A 7 level standard deviation gives me only three clases?

[tonnot]

I have a surface style (standard deviation)  for contour with a range of 7 classes.

Ok, if I apply this to my surface (it is a fine built surface) I have only three intervals 

Whats can be happen ? 

Thanks

[dgordon]

did you goto the analysis tab of the surface properties and sample the ranges?

[tonnot]

I have always 3 ranges...  

Even If I write 7 and click on run analisys I get 3 ranges.... 

I'm using contour ranges option. 

Maybe I'm using something without sense? 

Thanks !

[dgordon]

I don't generally use the contour analysis, but i'm guessing that if my surface is set to show contours ever 1ft and my surface has a min elevation of 770.50 and a max elevation of 773.50   I might expect to only get 3 ranges since my surface only contains around 3 vertical feet of information.

[tonnot]

I have heights from 0 to 16 meters.

I'm using this : 

[dgordon]

I set up a surface similar to yours and I now understand what you're seeing.

the only way I was able to get the analysis tab to sample 7 different elevations was to use the quantile type.

here is the descriptions of each type from acad help.

I hope this helps.