So all of the guides to building a world climate seem to require having latitude and longitudinal lines. My problem is I"m having trouble finding a way to put them on my map as I'm not sure how to convert pixles, mm, or other measurement units used by inkscape into degrees of latitude and longitude. Should I just put an equator down then divide my page into 3rds and label each third 60 degrees, or there a less crude method of doing it?