Problem: The Calculate Geometry tool is disabled on certain fields
When attempting to calculate geometry for certain fields in an attribute table, the tool is disabled.
The field chosen is an inherent field of the feature class managed by the geodatabase, for example, in a polygon feature class, there are four fields that are unavailable for editing; OBJECTID, Shape, SHAPE_LENGTH, and SHAPE_AREA.
When a new line feature class is created, an additional field is automatically created to record the length of the line. Likewise, when a new polygon feature class is created, two additional fields are automatically created to record the length (perimeter) and the area for each polygon feature. These are required fields and the properties cannot be modified.
Solution or Workaround
To perform Calculate Geometry, add a new field. The new field automatically records the properties of the feature.
Use the following procedure to create a new field and perform Calculate Geometry:
- Start ArcMap, and right-click the desired feature class > Open Attribute Table.
- Click Table Options > Add Field.
- Under Type, select Double as the data type to allow possible decimal points.
- Click OK.
- Right-click the new field header > Calculate Geometry.
- Specify the desired calculate geometry property, the coordinate system, and the desired measurement unit to be used, and click OK.
- ArcGIS Help: Calculating area, length, and other geometric properties
- ArcGIS Help: Fundamentals of field calculations