[FWTools] How to reproject gif image into geotiff

Frank Warmerdam warmerdam at pobox.com
Fri Nov 28 12:11:20 EST 2008


kennypollito1 at verizon.net wrote:
> Hi,
> 
> I am try to automate a map reproject  using OpenEV or FWTools. There are 
> two images: world background image from srtm30plus-world_pctshade 
> <javascript:PopUpWindow('../data/basemaps/srtm30plus/srtm30plus-world_pctshade.gif','BrowseGraphic','620','320','custom','front');> 
> and NWS GFS product image 
> http://www.nco.ncep.noaa.gov/pmb/nwpara/analysis/namer/gfs/00/images/gfs_ten_006s.gif
> 
> Can someone help me to understand how to reproject gfs_ten_006s.gif so 
> it will fit perfect to srtm30plus-world_pctshade.tif? For example, the 
> Geo tiff file srtm30plus-na_pctshade.tif fit perfect to 
> srtm30plus-world_pctshade.tif.
> 
> I am helping NWS to create new product that will help all of us to 
> better understand and view forecast image data.

Kenny,

Do you know anything about the coordinate system and extents of the
gfs_ten_006s file?  The srtm30plus products are *normally* geographic
(or we can think of it as equirectangular) so this is easily represented
if you have the whole world.  For instance you might produce a georeferecned
version using something like:

gdal_translate -of VRT -a_ullr -180 90 180 90 -a_srs WGS84 \
    srtm30plus-world_pctshade.gif srtm30plus-world_pctshade-geo.vrt

If you can establish bounds and a coordinate system for your gfs_ten_006s
product, then you can gdalwarp one onto the other.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent



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