This is a simple command-line tool for editing portals in dmaps. It outputs a list of portals from a dmap in the format index,x,y, and allows you to write them back to the dmap in the same format. It can be compiled for Windows, Linux, or Mac using the Golang compiler, and I have attached the Windows build of the tool. I wrote the tool in about an hour, so it's a bit messy, but all open source and MIT licensed for whoever wants to do something with it. Figured that I'd write it on the third request.