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hello billy, fellow surveyors and my friends: 

when I export cad lines to google earth I am getting an offset error of 5 meter why

why rtk position not matching with google earth?

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  • Hello,Raymond,  Check this search page out. https://www.google.com/search?client=opera&q=export+autocad+lin...

    export autocad lines to google earth - Google Search
  • YES MY FRIEND BILLY AND ALL MY PRECIOUS FRIENDS ,MY COORDINATES ARE IN UTM 0.9996 SCALE ,ZONE IS 37Q ,I AM GETING ERROR OF 6m , I am attached here my kml file friends ,please check it.......I am double checked my data every thing is ok ,is there any way to make accuracy near to 1m ,is there any google earth map calibration like that...........

    • Hi, Raymond.  Most of these replies are correct - Google Earth is not survey quality imagery.  The satellite swaths they acquire are wide range & relatively low resolution for speed and cost, so what happens is that if you're generating data on a known coordinate system that happens to fall directly below the satellite path, it will rectify very well.  But the further your data happens to be from that directly under that path, the more dramatic the distortion of the image.

      I use an older version (2012) of Civil 3D to do these image drapes.  I set your dwg to  UTM WGS84 Zone 37N and the CAD came in to GE exactly where yours does.  So I physically moved all of your data in CAD 7.0m west and 5.0m north and got the following (attached).

      Looks pretty but I wouldn't design much off of it.

      Bottom line is: what you've done is as good as it gets with Google, but you can man handle it if you want.

      • files attached

    • Dear Raymond
      What is the final product you are looking for?

      If you want to do a kind of urban cartography with google earth, it will be very low accuracy.

      Best

      • SIR JUST I WANT TO OVERLAY THE CAD LINES WITH IN 1 OR 2 M ACCURACY

  • Hi Raymond

    My personal experience exporting osgb36 ostn02 coordinates (UK) achieves much better accuracy than 5M, closer to 0.5M. The key thing for me is to make sure the drawing units are correct, any scale factor inherent to the original coordinate system has been reintroduced and of course to ensure the appropriate coordinate system is assigned to the drawing.

    Where are you working? Perhaps the UK grid system is a better fit to the GE projection
    • Hi Everyone,Raymond is in Saudi Arabia ,but i think a lot of bases has been covered,but there,  is where his work is, the data i have only works for North America.

  • Raymond

    My experience with Google Earth in south america is really good, but you can not expect to much.

    There ara zones that can be shifted far as 150 m (localy).

    But Google don't use UTM, use Global TM with K =1 in the center meridan.

    Best

  • google earth is not a scientific software simply runs a mosaic of images that do not necessarily should be a maximum degree of precision and that if it is the exact point, can the problem is in on google.
    at this link there is an article that speaks something about it.

    http://desnivel.com/expediciones/racetracker-explica-el-porque-de-l...

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