Map transform to other projection

[guillaumech]

Hello everybody!

I've few questions, I try to transform an image for specific projection. I've a map of France (or any other countries), and I'd like transform this map in an other projection, as Mercator or Lamber. I seen "distorting" option, mainly "distor persective", but Mercator distortion follow a no linear distortion function, but this function : http://upload.wikimedia.org/math/8/5/f/ ... b286de.png
You just need the center coordinate of map for this function, and each points on the map.

I don't know if it's avaible and possible... Thank you very much for your future answers.
Guillaume.

[snibgo]

Doubtless you could do it with "-fx" but it would be agonizingly slow. With a compiled program you can get virtually instant results from any projection to any other projection.

[guillaumech]

Certainly, but I use already IM to build my map, with converting data in pgm format and after interpolate values to obtain a large map. The pgm format is linear so it's easy to resize it. Imagine a grid of data on country, linear data grid. I take all data to generate a color map with interpolate values between baseline data.
If I project data before interpolation, I will not obtain a linear grid...