Raster layer - Howto?

[Gregor Mosheh]

Pascal Ehlert wrote:
> I'd like to use one of the new NASA Blue Marble Images (which are 
> available in TIFF format) for the
> background of my map.

Is that TIFF georeferenced (a geotiff?), or else do you have a worldfile 
for it? If not, then that data is just floating in nowhereville, well 
outside of your browser's view. :)

If I recall, the Blue Marble stuff is not a geotiff (use gdalinfo on it 
to see if it has a projection and a center and all) and you'll have to 
create your own world file. It's a simple text file that describes the 
pixel coordinates in order for the data to have a spatial location.

Don't worry, though: just punch "world file format" into Google and 
you'll be on your way in a few minutes. If not, ask back. :)

-- 
Gregor Mosheh / Greg Allensworth
System Administrator, HostGIS cartographic development & hosting services
http://www.HostGIS.com/

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