[gdal-dev] stere

[Andre Joost]

Am 14.07.2017 um 19:06 schrieb Patrick L. Francis:
>
>> I work with NWS grids a lot for nexrad data. They are in a 1/40 lfm
>> grid. Your data looks like it might be an a 1/1 LFM grid. Here is the
>> WKT I would use for a 1/1 LFM grid. Each cell is 190.5 km.
>
> thank you for replying brian....  the output using those specs ended up
> looking like:
> http://www.blindleper.com/files/gdal/brian_mccormick_try.jpg
>
> from: +proj=stere +lat_0=90 +lat_ts=60 +lon_0=-105 +k=1 +x_0=0 +y_0=0
> +a=190500.0  +b=190500.0 +units=m +no_defs
>

a and b are the parameters for the ellipsoid, which seem totally wrong 
now. Brian suggested a scale factor, which would be +to_meter instead of 
+units=m.

If you run gdalsrsinfo on a text file with brian's WKT, it reports:

PROJ.4 : '+proj=stere +lat_0=90 +lat_ts=60 +lon_0=-105 +k=1 +x_0=2095500 
+y_0=7810500 +a=6371200 +b=6371200 +to_meter=190500 +no_defs '

HTH,
André Joost