Thanks for the comprehensive answer DarthTicius. I guess the main thing which was causing my trouble was some way to have a polygon drawing tool in the backend, for non-technical users to add their own polygon shapes along with their marker, within the location field interface. I probably should have been clearer on that, sorry for the confusion!
I’ve moved on to using another solution for this project, though this may still be something that would be useful at some point. It looks like you’ve definitely provided all the pieces necessary to display the polygons on the front-end though, hopefully that will be useful for several people in the future.
