Civil3d and Surveys

[atelier.absinthe]

Hi everyone, I am a relatively new Civil3d user, I have a probably basic question for you experts:
with Civil is there the possibility of superimposing a GPS survey, with a TPS survey? in such a way as to have automatically oriented the TPS survey on the GPS coordinates (Wgs84)?
Thanx so much

[Pointdump]

Hi David,
GPS I've heard of. But what is TPS? And more details please on what you want to do.
Dave

[atelier.absinthe]

TPS: total station 🙂
what I would like to do for example would be:
- I have the GPS survey of 3 points with real north orientation (IMG.01) 
- I have the survey of the total station, of the same 3 points that correspond to stations A, B, C, from which then come the detailed points A1, A2, A3, A4, B1, B2, B3, C1, C2, C100 etc etc which obviously have an orientation relative to the orientation points (IMG.02) 
- I wish I could rotate the total station survey on the GPS survey with calculation of the polygon and relative error It's possible?

[Anonymous]

TPS must be TotalStation Positioning Survey? Or Tacoma Public Schools, one of the two.

The best way to do it, of course, is to have known GPS coords for your total station survey before you occupy the control points.

In C3D, assuming you called your total station control some arbitrary XYZ coords, bring the points into the drawing, then ALIGN the TPS coords on to the GPS coords. You have to do this in 2D! If you have point styles that use actual elevation for the marker and do a 3D ALIGN you'll get bad results. Either set the marker style to be a fixed elevation or use temporary construction lines with the end Z's set to 0. This gets you horizontal location.

For elevation or vertical adjustment you can either use C3D to edit the points (EDITPOINTDATUM) or an AutoCAD MOVE to MOVE the points the appropriate vertical distance.

This is kind of a backwards way to do it (see above, best way to do it. Your instrumentation should have checks built in that alert you to errors when orienting the total station)- that is, doing it in C3D. It should work theoretically, but (in C3D) you better check check check, every point you can that is common to both surveys. Check every backsight shot. You'll be basing the entire TPS survey on just two points - there is no redundancy except shots on known points. Expect error but hopefully it is minimal and within acceptable tolerances.

[Pointdump]

Thanks for clarifying with screen shots.
@Anonymous's excellent and well explained advice is the easiest way. I have another way, cutting edge, which involves a custom Affine Projection. Can you post 2 drawings or even just both point files?
Dave

[Anonymous]

https://en.wikipedia.org/wiki/Affine_transformation 

Whoa. You're a better mapper than I, Mr Stoll.

BTW Euclid (c. 287 BC – c. 212 BC) onward, and is usually referred to as "ὁ στοιχειώτης" ("the author of Elements"). Cutting edge, indeed!

[jefflambert9091]

If you are just exporting points from the TPS you can start in any system and once you have your control from your GPS you can plug the new points in the TPS job and then export. If not, you can bring in the TPS via survey database and then rotate translate. It does a vertical as well. We GPS every job, get the ground coords for the starting control and then plug them into the Collectors. 

[atelier.absinthe]

ok !! I understand you were all really kind to explain the matter to me!
now, I will do some tests and in case I will carry this post forward in such a way that maybe it can be useful to someone else.
obviously, if you also have video tutorials that can explain the thing operationally, it wouldn't be bad!