View Full Version : Prorating Elevations
11th Mar 2009, 04:18 pm
Ok my head surveyor just came in my office and was aggervated about his elevations. He brought me a set of plans with elevations and contours, but I have no CAD files good or bad. So I digitized it with my agtek and exported it to AutoCAD 2009 LDD. But I'm having trouble all around. He wants me to "set up a grid" across the parking lot using the design elevations and prorate the elevations over all. My questions is there a better way? Or how should I go about this?
11th Mar 2009, 05:01 pm
Can you perhaps elaborate a little bit? You mean he wants you to interpolate the elevations of the points and create a grid of it?
Might help to post a screen grab or the cadd file for us to peek at too.
11th Mar 2009, 05:41 pm
Well thanks rusty...long time no type.....um yeah I guess thats the word I was looking for, he just kept using prorate and I was trying to grasp what he was getting at. Im going to attach the file I created in agtek, which isnt very good but its something.
11th Mar 2009, 06:00 pm
OK so what it looks like is that you have limited spot elevations for the lot and what he likely wants is for you to interpolate between the elevations you have for the purpose of creating a grid of points based on those elevations you do have. Did he tell you why he's doing it that way? That seems strange to me, but...:unsure:
I suppose you might draw a grid at whatever size he asks for and then add points on that grid...
Lets back up a tiny bit... Did you digitize the contour lines as well as the points?
11th Mar 2009, 06:02 pm
I mean I see contours here, but did you include those in your surface definition?
11th Mar 2009, 06:03 pm
Yes sir I sure did.
He wants a 40 foot grid, with elevations, but really not sure why.
11th Mar 2009, 06:11 pm
OK. I wanted to be sure because the tin lines (3d faces) don't go to the extents of those contours. Heck you may not even need the contours unless he's doing work outside of the parking lot area then he would.
In Land Desktop this is what I think would work:
Create your surface
Add the points to the surface (I notice the points came in as polyline with zero length. These may need to be added as breaklines. If you are unable to add as points then try that.)
Add the breakline(s) to the surface
Add the contours to the surface
Analyze/Review/QC your surface
For the point grid there is an option somewhere in the Points menu to create points on a grid. It will ask you what size grid and you go from there. Be sure to Set your point settings up so that the elevations and descriptions will be automatic so you don't have to fill them in each time. I would give it a description that makes sense like INTPO (for interpolated points) or maybe just CALC so that anyone who opens the file and sees the points will know they are not real survey points.
Hope that helps. Nice to see you back.
11th Mar 2009, 06:12 pm
And of course I have to say it... This would be even better using Civil 3d. haha
11th Mar 2009, 06:16 pm
Well I could do it in civil but Im not to great with that program, and thanks I dont know what happened to me but Im still around. And by the way great write up on the steps thank you very much I got lost there in the dark.
11th Mar 2009, 06:49 pm
No problem. Glad to help. Should the need ever arise for you to learn the program just let me know. I'd be more than happy to get you going with it.
11th Mar 2009, 06:51 pm
Ok I keep that in mind, and hold ya to it....... Thanks again man
12th Mar 2009, 03:32 am
Search the civil 3d help for "Creating a Point at a Surface Elevation"
"this command creates points using elevations that are read from a surface"
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