Map Tool. Sorry. My world building has progressed to the point of using GIS tools in my games. Though, funnily enough I do have QGIS installed on my work laptop. It would be interesting to play around with how to use it in my world building. If I was doing a modern or SciFi game, I could totally see using QGIS for marking up maps.
It would be most impressive if you are doing a modern game like Delta Green or futuristic game like Shadow Run. There are lots of free satellite images, you can match these with various overlays and shape files to show and reveal things and you can mark up the maps. If you want a large region, continent, or the whole world to be your area of exploration, using QGIS would be an awesome way to display that and reveal information about locations as you explore.
If you are homebrewing your own worlds, it would be a lot of work, but if using the real world and pulling from open source images and data, it is just the learning curve to learn the software, but after that it would be quick to load maps, shape files, and data and to mark things up.
The image files, howver, are huge. Like I just opened one set and the main B&W sattlelite image is half a gigabyte. The overlay file is 161 MB. You'd need a good amount of space on your hard drive and you'd only be sharing via screenshare.
I'll probably never do this, because I only have time for my D&D campaign and I'm looking to decrease my prep time. But I can imagine some cool things one could do with a QGIS or some other GIS software. QGIS is open source. If interested, you can download for free here:
Discover QGIS
Good sources of free GIS file sets can be found here:
(large, well-categorized list of sites offering free GIS data)
Turbo-charge your search for free GIS data with this list of 10 free, downloadable global GIS datasets from highly reputable sources - vector and raster.
gisgeography.com
GIS Geography's list of the 10 best sources of free GIS data
maptools.com
