That's why I prefer using a vector app like Xara to create my maps, as I generally create maps at 24" x 36" without any notion of pixels at all. Working in vector is not reliant on a specific pixel dimension as any raster application requires. When I am done I can export to 100 ppi for VT uses or posting on this forum, and I can still print at full scale 300 dpi from the same map original without making changes at all. PPI is determined at image export only. The map that I created for Paizo was a 36" x 48" map setup, but then I hand-drew 4 each, 18 x 24 inch sized sheets that were scanned and composited to the "E" size. Of course sending a version to Paizo for review, I only export as a 96 ppi image - as they will only look, and not intended for print.