[gdal-dev] Discrepancy in proj values between ubuntu-small and ubuntu-full images

[Rajsekar Manokaran]

Hi gdal devs and users,

I came across a discrepancy in proj. values between ubuntu-small and
ubuntu-full docker images even for the same gdal version tag.  I tried to
convert a few coords from epsg:4326 to epsg:2271.  The coords are:

Input:
-77.75 40.16666666666666  # this is the center meridian, lat of 2271
-75.18094433657971 40.25904959199275  # another sample point

The outputs of all ubuntu-small-* images seem to be correct, but the
ubuntu-full-* images have about 1 feet error (2271 uses US_SURVEY_FEET
units).

Here's how I run it:

$ docker run --rm -i osgeo/gdal:"$tag" cs2cs '+init=epsg:4326' '+to'
'+init=epsg:2271' < input
where tag is the docker tag: "ubuntu-full-3.2.2", or "ubuntu-small-3.4.1",
etc.

Here are the outputs for the ubuntu-full images:

output-ubuntu-full-3.2.2
1968499.39      -0.15 0.00
2685535.97      44295.90 0.00
output-ubuntu-full-3.3.3
1968499.39      -0.15 0.00
2685535.97      44295.90 0.00
output-ubuntu-full-3.4.1
1968499.39      -0.15 0.00
2685535.97      44295.90 0.00

Here are the outputs for the small images:

output-ubuntu-small-3.2.2
1968500.00      -0.00 0.00
2685536.18      44296.27 0.00
output-ubuntu-small-3.3.3
1968500.00      -0.00 0.00
2685536.18      44296.27 0.00
output-ubuntu-small-3.4.1
1968500.00      -0.00 0.00
2685536.18      44296.27 0.00

The first input is the center and so should translate to "(false east,
false north)".  Going by that, the small versions seem to be more correct.
Any idea why this difference in the values?

-
Rajsekar
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