"Yup" and "should be fine" are the answers to most of your questions.
Yousei's editor comes packaged with his "ffiv.txt" document, which is the most complete ROM map to date for the game. World map data is in the same place in versions 1.0 and 1.1, so after making your edits, you can just copy the data directly from one to the other. ("World map formation pointers" and "world map formation data" or something along those lines is how he refers to the data in question in his document - and bear in mind that Yousei's offsets assume a header, so subtract 200(h) if you are headerless). I've only made edits that, in effect, shrink or maintain the amount of space used, so I can assure you FF4kster will be OK with either of those possibilities. Don't know what will happen if you increase space. It depends on what follows world map formation data in ROM. It's worth noting here, though, that Yousei's utility will resize (expand) your ROM automatically if you expand the formation data beyond its natural limit. The process will, in effect, relocate ALL of the world map formation data to a new bank in ROM. this will a) make it harder to copy into your own project and b) make it incompatible with FF4kster, assuming you keep the expansion. So I'd recommend not using more than the originally allocated space.
Oh, yeah, and the format is one byte for a single tile (say, "19" IIRC for one tile of ocean on its own) and two bytes for more than one of the same tile ("99 03" for four tiles of ocean, where adding 80 indicates the multiple and "two" is signified by 01, etc). The only difference in format between world map data and location map data is that in locations, a row is terminated with an "FF," but it is not in the world map (the next row simply begins where the previous row ended, and the row pointers take care of indicating the terminus). But that last bit is porobably more than you need to know if you're using yousei's editor.
Topic: Overworld Map Editing Questions (Read 749 times)