3

I am trying to adjust a vector polygon dataset using ogr2ogr spline transformation with cmd commands like:

C:\\OSGeo4W64\\bin\\ogr2ogr.exe -f "ESRI Shapefile" C:\\path\\output.shp -order 3 -tps -gcp -13163.1627 271026.6107 -13274.2879 271201.236 -gcp 64464.2679538 -210398.439419 64390.5172491 -210240.678326 -gcp 98432.5310433 -181184.99898 98313.298804 -180985.232826 C:\\path\\input.shp

Also I try to do this inside Python:

import os
control_points = (
"-gcp -13163.1627 271026.6107 -13274.2879 271201.236 "
"-gcp -12706.1672 271461.5611 -12843.4862 271599.4093 "
"-gcp 98432.5310433 -181184.99898 98313.298804 -180985.232826 "
"-gcp 64464.2679538 -210398.439419 64390.5172491 -210240.678326 "
)
command = 'C:\\OSGeo4W64\\bin\\ogr2ogr.exe -f "ESRI Shapefile" C:\\path\\output.shp -order 3 -tps ' + control_points + 'C:\\path\\input.shp'
print command
os.system(command)

With a few points like this it works fine. But actually I have much more control points, more than 1000. I need to use them all because the dataset covers the entire country. And when I write into the command all my GCPs, the Python script doesn't produce any output at all (no errors), and when I paste this command into the Command prompt it just cuts my command and then gives an error from ogr2ogr.

I found out that the maximum number of characters in the command prompt is 8191 but my command has 79792 characters.

So, how can I use ogr2ogr with hundreds of control points? Is there a way to store them in some batch file or variable? The GDAL page only says that -gcp option may be provided multiple times to provide a set of GCPs, directly in the command.

7

This page, which lists general command-line options, says there's an "--optfile" argument:

Read the named file and substitute the contents into the command line options list. Lines beginning with # will be ignored. Multi-word arguments may be kept together with double quotes.

Putting your GCPs arguments in a text file might let you work around the command-line length limitation.

  • 1
    Thank you for the tip, it works with control_points = "--optfile C:\\path\\gcp.txt " But I don't understand their words about double quotes, because inside the gcp.txt I had to write just -gcp -13163.1627 271026.6107 -13274.2879 271201.236 -gcp -12706.1672 271461.5611 -12843.4862 271599.4093 without quotes, because with quotes it was not working. – nadya May 17 '17 at 14:25
  • 1
    Glad to hear it works! Do you have an example of how you were including the quotes? I would assume that they would work in the same was as on the command line, where ogr2ogr -gcp "-12706.1672 271461.5611 -12843.4862 271599.4093" would cause "ogr2ogr" to be argv[0], "-gcp" to be argv[1], and "-12706.1672 271461.5611 -12843.4862 271599.4093" to be argv[2]. – mikewatt May 17 '17 at 18:05
  • I tried to quote every line "-gcp -13163.1627 271026.6107 -13274.2879 271201.236 " "-gcp -12706.1672 271461.5611 -12843.4862 271599.4093 " like it was in my Python variable. Your example with quoting only coordinates is also not working. Only without any quotes it works. – nadya May 18 '17 at 10:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.