After a bit more experimentation with a smaller project…

I think this situation arises from a map made from two survey centrelines (no scraps or maps in the map definition).

With maps on

M -8999999999999999900000000000000000000000000000000000000000000000000000000000000000000000000000000000.00 DwarfsDoorElev290Map@ (Dwarfs Door<br>Elevation looking 290 deg)

S   749.01  @ ()

S   732.25  @ ()

With maps off

S -8999999999999999900000000000000000000000000000000000000000000000000000000000000000000000000000000000.00  @ ()

So the code needs to test for and either filter out centrelines and maps comprised only of centrelines, or better, correctly determine their name and namespace.

Bruce