[gdal-dev] RFC 32 - gdallocationinfo utility
EAdam at co.lincoln.or.us
Mon Nov 1 13:26:09 EDT 2010
This is a helpful new utility.
I read the documentation and tried it out. Using gdallocationinfo to find the elevation at a given lat/long location seems like a reasonable use. It may be desirable to input and output an ogr layer rather than a single point. For instance, what are the elevations at these points in this shapefile?
I tried to approach that problem by putting the coordinates into a file with ogrinfo and then use that file as an --optfile for the x y. That didn't work the way that I tried it. Can an --optfile be used for the x y input?
ogrinfo town.shp town | grep 'POINT' | sed 's/ POINT (//' | sed 's/)//' > xyinput2.txt
gdallocationinfo -s_srs "EPSG:2913" townraster.tif --optfile xyinput2.txt
Usage: gdallocationinfo [--help-general] [-xml] [-lifonly] [-valonly]
[-b band]* [-s_srs srs_def] [-geoloc] [-wgs84]
srcfile x y
What would be the proper approach to the above hypothetical problem? Is there an effective way to have an ogr input for gdallocaitoninfo? Perhaps -input_file_list my_liste.txt for the x y similar to gdalbuildvrt?
It looks like -s_srs applies to the x y input. -s_srs sometimes, i.e. gdalwarp, applies to the srcfile.
Is -wgs84 equivalent to -s_srs "EPSG:4326"?
These were my initial thoughts I hope that some of them may be helpful.
Thanks for the new utility, Eli
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