCP File Formats
The RPC Orthorectification workflow reads GCP shapefiles, as well as ASCII GCP files with .pts extensions. Examples of .pts files are outlined below.
Regardless of the header format, all headers must include a projection info string for the RPC Orthorectification workflow to read them. GCP files can be in any map projection, but the RPC Refinement panel will always display map coordinates in a Geographic WGS-84 projection.
In contrast to shapefiles, .pts files refer to the upper-left corner of the first image pixel as (1,1). If your image is a spatial subset that contains XSTART and YSTART offset values from the original image, the .pts file image coordinates include this offset. The RPC Orthorectification workflow always refers to the upper-left pixel as (0,0). Thus, it will subtract (1,1) from GCP image coordinates from a full image, and it will subtract the XSTART and YSTART values from the image coordinates of a subsetted image.
Following are some examples of different .pts files that the RPC Orthorectification workflow will read. The bold headings refer to the specific tools that generate the .pts files.
Rigorous Orthorectification
0 -105.358423 39.953100 2226.000000 4690.000000 3918.000000
2 -105.152796 39.910608 1757.000000 5565.000000 5813.000000
RPC Orthorectification Tool
-105.42543081 40.08088580 2000.000000 2372.000000 4134.000000
-105.37496362 40.12966926 1000.000000 4128.000000 1910.000000
Build RPCs Tool
-105.48775571 40.16771721 2000.000000 201.000000 200.000000
Exterior Orientation Points File
6.96035926 45.86210997 4001.000000 4269.000000 5237.000000
6.88871043 45.87880951 3842.000000 3686.000000 5165.000000
Stereo GCP File Created from the DEM Extraction Module
Note: The RPC Orthorectification workflow reads the first two values, ignores the next two values, and reads the last three values.
5649.0000 7311.0000 6308.0000 8071.0000 -1.17410984e+002 4.77035482e+001 628.363000
Image-to-Map Registration
Note: This type of file does not contain any height information, so the default elevation is set to 0 meters.
5711285.2999 2114581.3280 1.000000 1.000000000000