I signed up here a while ago when it became clear that I would be needing to draw at the very least a rudimentary map for an upcoming tabletop RPG I'm going to be running... but that is more or less as much progress as I've made. Allow me to explain some particulars -

Firstly, I had to figure out what software to use. I have pretty much no money to my person available to blow on fancy adobe products (though a ways down the line I am considering getting that nifty student discount they offer), therefore I was left with a free choice of raster or vector editor. I tried GIMP for a while, but ultimately I decided the scalability of a vector based image would be best (I don't ever intend to convert the image to a raster format so size isn't much of a concern). Well, that, and the guy whose idea I'm patterning my own after drew his map using a vector image editor so I figured if it worked for him it should work for me. Since I'm limited to a budget of roughly zero dollars I decided on Inkscape. I figured hey, I can put a grid down, maybe draw in where some forests and mountains are, and call it a day. How hard could it possibly be?

This is, give or take, where it all fell apart, as the genre-savvy among you probably figured. I need to map an area of roughly 100 miles on a side (assuming a square area) and, while previously I had given some thought to scale, I am, unfortunately, a visual graphics idiot and have become hopelessly lost. What kind of scale can/should I use? Why do the rulers in inkscape still measure by pixels if the image technically doesn't have a resolution? If it doesn't have a real width or height how can I assign a scale? Can somebody please just point me in the right direction and give me a shove?

Thank you all so much for any help you can give