点一下栅格计算器的帮助，会有下面的解法
To calculate area:
Dim Output as double
Dim pArea as Iarea
Set pArea = [shape]
Output = pArea.area
To calculate length or perimeter (depending on whether the features are lines or polygons):
Dim Output as double
Dim pCurve as ICurve
Set pCurve = [shape]
Output = pCurve.Length
To add the x coordinate of points:
Dim Output As Double
Dim pPoint As IPoint
Set pPoint = [Shape]
Output = pPoint.X
To add the x coordinate of polygon centroids:
Dim Output As Double
Dim pArea As IArea
Set pArea = [Shape]
Output = pArea.Centroid.X
新建立一个字段，在字段上有一个caculator geometry 在点一下，会看到什么……
导入到GDB中，又会看到什么……
utility下面有一个工具也，看到了吗？