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Transferring points from Trimble Connect to Terraflex

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  • 1.  Transferring points from Trimble Connect to Terraflex

    Posted 02-18-2025 15:10
    No replies, thread closed.

    I'm a non-professional (hobby) user, using a Trimble Catalyst DA2 to locate buried survey stations (OS triangulation stations from half a century ago) in the UK, using TerraFlex. The process needs sub metre accuracy. I've been copy-pasting the Eastings and Northings (1cm precision) across from a website, which works well but is a little fiddly. It would be more convenient to get the points across in bulk. I can import them to Connect via a kml file, and send them to TerraFlex as forms. However, I quickly discovered that the forms aren't accurately located - perhaps rounded to the nearest metre.

    Advice appreciated on whether there's a way to transfer points to TerraFlex preserving 1cm accuracy. My manual process works OK - but it's manual, and tends to rely on internet being available on site.
    Thanks
    Rob Woodall


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    Rob Woodall
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  • 2.  RE: Transferring points from Trimble Connect to Terraflex
    Best Answer

    Posted 02-19-2025 05:45
    No replies, thread closed.

    Hi Rob

    What a great hobby. 
    Sounds like a datum shift here. OS stations are based on OSGB36 ( equivalent to ETRS89) and KML uses WGS84. 
    There is a difference between these two datums In the ball park you are describing so you'd need to perform some sort of transformation to remove this error

    We can take this offline (happy to DM you) but I'd suggest the following workflow:

    1. Download the QGIS (this is free open source GIS SW)
    2. Get your OS Grid coordinates in a CSV format -  PointCode, Description, X,Y,Z 
    3. Open QGIS > Data Source Manager > Delimiter text - follow this video here as an example how to import and georeference this Importing CSV (Excel) Coordinates into QGIS
      • NB the Geometry CRS (Coordinate Reference Systems) you need to define is  EPSG 27700 - OSGB36/British National Grid
    4. Once Imported you can save the layer as a vector file choosing SHAPEFILE - again this is at the end of this video Importing CSV (Excel) Coordinates into QGIS
    5. This shapefile can be zipped then Imported into Terraflex and should be correctly georeferenced 

    Give me a shout If you need any further help and I can help you get setup



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    Tom Harrison
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  • 3.  RE: Transferring points from Trimble Connect to Terraflex

    Posted 02-19-2025 14:06
    No replies, thread closed.
    Thanks Tom!

    I'll give that a try.

    Rob



    Original Message


  • 4.  RE: Transferring points from Trimble Connect to Terraflex

    Posted 02-20-2025 17:00
    No replies, thread closed.

    Hi Tom

    I think that worked, after a few wrong turns along the way.

    The first dataset I transformed, returned a message relating to the below alternative. It seemed to refer to a small number of objects. The majority if not all (there's a drop down) should I believe be EPSG 27700 OSGB36. 

    Many thanks for your help.
    Rob

    I'll see how accuracy looks over the weekend, i.e. whether the forms are taking me to the expected 1cm coordinates. 

    The forms method is rather cumbersome to use for a large dataset, and the 1000 form limit is a nuisance. They're all on TerraFlex, though, and hopefully correct.

    Many thanks
    Rob



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    Rob Woodall
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    Original Message


  • 5.  RE: Transferring points from Trimble Connect to Terraflex

    Posted 02-24-2025 12:54
    No replies, thread closed.

    Hi Tom

    Your suggested workflow worked well. I imported c. 9300 points in 10 batches. Not that I'm likely to visit them all!

    As a check, the forms locations matched the 1cm coordinates pasted into Terraflex for the few where I used 1cm Catalyst, when I tested them this weekend.

    It's impressive that these buried survey points installed in the 1950s are pretty close to the Ordnance Survey's calculated locations. 

    Thanks again.
    Rob



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    Rob Woodall
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    Original Message


  • 6.  RE: Transferring points from Trimble Connect to Terraflex

    Posted 02-25-2025 04:45
    No replies, thread closed.

    Lovely stuff Rob, glad to be of help. Good luck with the project

    Tom



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    Tom Harrison
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    Original Message