No, topology often focuses on things that are invariant under such things as corners, distances, and convexity, which can make it an extremely useful tool in a field awash in such concerns.
While many would classify the GP's library as one primarily concerned with computational geometry (but certainly not topography), there are large overlaps of computational geometry with computational topology. Many topology results won't be useful in an applied field like GIS, but other results will be extremely useful as they work regardless of the mess of real world measurements.
Classification of branches of mathematics is a losing game, anyway. You try to separate two bodies of work, you'll invariably find someone's extensive results that straddle the boundary.
While many would classify the GP's library as one primarily concerned with computational geometry (but certainly not topography), there are large overlaps of computational geometry with computational topology. Many topology results won't be useful in an applied field like GIS, but other results will be extremely useful as they work regardless of the mess of real world measurements.
Classification of branches of mathematics is a losing game, anyway. You try to separate two bodies of work, you'll invariably find someone's extensive results that straddle the boundary.