Program to calculate size of map and point to point distance.

[Elros]

If you're only interested in distances and your area of interest is less than 4000km across, importing that are into FT along the equator will let FT treat it as if your flat map is in a form that FT can understand (i.e. the Equirectangular projection). You're not saying that it's not cold. It's just that for convenience of measurement, you're treating your map in a way that makes it easy to import and measure in a specific tool (FT in this case). Using FT isn't the important part here: putting your map at the equator lets you conveniently ignore the projection when importing the image into FT.

If you have drawn a map that's just a few thousand km across, you can declare that it's in a projection that is "flat enough" to use a regular ruler on it and you'll likely get less than 10% measurement error (10% measurement error is probably less than the error in the original cartographer's survey for most medieval-level fantasy settings). If you later want to paste that map onto a globe, then you'd need to declare what that projection and center of projection are. If you want to use FT as a tool for measuring distances on such a map with that map positioned on its correct place on the globe, you'd need to reproject the base map to an Equirectangular map so that FT can properly measure distances. It's not hard to do, but might well be beyond what you need at this time ( http://fracterra.com/ReprojectImage.zip is a program that will let you graphically reproject an image in a number of projections back onto the Equirectangular image that FT wants ).

I hope that make sense. My earlier recommendation to put your map at the equator was purely to make it easy to import into FT. Being more correct with measurements FT requires more complexity in putting the map into FT.

Good ,this applies to maps smaller than 4000km. So most of my problem are solved i think .

If you later want to paste that map onto a globe, then you'd need to declare what that projection and center of projection are. If you want to use FT as a tool for measuring distances on such a map with that map positioned on its correct place on the globe, you'd need to reproject the base map to an Equirectangular map so

Do not risk distorting the image?
That is if I take a continent from an equirectangular projection, I edit it with photoshop, if I then paste it into the FT and declare it equirectangular again, don't I risk distorting it even more?

What if i had to draw a half-hemisphere route?

Thanks, you are really kind