I would like to autocalculate area (acres) for a shape file that is in UTM zone 16 CRS.
I have tried the "Vector|Geometry Tools|Add/export geometry columns" and also the field calculator. The first gives me a warning saying
currently QGIS doesn't allow simultaneous access from threads to the same data source. Make sure your layer's tables are closed. Continue?
When I click
YES, it creates two new columns
- The AREA column is mostly 0's with a few values such as 2e-06 and so on.
- The PERIMETER column gives mostly values along the lines of .003526 and so on.
- What is the warning it is giving me and why are the values so sporadic?
- Also when I use the field calculator tool, it seems to give me values close to what the field area should be but when I click SAVE EDITS all the values turn to 0's. What am I doing wrong?
Thank you in advance for your help.