[gdal-dev] Re: EASE-grid projection

[Markus Neteler]

Dan, Jose,

On Fri, Oct 10, 2008 at 8:09 PM, Dan Stahlke <dan at gina.alaska.edu> wrote:
> Jose,
>
> The north pole version works for me, perhaps because of the '+init=' part:
> (although that probably shouldn't matter...)
>   gdalwarp -t_srs '+init=epsg:3408' ...

I wonder if this resolves
http://trac.osgeo.org/gdal/ticket/2584

where I obtained a flipped earth... (seen from North pole).

Thanks
Markus

> Maybe the equatorial version of EASE is different.
>
> If you are giving the full proj4 definition "+proj=cea ..." you might try
> adding "+no_defs" at the end.  Otherwise, you usually end up getting some
> sort of default flatting value or something that tends to interfere whenever
> an explicit radius is specified.  Probably the "+ellps=sphere" ends up
> overriding the faulty default value.
>
> - Dan
>
> Jose Gomez-Dans wrote:
>>
>> Hi,
>> I know it's unpolite to reply to self, but I think I might have cracked
>> this one. Comments welcomed...
>>
>>
>> 2008/10/10 Jose Gomez-Dans <jgomezdans at gmail.com
>> <mailto:jgomezdans at gmail.com>>
>>
>>
>>    $ gdalwarp --debug on -of GTiff -s_srs "+proj=cea +lat_0=0
>>    +lon_0=0 +lat_ts=30 +a=6371228.0 +units=m" -t_srs 'EPSG:4326'
>>    INPUT OUTPUT.tif
>>    OGR_PROJ4: Can't find ellipse definition in:
>>    +proj=cea +lat_0=0 +lon_0=0 +lat_ts=30 +a=6371228.0 +units=m
>>    ERROR 1: Translating source or target SRS failed:
>>    +proj=cea +lat_0=0 +lon_0=0 +lat_ts=30 +a=6371228.0 +units=m
>>
>>
>> If I add the +ellps=sphere (hint is here:
>>  <http://nsidc.org/data/ease/ease_grid.html#whySpherical>. What's wrong with
>> having a flat Earth!!! :D), I am able to reproject the data.
>>
>> Is this a sound approach?
>>
>> Thanks,
>> Jose
>>
>>
>> --
>> Centre for Terrestrial Carbon Dynamics
>> Department of Geography, University College London
>> Gower Street, London WC1E 6BT, UK
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>



-- 
Open Source Geospatial Foundation
http://www.osgeo.org/
http://www.grassbook.org/