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I'm reading a Shapefile containing polygons representing certain areas in my neighborhood. For this I use C# and a library called DotSpatial.

I can iterate the so called Features in the Shapefile and each feature has Coordinates with a X and Y property value. They look like this:

[124060,375000004, 487043,270000004]
[124068,295000004, 486998,390000004]
[124071,430000004, 486891,470000004]
[124010,435000004, 486694,295000004]

I need latitude/longitude values so after some reading I found that I needed to reproject the coordinates, either with/without projecting file (see answer: here).

My goal is to get values in the area of Amsterdam (which is what the Shapefile contains): [52.4,4.9]

This is possible by calling (if projection file is included):

file.Reproject(DotSpatial.Projections.KnownCoordinateSystems.Geographic.World.WGS1984);

Resulting in:

[-37,9115551003779, 23,9336542782764]
[-37,9117191600094, 23,9331853015717]
[-37,9123377534534, 23,9321317059377]
[-37,9144451002488, 23,9304589279205]
[-37,9153029784154, 23,9298198785957]

This looks promising, but nowhere near [52.4,4.9]

Or (without projection file):

file.Projection = DotSpatial.Projections.KnownCoordinateSystems.Projected.UtmWgs1984.WGS1984UTMZone32N; file.Reproject(DotSpatial.Projections.KnownCoordinateSystems.Geographic.World.WGS1984);

Resulting in:

[5,61357508612624, 4,39863081202557]
[5,61364817701951, 4,39822583083791]
[5,61368074834023, 4,39726037781928]
[5,61314000884886, 4,39547721608089]
[5,61290560849057, 4,39478423443173]

But both are not the results what I was hoping for. I am in no way any geometry expert and I understand about spheres and cylinders etc. but I'm really unable to figure out how to get my coordinates in lat/long format. Is this possible?

The .prj file looks like this:

PROJCS["RD_New",GEOGCS["GCS_Amersfoort",DATUM["D_Amersfoort",SPHEROID["Bessel_1841",6377397.155,299.1528128]],PRIMEM["Greenwich",0],UNIT["Degree",0.0174532925199432955]],PROJECTION["Double_Stereographic"],PARAMETER["False_Easting",155000],PARAMETER["False_Northing",463000],PARAMETER["Central_Meridian",5.38763888888889],PARAMETER["Scale_Factor",0.9999079],PARAMETER["Latitude_Of_Origin",52.15616055555555],UNIT["Meter",1]]

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    Add the contents of the .prj file to your question. It is plain text. – user30184 Feb 13 '15 at 14:11
  • Ok did that, I can see some relevant data there. But I have no idea on how to interpret this... – Ropstah Feb 13 '15 at 14:57
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    Interpret it so that your data are in EPSG:28992 spatialreference.org/ref/epsg/28992 – user30184 Feb 13 '15 at 15:10
  • Ah that works. Seems to be named KnownCoordinateSystems.Geographic.Europe.Amersfoort. Is it very strange that I can't make sense out of all this? :). Thanks a lot! – Ropstah Feb 13 '15 at 15:30
  • I got the same problem with Amersfoort EPSG:28992. My shape files are not placed in exact location (Amsterdam). Can you help me? – Shilpakar Amar Jun 13 '17 at 9:55

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