# How to draw roadway from Center-line survey points?

Traverse PC Land Surveying Software Redo Forums Support How to draw roadway from Center-line survey points?

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• #65781
tdurham
Participant

I have had TPC for a while but have alot to learn! I am mapping a 1300′ section of roadway with a 57.7 meter vertical drop. I am doing one version of the map with a drone and ground control points. But I also want to create a version using TPC. I surveyed the center line of the road from top to bottom (total of 49 points. Could you help me with the process of creating the roadway with proper elevation? The roadway is approximately 15′ wide. The main focus of this output is to show the elevation of the road from top down to the bottom (accident site). I realize this may be slightly different from the normal approach but I think TPC can do just about anything!. The points are roughly 25′ apart so I can interpolate the curves. Any help will be greatly appreciated.

• #65787
John
Keymaster

Yes, you can do that.

1. create the center line from your points

As a rule, we collect points along the tangents and in the curves, but don’t know where the PC’s (Point of Curvature) and PT’s (Point of Tangency) are. If you think you were able to pick out the PCs and PTs and have included them, continue on to step 2. If not, you will need to use the line and curve fitting tools in TPC to approximate the tangents and curves and compute the PC’s and PT’s. Not sure how exact you have to be for this job.

Sometimes, the job or contract requires that we compute stationing along the alignment. TPC has a COGO, Stations routine to put these points in. It even interpolates their elevations.

3. create a 15′ wide road R-O-W with offsets left and right

Select your center line traverse and choose COGO, R-O-W Offsets. Create offset traverses 7.5′ from centerline, both left and right. Let TPC create these traverses for you.

4. now create a new traverse to get the area

Since both R-O-W left and right traverses are going the same direction, I would use the Tools, Sort Points to reverse the order of one ROW traverse, then add it to the other ROW traverse. You now have your area.

Hope this helps. I’ve done lots of these, mostly with very exacting Step 1s.

• #65793
tdurham
Participant

John, thank you for the reply. I have imported my points into TPC but I can not for the life of me figure out how to create the line from the points. I am attaching the screen shot link. Where is the proper method to create the roadway center line from the 49 points so that I can then create the R-O-W offsets?

Thanks!

• #65878
John
Keymaster

I looked at your screen shot. You have already done Step 1 above. The centerline points are in the one and only traverse 2019-09-01 Alabama Blue Dots…

So now you are ready to work with that traverse to do steps 2 – 4.

In the Traverse Manager, choose COGO, Stations… for Step 2 or ROW Offsets for Step 3 and you will be on your way.