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Mismatch with GeoGraphics plotting of SHP data

Posted 8 days ago
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I'am trying to work with geographic city-data from Belgium Statistics Service. I can extract all the different elements from the SHP set. But I had great trouble to plot some some Geographic data. Some of the definitions for the geo tranformations are given below:


{"LambertConformalConic", "Centering" -> GeoPosition[{90., 4.36749}], 
"GridOrigin" -> {150000., 5.40009*10^6}, 
"StandardParallels" -> {51.1667, 49.8333}, 
"ReferenceModel" -> {Quantity[6.35691*10^6, "Meters"], 
Quantity[6.37839*10^6, "Meters"]}}

I used the geo data of the township of Aartselaar for these tets. The polygon coordinates are in the form of:

Polygon[{{151660.03130000085, 203013.60550000146},{.....

The polygon data must be transformed to adjust tot the coordinate system of the background maps.


But its difficult to find the all the meanings and syntaxes of the parameters to build a projection definition in GeoGridPosition. I tried to find a match between the elements of "Projection" (above) and

In[128]:= GeoProjectionData["LambertConicConformal"]

Out[128]= {"LambertConicConformal", {"Centering" -> {0, 0}, 
  "CentralScaleFactor" -> 1, "GridOrigin" -> {0, 0}, 
  "ReferenceModel" -> 1, "StandardParallels" -> {33, 45}}}

And merged those two in "projn2". This result in an error during an evaluation:

GeoGridPosition::invset: "ReferenceModel"->{6.35691*10^6m,6.37839*10^6m} is not a valid setting.

So I changed the definition of the ReferenceModel to "Bessl1841". I found this in an exemple with coordinates around Amsterdam. Resulting in below:

projb2 = {"LambertConformalConic", 
"Centering" -> GeoPosition[{90., 4.36748666666667}], 
"GridOrigin" -> {150000.013, 5.400088438*^6}, 
"StandardParallels" -> {51.1666672333333, 49.8333339}, 
"ReferenceModel" -> "Bessel1841"}

This works, but there is an offset between the polygons and the map (see att). I did a lot of trials on Belgium and Amsterdam data. I put everything together in SHP_4.nb. The output is deleted to limit the file length.


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