The lat/lon ruler does not fit the lat/lon grid on my map. Why not?
If it is way too long east-to-west… Remember the lines of longitude converge at the poles. That is to say the further north or south you go from the equator, the closer together they get. You need to use the ruler on a diagonal to compensate for this. Instructions are here. If it is way too long north to south… Not all maps use the same size lat/lon grid. You may be using a 7.5 minute ruler with a five minute grid spacing. In this case, only use the portion of the ruler from 0 to 5 minutes. If it is just a bit too long north to south… It turns out that the lines of latitude also get just a bit closer together as you move north or south from the equator. This is because the earth is an ellipsoid, not a sphere. MapTools lat/lon rulers are sized for an exact fit at 40 degrees north and south of the equator. For most of our users this will make the ruler about a millimeter too long. Most folks never even notice, and the results they get are well with in their accuracy requirements. t
