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I have a shapefile containing some sort of vectors or polygonal chains. This file is in the GCS_CH1903 geographic coordinate system (it is not specified though... if I import it into ArcMap it says Unknown). I want to project it to the GCS_WGS_1984 coordinate system and display it on a basemap(also in GCS_WGS_1984).
So I used Define Projection from the ArcToolbox on my imported layer and set it to GCS_WGS_1984. I think the projection is working, because the size of the lines seems correct, but there is no spatial reference so it was displayed somewhere west of Equatorial Guinea in the sea. I tried Create Spatial Reference but nothing happens if I select either GCS_WGS_1984 or GCS_CH1903.

Layer properties:

Projected Coordinate System:    WGS_1984_Web_Mercator_Auxiliary_Sphere
Projection: Mercator_Auxiliary_Sphere
False_Easting:  0.00000000
False_Northing: 0.00000000
Central_Meridian:   0.00000000
Standard_Parallel_1:    0.00000000
Auxiliary_Sphere_Type:  0.00000000
Linear Unit:    Meter

Geographic Coordinate System:   GCS_WGS_1984
Datum:  D_WGS_1984
Prime Meridian:     Greenwich
Angular Unit:   Degree

The information provided in this link is probably necessary but I have can't figure out where to enter it: http://www.swisstopo.admin.ch/internet/swisstopo/en/home/topics/survey/sys/refsys/swiss_grid.html

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I tried step 7 (because 1-5 seem irrelevant since i have a shape file). with input coordinate system: GCS_CH1903, output coordinate system GCS_WGS_1984 and geographic transformation: CH1903_To_WGS_1984_1 which results in the following error: invalid extent for output coordinate system –  rob Apr 17 '13 at 12:52
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1 Answer 1

up vote 5 down vote accepted

You need to use Define Projection and search for your original coordinate system. The one you are looking for can be found in:

Select >> Geographic Coordinate Systems >> Europe >> GCS_CH1903

Name: GCS_CH1903
Angular Unit: Degree (0.017453292519943299)
Prime Meridian: Greenwich (0.000000000000000000)
Datum: D_CH1903
Spheroid: Bessel_1841
Semimajor Axis: 6377397.155000000300000000
Semiminor Axis: 6356078.962818188600000000
Inverse Flattening: 299.152812799999990000

After you can use the tool Project tool (Projections and Transformations >> Feature >> Project), to change from the Swiss Geographic (GCS_CH1903) to WGS84

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I set the projection to GCS_CH1903 but I can't select my shape file in the Project Raster Tool. (Also the lines are not longer displayed) –  rob Apr 17 '13 at 12:27
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I gave you the wrong tool name, it's the "Project" tools(Projections and Transformations >> Feature >> Project) –  A.R Apr 17 '13 at 12:34
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