What is the best practice to switch the coordinate system of a dataset to a different one?
For example getting data in ETRS89/DKTM2 and switching it to ERTS89/UTM32.
The obvious answer is to use the Change Coordinate System command - however you do need to be really careful using this as changing coordinate systems will shift data in the project and the important thing is that you have to check that the shifted data is correct after the coordinate system has changed - don't just assume that it will get it right - it really does depend on where the data came from, what has been done to it before getting to "this point" and also whether the Coordinate systems are standard Projections and Datums or if they are self created site calibrations.
For example when you set up a site and have a Base Station created with a Here position, then the error in the base is computed when you do a site calibration and it adds extra X Y Z shifts to the data - when you start using that data with regular Coordinate systems the Here Position error can sometimes screw up the results so you have to be careful. It should always work but I know from experience that sometimes things can go wrong when people start changing coordinate systems on projects - important thing is to make sure you check the results with known data locations.
Currently we export 2 two points of the drawing to a global .csv - import them and select the new coordinates system.
Then import the original drawing, and use the "Move/Scale/Rotate Object by Points" to move the drawing based on the 2 points imported from the global .csv.
But surely, as we now the global coordinates of objects whether they are in coordinate system Denmark(ETRS89) - DKTM2 or Denmark(ETRS89) - UTM32, or any other for that matter, this should be possible with just the push of a button?
But the Change Coordinate System command doesn't swap/convert the the grid coordinates as far as I've seen?
In 9/10 if not more, our customers are using standard Projections and Datums, no local calibrations.
Specifically, the problem is when they get data from the designer in Coordinate System X, but data for existing installations are in Coordinate System Y. Or they did a survey in a "wrong" Coordinate System, that doesn't match what they got from the designer afterwards when they need to compare.
Could you provide me with an example data set with Coords in the two
coordinate systems and the CAD Data so I can walk through exactly what you
are doing and I will try to get a process written up for you.
I will need
1) Coordinate System 1
2) Coordinate System 2
3) points that are the same point but in the correct location in Coordinate
System 1 and Coordinate System 2 (so I can verify)
4) A CAD Data Set that you want to transform from CS1 to CS2
You gave me your current process - I will try to follow through what you
are doing and will discuss internally with Survey how they would expect you
to manage this - they take care of all the Coordinate System stuff and
while I use it, in N America most people Calibrate rather than using
Coordinate Systems and I dont see this issue of wrong coordinate system
that often (it does happen but normally the surveyors sort it out so it
doesnt get to me as an issue)
Happy to help - just need to map through the process for you
Send me a Zip with a description please and I will loo at it next week
On Fri, Aug 31, 2018 at 5:58 AM Lasse.firstname.lastname@example.org <email@example.com>
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