Original User: Scott_Atherton

I am using ArcMap 9.3.1, 3D Analyst/Surface Analyst/Area and Volume Statistics to calculate some statistics on a TIN we have for a lake. The two options for calculating statistics are �??Calculate Statistics above plane�?� and �??Calculate Statistics below plane�?�. It says my Z max is 14.19 and my Z factor is 1. When I enter my Height of plane as 0 and calculate the statistics above the plane it gives me these results:

[ATTACH=CONFIG]13472[/ATTACH]

And when I enter my Height of plane as 14.19 and hit calculate statistics below plane I get these results:

[ATTACH=CONFIG]13473[/ATTACH]

These numbers should be the same should they not be? am I missing something here? Any explanation would be greatly appreciated,

Thanks in advance!

I am using ArcMap 9.3.1, 3D Analyst/Surface Analyst/Area and Volume Statistics to calculate some statistics on a TIN we have for a lake. The two options for calculating statistics are �??Calculate Statistics above plane�?� and �??Calculate Statistics below plane�?�. It says my Z max is 14.19 and my Z factor is 1. When I enter my Height of plane as 0 and calculate the statistics above the plane it gives me these results:

[ATTACH=CONFIG]13472[/ATTACH]

And when I enter my Height of plane as 14.19 and hit calculate statistics below plane I get these results:

[ATTACH=CONFIG]13473[/ATTACH]

These numbers should be the same should they not be? am I missing something here? Any explanation would be greatly appreciated,

Thanks in advance!

Please take a look at this help documentation on Surface Volume. When you are changing the plane, then you have to consider what is being asked. The reason your values are different is that there are vastly different areas being surveyed depending on your data.

[ATTACH=CONFIG]13485[/ATTACH][ATTACH=CONFIG]13486[/ATTACH]