Programmatically georeference raster from other raster

Discussion created by zhliu on Jul 4, 2011
Latest reply on Jul 17, 2012 by martinscheiber
I have the following task:

I have a georeferenced (Geo-)Tiff file, a.tif. Using an external program, I create another plain (no georeferencing data) TIFF file b.tif. (Imagine say that I open a.tif in Photoshop, apply a motion blur to the whole image, and save the result as b.tif, but in such a way that the georeferencing metadata is lost.)

Now, b.tif and a.tif represent the same region on the globe using exactly the same projection. a.tif carries information about where this region is, but b.tif does not; I want to copy that information from a.tif to b.tif. Or in other words, I want to alter b.tif so that it is perfectly aligned on top of a.tif if I open them both in ArcMap. I need to do this from a Python script.

a.tif and b.tif will have the same width and height (in pixels), but not necessarily the same color depth.

This seems like it should be a simple task with ArcGIS scripting, but I can't figure out how to do this. I think I can copy the projection data by using DefineProjection_management(), but as far as I can tell, this only changes the projection and not the actual position of the image within the projection's coordinate system.

I am using version 10 of ArcGIS.

Any help would be much appreciated.