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I have a shp polygon in GGRS87/Greek Grid. I want to display the polygons on googleearth. I use "layer to kml" tool in ArcMap. However when I open the kml in googleearth the polygons are not aligned correctly (they are all moved southwest from their right position).

Has to do with the transformation of datums?

Notes: 1) in the tool I clicked on environments and as coordinate system I chose GCS_WGS_1984 and for transformation: GGRS_1987_To_WGS_1984 2) before applying the layer to kml tool, I tried to use Project tool to change the coordinate system to WGS84. But for an unknown reason I didn't have the option to use geogr. tranformation

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    did you use ArcMap for the projection? – Moh Feb 16 '18 at 13:34
  • while not a direct answer this page may help you rmseifried.wordpress.com/2013/01/09/… – user92055 Feb 16 '18 at 16:40
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    If you're not getting a geographic transformation, try redefining the data's coordinate system to the Esri GGRS87/Greek Grid version. There may be a difference in the GGRS87 definition that's making it not equal the one in the transformation. – mkennedy Feb 16 '18 at 19:08
  • What GIS software are you using? – PolyGeo Feb 16 '18 at 20:54
  • You might want to look in the Source tab under your layer properties, to see if the Reference System was assigned with the Esri-recognized WKID code. If not, you might want to run the GP "Define Projection", as GGRS87, and then proceed to Project and then Conversion. – AlecZ Feb 16 '18 at 23:09
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Use WEB Mercator it would work.

  • Before converting the shp to kml, I first used the Project tool and as output coord. system I selected "WGS_1984_Web_Mercator_Auxiliary_Sphere" (from Proj. C.S\World) and used the GGRS_1987_To_WGS_1984 transformation. Unfortunately, the kml produced in the next step has the same false alignment (shifted southwest) – cartographer67 Feb 19 '18 at 7:15
  • Can you share some sample data so that i can reproduce the problem and check it. – Sandeep Kumar Feb 20 '18 at 7:55
  • Data: we.tl/uX9caVwXUl I am still trying but nothing yet. And here is a paradox: When I open the data with QGIS and save them as kml (I select WGS84, EPSG4326 as CRS) the polygons are correctly sited in google earth. BUT if I make any analysis in ArcMap 10.4 (eg I selected some of the poylgons and extracted them as a new shapefile) then when I follow the same procedure in QGIS the polygons of the new kml are misaligned as did in the ArcMap! – cartographer67 Feb 21 '18 at 9:54
  • And here is the kml with the correctly aligned polygons: we.tl/BhjiUcyp7f – cartographer67 Feb 21 '18 at 10:00
  • what is your default workspace in arcmap check it once – Sandeep Kumar Feb 21 '18 at 10:45

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