[gdal-dev] GOES-16 Projection Issue

[Even Rouault]

On mercredi 4 avril 2018 11:13:29 CEST Simon Proud wrote:
> Hello,
> I am trying to visualise GOES-16 data, but the output projection from
> gdal_translate appears faulty.
> This is the command I use:
> gdal_translate -a_srs "+proj=geos +a=6378137. +units=m +no_defs
> +b=6356752.31414 +x_0=0.0 +y_0=0.0 +ellps=GRS80 +lon_0=-75.0
> +f=.00335281068119356027 +h=35786023. +sweep=x" -a_ullr $ulx $uly $lrx
> $lry [input_file] [output_file]
> 

Simon,

This has been discussed recently on the list. Basically the issue is that GeoTIFF encoding has
no way to represent this projection properly.

Long version at
http://geotiff.maptools.narkive.com/3CqwNeMd/geos-projection-sweep-parameter

A potential workaround is to have a .tif + .tif.aux.xml file and forcing a baseline TIFF to be produced

In GDAL master, I've just committed a fix so that

gdal_translate input.tif output.tif -co PROFILE=BASELINE -a_srs "+proj=geos +a=6378137. +units=m +no_defs +b=6356752.31414 +x_0=0.0 +y_0=0.0 +ellps=GRS80 +lon_0=-75.0  +f=.00335281068119356027 +h=35786023. +sweep=x" 

works

With currently released versions, you have to do a more convoluted approach

1) Create a baslilne TIFF file
gdal_translate input.tif output.tif -co PROFILE=BASELINE

2) Create a dummy png file (1x1) with the projection info in .aux.xml
gdal_translate -of PNG test.tif output.png -a_srs "+proj=geos +a=6378137. +units=m +no_defs +b=6356752.31414 +x_0=0.0 +y_0=0.0 +ellps=GRS80 +lon_0=-75.0  +f=.00335281068119356027 +h=35786023. +sweep=x" -srcwin 0 0 1 1

3) Rename output.png.aux.xml to output.tif.aux.xml

4) Check with "gdalinfo output.tif" that you get the right projection info

Even

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