AFAIK, you can convert maps between FO1/FO2 format with
DIMS mapper and then open them in BIS mapper. Be aware that it's buggy and incomplete. Also not sure if it converts everything correctly.
If you intend to use this for FOnline, you're going to have a lot of work to do. About two years ago, FOnline mapper was compatible with FO2 format, so you could convert FO1 maps to FO2 with DIMS mapper, then load them into FOnline mapper, but this is not possible anymore. So the only way is to hunt down an old versions of the mapper from someone that has them all saved, and then start opening and saving the map until the latest.
Or, you can start recreating the map from sight, probably a lot easier, unless it's Hub or NCR.