Comment 22 for bug 1405292

The 72.5mm one is actually 72.31945 mm once Inkscape opens it. In Adobe Reader I see it as 2.85 x 2.85 inches (72.39 mm). In Inkscape trying different units finds 205.00001 pt, and not near any other nice numbers - whole integers, simple fractions in pixels, mm, or inches. Are you wedded to that size? I have not seen this resizing problem with an A4 which is 210 x 297 mm. 297/4 = 74.25 mm, which is pretty close. Can you generate the map at that size and then open it in Inkscape? If it isn't very close to 74.25 then there is something slightly off in the sizes your map software is generating.

Note that
72.39 - 72.31945 = 0.070550
0.070550/72.39 = 0.000975 = ~.001

That suggests to me that there may be a 1000px size in play somewhere and you are seeing rounding errors of that magnitude
as a result. (Speaking here from experience - EMF has a pixel size basis too and if the value is too small similar problems arise.) If you poke around in the generating software and find an adjustable number of .001 or 1000 try increasing the resolution by 10x, that might minimize the resizing issue. Otherwise, if generating an image size of 1000 px is an option, try that.