I select a point in edit mode, and it gives me some reasonable xyz Vertex values in the "Transform" area (for example 955, -455, 100).
I select another point and I also get reasonable values (for example 517, -471, 76), 100s of units from the first point. When I go to Grease Pencil/ Tools/ Ruler Protractor and try to draw a ruler between these two points to get the exact distance, I get a very small value instead (like .652). Shouldn't the ruler be giving me the difference between the vertices? I thought this might have to do with some local vs. global coordinate issue but I can't make any progress on that.
[Since I am prohibited from posting a comment I'm not sure how to add information to my question, aside from editing my initial post, so that is what I am doing.]
I have attached another image showing that the scale of the mesh object appears to be 1.0. Since the mesh object scale is 1.0 I cannot understand why this is a local vs. global scale issue (even though that's what I suspected this problem ultimately would be related to).
Generally, even if this is a global vs. local scaling issue, how could I get the ruler to show distances using the object's own scale? I don't see any option in the Ruler/Protractor that would tell it to use the object's own scale for measurement.
Here is an image that I think shows that the scale of the object is 1.0:
Based on Carlo's suggestion I examined the object hierarchy more closely. The meshes I was looking at have a scale factor of 1.0, but the meshes are part of a 'Model', and the Model does have a scale factor of .001 associated with it, as this screenshot shows:
The model was imported from an Autodesk .3ds file, by the way, and that is how this scale factor was introduced into Blender during import.
So at this point I am at least comfortable that I understand what is going on, though I'm still not sure how to make Blender do what I want. I may try to figure out how to rescale the object to a factor of 1.0 so that my blender units agree with my model and the ruler will give me "real" values.