How to align 2D survey with mesh from surveyors data?

[srdavids]

Hi All,

I typically just manually create topo mesh by tracing lines from the survey, but wanted to try the "Place Mesh From Surveyors Data" and see if it would save me some time.

I asked the surveyor for a .txt or .xyz of the topo data and they sent .csv with coordinate points, which I literally just renamed to .xyz to get the import working. He did include the property boundary points at the end of the file, which I removed as they were interfering with the mesh creation:

 

But now that I have the mesh in the file, I can't for the life of me figure out how to align them. There aren't any apparent landmarks to align to. I would think I could somehow use the property corner data but I'm not sure what to do with it. Is there something I need to specifically request the surveyor to do on his end? Am I missing something?

Thanks!

[Miha_M · Accepted solution]

The survey plan and .xyz data should be aligned, if you import them. Did you get the topo data extracted from the same survey plan or does this data come from a different source?

All might depend on your workflow as well. I usualy import the Survey plan via xref. Then I import the .xyz via  File > Interoperability > Place Mesh from Surveyors Data. The position of both data sets should result in aligned surveyed position points. The same should work if you use (and should use) the Survey point tool.

[ryejuan]

Did he started the modelling the topo mesh by the origin or did he use the location the surveyor gave him?

[srdavids · Accepted solution]

Miha! Thanks for the reply, this did eventually lead me to the solution. The survey point was SUPER helpful, I wasn't aware that it existed.

So here's what I did to align it:

• Imported the Lidar data via Place Mesh from Surveyor's data and placed via 'Original Location'
• Brought in the dwg survey via xref to it's 'own origin', but it seems the surveyor did not have the same origin in his CAD file as his topo data. It was something like 3 million feet from the topo data
• Turned on the Survey Point and moved it manually by entering the coordinates of one of the property corners that the surveyor had manually included at the end of the Lidar data file.
• Picked a property corner on the DWG and moved it to the new survey point and it looks like everything is aligned!

Thanks for the help!

[Miha_M]

I'm happy to hear that you solved the problem! You should address this issue to whoevery the surveyer was. The positions should get aligned without such workarounds.

There could be another reason for that as well. In my country we have transitioned from the  D48/GK to D96/TM coordinate system, and those two don't align. Maybe your two data sources were based on different systems? 

[srdavids]

That's an interesting point. I'm not sure what coordinate system he used and I'm not close enough to this particular surveyor to ask him to spend his time investigating. I think I have a better understanding of what to ask for next time though. Thanks again!