This macro will identify contiguous sets of polygons. It marks each polygon with the lowest ID number from among the contiguous group of polygons to which it belongs. The polygons can then be merged into districts using the "Merge By Value" function in the Maptitude GUI.
Free and open source (GPLv3 license).
Contributing columnist Catherine Burton interviewed Michael Carson, GIS manager at the City of Burbankwhere, as in many cities, GIS work continues to be a critical element in city administration and planning.