Hi everyone, I've been working on a 3D map for PC version of GTAV. It's at:
https://www.gta5-mods.com/tools/codewalker-gtav-interactive-3d-map
It now allows entities to be placed and moved, also new and modified ymap files can be be saved. This feature is still in experimental stages, but I would love to hear any feedback on it!
Enjoy! [Edit: Updated screenshots and description]