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4 Replies to “Simple way for converting "Rijksdriehoek" coordinates to lat and long (WGS84) in C#”

1. Dank je voor deze code.
   Heb je ook zoiets voor het omgekeerde: LatLong naar Rijksdriehoek?

   M.vr.gr.,
   Jan Pieter

2. Op basis van http://sourceforge.net/projects/rd-wgs8

   public static double[] ConvertToRijksdriehoek(double wgs84_lattitude, double wgs84_longitude)
   {
   // The city “Amsterfoort” is used as reference “Rijksdriehoek” coordinate.
   int referenceRdX = 155000;
   int referenceRdY = 463000;

   // The city “Amsterfoort” is used as reference “WGS84” coordinate.
   double referenceWgs84X = 52.15517;
   double referenceWgs84Y = 5.387206;

   var Rpq = new double[4, 5];

   Rpq[0, 1] = 190094.945;
   Rpq[1, 1] = -11832.228;
   Rpq[2, 1] = -114.221;
   Rpq[0, 3] = -32.391;
   Rpq[1, 0] = -0.705;
   Rpq[3, 1] = -2.340;
   Rpq[0, 2] = -0.008;
   Rpq[1, 3] = -0.608;
   Rpq[2, 3] = 0.148;

   var Spq = new double[4, 5];
   Spq[0, 1] = 0.433;
   Spq[0, 2] = 3638.893;
   Spq[0, 4] = 0.092;
   Spq[1, 0] = 309056.544;
   Spq[2, 0] = 73.077;
   Spq[1, 2] = -157.984;
   Spq[3, 0] = 59.788;
   Spq[2, 2] = -6.439;
   Spq[1, 1] = -0.032;
   Spq[1, 4] = -0.054;

   var d_lattitude = (0.36 * (wgs84_lattitude – referenceWgs84X));
   var d_longitude = (0.36 * (wgs84_longitude – referenceWgs84Y));

   double calc_latt = 0;
   double calc_long = 0;

   for (int p = 0; p < 4; p++)
   {
   for (int q = 0; q < 5; q++)
   {
   calc_latt += Rpq[p, q] * Math.Pow(d_lattitude, p) * Math.Pow(d_longitude, q);
   calc_long += Spq[p, q] * Math.Pow(d_lattitude, p) * Math.Pow(d_longitude, q);
   }
   }

   var rd_x_coordinate = (referenceRdX + calc_latt);
   var rd_y_coordinate = (referenceRdY + calc_long);

   return new[] { rd_x_coordinate, rd_y_coordinate };
   }

3. Beste Roel,

   De tweede functie zou ik graag in VB.NET gebruiken, maar krijg in diverse conversie tools een foutmelding op Public Static Double[]

   Enig idee hoe ik dit in VB.NET voor elkaar kan krijgen?

4. Ha Roel,
   Beter laat dan ooit, bijgaand mijn T-SQL versie (SQL Server) van bovenstaande RD to Lat Long.

   voorbeeld aanroep: select latitude,longitude from ConvertRD_To_LatLong(122202,487250)

   go
   create function ConvertRD_To_LatLong (@x as float, @y as float)
   RETURNS @tblLatLong TABLE
   (latitude float NOT NULL,
   longitude float NOT NULL)

   AS
   BEGIN

   –select latitude,longitude from ConvertRD_To_LatLong(122202,487250)
   –latitude longitude
   –52.372143838117 4.90559760435224

   — Input
   — x = 122202
   — y = 487250
   — latlong
   — “52.372143838117, 4.90559760435224”

   declare @latlong varchar(20)

   — The city “Amsterfoort” is used as reference “Rijksdriehoek” coordinate.
   declare @referenceRdX int = 155000
   declare @referenceRdY int = 463000
   declare @dX float
   declare @dY float

   set @dX = (@x – @referenceRdX) * power(cast(10 as float), -5)
   set @dY = (@y – @referenceRdY) * power(cast(10 as float), -5)
   — nort/east recalc
   declare @sumN float = (3235.65389 * @dY)
   + (-32.58297 * power(cast(@dX as float), 2))
   + (-0.2475 * power(cast(@dY as float), 2))
   + (-0.84978 * power(cast(@dX as float),2) * @dY )
   + (-0.0655 * power(cast(@dY as float), 3))
   + (-0.01709 * power(cast(@dX as float),2) * power(cast(@dY as float), 2))
   + (-0.00738 * @dX) + (0.0053 * power(cast(@dX as float), 4))
   + (-0.00039 * power(cast(@dX as float), 2) * power(cast(@dY as float), 3))
   + (0.00033 * power(cast(@dX as float), 4) * @dY)
   + (-0.00012 * @dX * @dY)

   declare @sumE float = (5260.52916 * @dX)
   + (105.94684 * @dX * @dY)
   + (2.45656 * @dX * power(cast(@dY as float),2))
   + (-0.81885 * power(cast(@dX as float),3))
   + (0.05594 * @dX * power(cast(@dY as float),3))
   + (-0.05607 * power(cast(@dX as float),3) * @dY)
   + (0.01199 * @dY)
   + (-0.00256 * power(cast(@dX as float),3) * power(cast(@dY as float),2))
   + (0.00128 * @dX * power(cast(@dY as float),4))
   + (0.00022 * power(cast(@dY as float),2))
   + (-0.00022 * power(cast(@dX as float),2) )
   + (0.00026 * power(cast(@dX as float),5))

   — The city “Amsterfoort” is used as reference “WGS84” coordinate.
   declare @referenceWgs84X float = 52.15517
   declare @referenceWgs84Y float = 5.387206
   — calculate to degrees
   declare @latitude float = @referenceWgs84X + (@sumN / 3600.0);
   declare @longitude float = @referenceWgs84Y + (@sumE / 3600.0);

   –set @latlong = cast(@latitude as char(10)) + ‘,’ + cast(@longitude as char(10))
   insert @tblLatLong SELECT @latitude,@longitude;

   return;
   END

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