labeling spot elevations from surface with expression

[Hidden_Brain]

for the surface spot elevation style, trying to set up an expression, that will basically be like:

if surface elevation is lower than -1, or higher than +3, return surface elevation, else return nothing ("" in MS excel terms). i am tryiing to use an IF statement, but not hainvg any luck, especially with the 'return nothing' part. any feedback will be greatly appreciated. thanks

[Sinc]

Expressions are very limited.

I think, at the moment, the only way to do what you want is to use an Expression for the text height.  Set it so that if the elevation is within your acceptable range, it returns a valid height like 0.08"; otherwise, return a really small value like 0.0001.

The caveat to this trick is that it often interacts badly with background masks, so you may not be able to use background masks.

[Joe-Bouza]

would setting an elevation band for the range to label work?

Joe

[Joe-Bouza]

I believe elevation banding will do the trick. I tried both and limiting the surface elevation during build appears to be unfaithfull to the original surface.

Joe

[Hidden_Brain]

in this particular case, i have FG shots from surveyor that i would like to compare against my FG surface. it is true that to see the difference, i can run a banding on the difference of the 2 surfaces, but in my case, i picked using surface spot elevations exactly on the locations of the surveyor's as-built FG shots. i cans still do this w/o the expression, but lets say if my tolerance in Z is 0.2', then after setting up all spot elevation labels etc, i will have to visually compare the surveyor's FG shot Z values against my spot elevations. i was hoping to somehow be able to hide the unnecessary spots, but looks like, i do not have a choice. thanks for your feedback though guys, really appreciate.

[andrewpuller3811]

As sinc said, get your expression to return a value based on the surface difference as a text height.

If it is in the range you want to show, set the return value to a normal text height for you and otherwise set the return value to very small, 0.00001 or something similar.

I do the same thing to have slopes show percentage up to 10% and then ratios after that (I.e. 2:1). Both labels are always there, but one or the other is very small.

They appear on screen as a dot, but when you plot they are actually so small they don't plot.

I have used the same label style and expression for the exact situation you are try to work with.