I am a vectors guy mostly, but for a current project I need to work with a bunch of old scanned paper maps (ww2 bomb damage maps for London, if your interested!)
We scanned and georeferenced the maps, and now want to create a tiled composite layer for serving on a website. We will cut out the borders obviously, thats not the issue here.
Problem is, that there are unsightly visual colour and brightness differences between map sheets. I am a bit at a loss as to how to equalise them so to give a coherent visual look. I read up on histogram equalising, but my current toolbox (Manifold GIS, GDAL, GeoServer) doesnt seem to have the required functionality.
Example of 4 scans already georeferenced: