[gdal-dev] gdalwarp results differ in different gdal versions?

[Meghan Burris]

That is correct, my image is a Mars southern pole image. Those radii are
pulled from another file but I have run the command with the +a/b being in
meters, specifically 3396000 and I still get the same result (missing polar
information).

I have also run the command using -wo SAMPLE_GRID=YES and nothing changed.
I just tried the command with the -wo SAMPLE_GRID and the +a/b being 337500
and I still get the pole clipped.

I would be happy to submit a ticket. Is this the location that I would do
that :  https://github.com/OSGeo/gdal

Thank you Trent and Even!


On Fri, May 8, 2020 at 11:55 AM Even Rouault <even.rouault at spatialys.com>
wrote:

> Meghan,
>
>
>
> Handling poles tend to be fragile, so perhaps something that worked
> previously no longer works.
>
> Did you try -wo SAMPLE_GRID=YES ?
>
>
>
> If that still doesn't work, the best is you open a ticket with an input
> image attached (dimensions reduced as much as possible while still
> reproducing the issue), and the exact command line to reproduce.
>
> I'd note that in your below attempt there's a likely mismatch in the units
> of the target ellipsoid w.r.t the initial one. This should be a/b=3375000.
>
>
>
> Even
>
>
>
> > Hello!
>
> >
>
> > I'm hoping someone can shine some light in my direction because I can't
>
> > find any answers.
>
> >
>
> > I'm trying to warp a Polar Stereographic image into an Equal Cylindrical
>
> > projection. When I run the gdalwarp command on older versions
> (specifically
>
> > 1.8.1), my image looks as I would expect. When I run the same command in
>
> > gdal versions 2.2.4 or 2.4.1, the pole is clipped out and missing. I've
>
> > tried adding different parameters such as -te, and multiple -wo
> parameters
>
> > and nothing works for me. Am I missing something? Any help would be
> greatly
>
> > appreciated because I can't use the older versions anymore in my script.
> My
>
> > original warp command is below as well as the original polar header.
>
> > Although, I have tried multiple images and I still don't get the results
>
> > that I was getting in version 1.8.
>
> >
>
> > Thank you in advance!!
>
> >
>
> > Meghan
>
> >
>
> > gdalwarp -overwrite -of GTiff -t_srs "+proj=eqc +a=3375.0 +b=3375.0
>
> > +towgs=0,0,0,0,0,0" input.tif output.tif
>
> >
>
> > Driver: GTiff/GeoTIFF
>
> > Files: SP_MY34_summer_18mpp_gd2.tif
>
> > Size is 35928, 35815
>
> > Coordinate System is:
>
> > PROJCS["unnamed",
>
> > GEOGCS["unnamed ellipse",
>
> > DATUM["unknown",
>
> > SPHEROID["unnamed",3396000,0]],
>
> > PRIMEM["Greenwich",0],
>
> > UNIT["degree",0.0174532925199433]],
>
> > PROJECTION["Polar_Stereographic"],
>
> > PARAMETER["latitude_of_origin",-90],
>
> > PARAMETER["central_meridian",0],
>
> > PARAMETER["scale_factor",1],
>
> > PARAMETER["false_easting",0],
>
> > PARAMETER["false_northing",0],
>
> > UNIT["metre",1,
>
> > AUTHORITY["EPSG","9001"]]]
>
> > Origin = (-383491.061348880291916,410399.872797137824818)
>
> > Pixel Size = (17.999204982112094,-17.999204982112094)
>
> > Metadata:
>
> > AREA_OR_POINT=Area
>
> > Image Structure Metadata:
>
> > COMPRESSION=DEFLATE
>
> > INTERLEAVE=BAND
>
> > Corner Coordinates:
>
> > Upper Left ( -383491.061, 410399.873) ( 43d 3'31.36"W, 80d32'41.89"S)
>
> > Lower Left ( -383491.061, -234241.654) (121d25' 1.79"W, 82d25'46.00"S)
>
> > Upper Right ( 263184.375, 410399.873) ( 32d40'17.59"E, 81d47'18.78"S)
>
> > Lower Right ( 263184.375, -234241.654) (131d40'12.00"E, 84d 3'39.60"S)
>
> > Center ( -60153.343, 88079.110) ( 34d19'51.59"W, 88d12' 2.26"S)
>
> > Band 1 Block=256x256 Type=Byte, ColorInterp=Gray
>
> > Min=2146.000 Max=10112.000
>
> > Minimum=2146.000, Maximum=10112.000, Mean=5382.365, StdDev=1638.523
>
> > NoData Value=0
>
> > Overviews: 17964x17908, 8982x8954, 4491x4477, 2246x2239, 1123x1120,
>
> > 562x560, 281x280, 141x140, 71x70
>
> > Metadata:
>
> > STATISTICS_MAXIMUM=10112
>
> > STATISTICS_MEAN=5382.3651107267
>
> > STATISTICS_MINIMUM=2146
>
> > STATISTICS_STDDEV=1638.5226548658
>
>
>
>
>
> --
>
> Spatialys - Geospatial professional services
>
> http://www.spatialys.com
>
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