[gdal-dev] help with gdalwarp

Alex Bernstein pofig37 at gmail.com
Sun Jan 4 18:25:17 EST 2009


Joaquim,

Thanks for trying to help. I'm actually just interested in the map of
Africa from this global map. May be I'll try to figure out gdal
commands to crop and transform just the relevant region.

--Alex

On Mon, Jan 5, 2009 at 1:05 AM, Joaquim Luis <jluis at ualg.pt> wrote:
> Alex Bernstein wrote:
>>
>> On Sun, Jan 4, 2009 at 11:00 PM, Joaquim Luis <jluis at ualg.pt> wrote:
>
>> Joaquim, renaming the world file to NE2_land_only.jgw was one of first
>> things I've done, sorry I forgot to mention that. So it's not reason
>> for the problems I'm having with reprojection.
>>
>> The coordinates in world file are specified in degrees, is this how it
>> supposed to be, or do I need to pass any switches to gdalwarp to
>> indicate that?
>
> Alex,
>
> Sorry, I don't know. Normally "Lambert Azimuthal Equal Area" should take two
> standard parallels, but it makes no difference here. I tried
>
> gdalwarp -s_srs "+proj=eqc +lat_ts=0 +lon_0=0 +datum=WGS84"
> -t_srs "+proj=laea +lat_1=20n +lat_2=60n" -co TFW=YES NE2_land_only.jpg
> NE2_land_only_laea.tif
>
> which reports
> ...
> Upper Left  (-180.0111111,  89.4085425) (  0d 0'5.82"W,  0d 0'2.91"N)
> Lower Left  (-180.0111111, -89.3968263) (  0d 0'5.82"W,  0d 0'2.91"S)
> Upper Right ( 179.9964220,  89.4085425) (  0d 0'5.82"E,  0d 0'2.91"N)
> Lower Right ( 179.9964220, -89.3968263) (  0d 0'5.82"E,  0d 0'2.91"S)
> Center      (  -0.0073446,   0.0058581) (  0d 0'0.00"W,  0d 0'0.00"N)
>
> but the file is not reprojected either.
>
> I don't know if it is related but I found many instances where gdalwarp
> fails
> on global files. I reported that twice, last one on ticket
> http://trac.osgeo.org/gdal/ticket/2305
> but unfortunately it didn't deserve any attention.
>
>


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