[gdal-dev] Best way to add geo-referencing to a PNG

[Christopher Barker]

Hi folks,

I have a set of PNGs that I would like to add geo-referencing to. 
Frankly, I'm not sure what projection they are in, but I do know the 
bounding box in lat-long, and I think they are simple geo-coordinates.

I tried adding a *.pgw "world file", that looks like this:

0.04430379
0.0
0.0
-0.03201024
-85.0
45.0

That seems to get the basics: QGIS puts it in the right place on the 
map, and gdal_translate seems to be able to make a geotiff out of it. 
However, I'd like to be able to put a bit more information in, like that 
it's wgs84, and geo-coordinates. How can I do that? It seems an 
*.aux.xml file should be able to do what I want. but I don't what to put 
in that.

Has anyone got a sample that I could follow?

Or is there another way?

-Chris





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Christopher Barker, Ph.D.
Oceanographer

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