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

[waldronate]

If you want to go from FT to Photoshop and then repeat that a few times, there will absolutely be an amplification in the distortion at every round trip. If, however, you are using FT to measure elements done in a Photoshop map, you can use the map in FT without worrying about distortion too much as long as you keep to the limitations discussed earlier. The idea of keeping your maps small and putting them near the equator for measurement is that you can safely ignore projection issues when measuring distances. Doing other things with the map will require you to pay attention to things that had been able to ignore in the simple case.

If you want to import a large section of your world into FT, then you will very much need to worry about distortions in your maps. You will need to be aware of the projection for your input data and then convert that data to Equirectangular for use in FT. That topic is a little more complex and would take a bit more discussion to resolve, I think.

[Elros]

If you want to go from FT to Photoshop and then repeat that a few times, there will absolutely be an amplification in the distortion at every round trip. If, however, you are using FT to measure elements done in a Photoshop map, you can use the map in FT without worrying about distortion too much as long as you keep to the limitations discussed earlier. The idea of keeping your maps small and putting them near the equator for measurement is that you can safely ignore projection issues when measuring distances. Doing other things with the map will require you to pay attention to things that had been able to ignore in the simple case.

If you want to import a large section of your world into FT, then you will very much need to worry about distortions in your maps. You will need to be aware of the projection for your input data and then convert that data to Equirectangular for use in FT. That topic is a little more complex and would take a bit more discussion to resolve, I think.

I understand, in case i need long journeys I will look for a narrative expedient.
Thank you so much again for your time.
You were really kind, I will try to limit the damage from distortions trying to remain vague on the measurements, if as you said you, the damage of distortions is only 10%, is acceptable.

[waldronate]

I'm glad that I was able to be of some assistance. FT is one possible solution for the things that you said that you want to do and there are (as others said) other tools that can be used to get the same results. Best of luck with your measurements and feel free to keep asking any cartography-related questions here on the guild.

[Elros]

I'm glad that I was able to be of some assistance. FT is one possible solution for the things that you said that you want to do and there are (as others said) other tools that can be used to get the same results. Best of luck with your measurements and feel free to keep asking any cartography-related questions here on the guild.

Thank you very much, if I need any more advice I will certainly ask.
Thanks again for your time