Invert Elevations on Survey Collected Points

[mpayne]

In performing a topographic survey we often locate structures such as sewer manholes. Typically the top of the manhole is located by survey and the distance from the rim to the invert of the structure is measured. This information is in the form of a manual note or added to the description of the point. For example a PNEZD (comma delimited) format would look like this: 1,100,100,100,SSMH,5.82 This would be point number 1 with a northing, easting and elevation of 100. The description of the point is SSMH and the following number, 5.82, would be the measurement from the point where the shot was taken to the invert.

This data is then read by the CADD operator and text is added reflecting the invert calculated by subtracting the manual measurement from the elevation of the located point. I reached a dead end on utilizing the Expression in the label style because the User Defined Properties that I created to store the manual measurement could not be used in an Expression. Has anyone found a way to extract the measurement from the description and automatically create the invert elevation? Thank you.

[sinc]

You should be able to do that with custom programming, as long as you are on Civil 3D 2009 or later.

Other than that, I don't know of a way inside of C3D... One option might be to figure the inverts in Excel before importing the points. Then import the data into UDP's, if you can get that to work properly.

[brian.hailey933139]

One option might be to figure the inverts in Excel before importing the points. Then import the data into UDP's, if you can get that to work properly.

What I was just going to recommend.

[mpayne]

Thanks guys I appreciate you taking the time to respond. I did not think that such a function was available in C3D but if it existed someone in this community would know.

[Jeff_M]

Thanks guys I appreciate you taking the time to respond. I did not think that such a function was available in C3D but if it existed someone in this community would know.

Hmmm, I was able to get the point shown in the attached picture using a UDP & an Expression. Did you make sure to set your UDP to be of a Double type? Then have the expression return an Elevation? Or are you trying to do something else & I completely missed the point?

[sinc]

Ah, silly me... I didn't actually try to do it.

I was able to replicate what Jeff did, and it seems to work fine.

Just beware that there seems to be a problem with UDPs in C3D 2009, if you are using drawings created in earlier versions of C3D, or if you are using a template created in C3D 2008 and earlier. The problem is that UDPs on Cogo Points can "forget" their values when you close and reopen drawings. I have not yet seen this issue in any drawings created from a new template created in C3D 2009. And the problem appears to have been fixed in C3D 2010.

[Jeff_M]

Well, after some discussion via email with Mike, we figured out that my solution only works with Points imported via the Points commands. It does NOT work with the Survey database Import Points, as Survey Points do not have UDP's to work with. So the data never makes it from the point file to the Survey database.

Since this is the Survey forum you'd think one of us would've caught that little tidbit. Oops!

Off to the Wishlist forum to add the "Can Survey points get some UDP lovin' too?" thread.

Jeff