Using the Measure tool, I see there are 4 Measurement modes, including 'Geodesic' which I think of as being related to "Geographic coordinate systems", and 'Planar' which I think of as being related to "Projected coordinate systems" ...Is this concept correct?
...But, what dictates which of these are available to use? I ask because sometimes I see 'Planar' grayed-out -- even when the Current Map Coordinate System is set to a Projected Coordinate System.
With this, I've sometimes noticed that my measurements are quite different than a colleague for the same thing ...even over short distances. I also notice differences with this same person/computer when 'calculating geometry' for a field ...so there appears to be some relation here?
