After the fact, you may not be able to tell if a district map was gerrymandered. But you can sure as hell tell if gerrymandering was happening, simply by exami

After the fact, you may not be able to tell if a district map was gerrymandered. But you can sure as hell tell if gerrymandering was happening, simply by examining the process itself. Was the process transparent and dictated by clear and unambiguous guidelines? Was it based purely on population density statistics, or were sociodemographics taken into account? Were those executing the process a member of the political establishment or were they independent and arms length? Etc, etc. So you solve the problem by designing the process in such a way that it's resistant to partisan tampering. 'course, any attempt to do that will cause the majority to cry foul specifically because they benefit from gerrymandering...