I have many raster (bitmap) images that I'd like to transform from unprojected lat-lon to a projected rendering. (e.g. GIF, PNG).
I don't understand how to use PROJ.4 to render the resulting image. I'd like a library or software that can do this all automatically. GRASS GIS is large. The transforms are relatively simple transforms and of raster images only.
Or is there basic code or an example of how I would do this? using PROJ.4 and GraphicsMagick.
It is a little confusing about what you are asking for here.
If you are trying to convert from a LAT Long geo referenced image to another projection or if you just want to keep the current geo referencing of a bitmap and convert it to another format such as GIF or PNG.
If you wish to change formats I don't believe PNG or GIF supports geo referencing in its header so this will not be possible. If you are looking at trying to compress the image so it doesn't take up as much space you could look at JPEG or JPEG2000 as these support both. For a full list of image formats and what supports geo referencing and what does not this page is a good place to start: Link
If you wish to change the co-ordinate projection from lat, long to something else (like Mercator mga zone XX) You can use something like GDAL to batch the process.
Download from here: http://trac.osgeo.org/gdal/wiki/DownloadingGdalBinaries
See here for a list of inlcuded utilities: Link
See here for the utility help for changing projections: Link
See here for utility that changes image formats: Link
Hopefully that will be of help to you.
