[Inkscape-user] global unit system and transformation

Hi all,

I've just started to use inkscape a few days ago to draw a map. But for this I would like to have a user defined coordinate system as my country outline is in "degree". It would be really nice if I could use the geographic grid (ie. for adding point symbols at 19°N, 101°E). But I would need to set somewhere a global transformation to map that system onto the drawing area: 1° equals 3cm on paper, and the origin of the paper =18°N,99E for example.

Perhaps something like that is already included and I only couldn't find it?

Thanks Wolfgang