How to calculate area, length, and perimeter of a shapefile
1. Activate theme
2. Theme > Start editing
3. Open theme attribute table
4. Edit > Add field
Name: area
Type: number
Width: 16
Decimals: 3
5. Highlight area column in table
6. Field > Calculate
7. In field calculator double-click on shape
[shape].ReturnArea
8. Table > Stop editing
9. Save edits? Yes
For length, type the following into the expression box:
[Shape].ReturnLength