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Oblique Stereographic Projection

The stereographic projection, in geometry, is a particular mapping (function) that projects a sphere onto a plane. The projection is defined on the entire sphere, except at one point — the projection point. Where it is defined, the mapping is smooth and bijective. It is conformal, meaning that it preserves angles. It is neither isometric nor area-preserving: that is, it preserves neither distances nor the areas of figures.

Required Parameters

To convert Oblique Stereographic coordinates, the following parameters have to be set:

• False Northing;
• False Easting;
• Latitude Of Origin;
• Central Meridian;
• Scale Factor.

Eye4Software GPS Toolkit

The following code sample (VBScript) shows how to use the Oblique Stereographic Projection from the Eye4Software GPS Toolkit:

' demo_stereographic.vbs
'
' This demo translates lat/lon coordinates (WGS84) to RDNAP coordinates (Amersfoort) using
' stereographic projection
'
' This demo specifies a map grid based on the Stereographic projection, by setting all geodetic parameters. 
'
' If you want to convert using one of the 4000 grids that are included in the component,
' you should have a look at the demo_gridsimple.vbs demo (recommended for users with less or no experience in geodesy).

Option Explicit

Dim objDatumSrc, objDatumDst, objGridSrc, objGridDst, objProjection, objConstants

Set objDatumSrc		= CreateObject ( "Eye4Software.GpsDatumParameters" )
Set objDatumDst		= CreateObject ( "Eye4Software.GpsDatumParameters" )
Set objGridSrc 		= CreateObject ( "Eye4Software.GpsGridParameters" )
Set objGridDst 		= CreateObject ( "Eye4Software.GpsGridParameters" )
Set objProjection   	= CreateObject ( "Eye4Software.GpsProjection" )
Set objConstants 	= CreateObject ( "Eye4Software.GpsConstants" )

WScript.Echo "Eye4Software GPS Toolkit " & objProjection.Version & " - Stereographic Projection Demo" 
WScript.Echo

' // Start of parameters part //

' Set Source Datum: WGS84
objDatumSrc.Axis		= 6378137.000
objDatumSrc.Flattening		= 298.257223563

' Set Source GridL: Latitude/Longitude
objGridSrc.Projection		= 0
objGridSrc.Datum		= objDatumSrc

' Set destination datum: Amersfoort
objDatumDst.Axis 		= 6377397.155
objDatumDst.Flattening  	= 299.1528183
objDatumDst.TranslationX	= 539.16
objDatumDst.TranslationY	=  26.15
objDatumDst.TranslationZ	= 465.89
objDatumDst.RotationX		= -1.304
objDatumDst.RotationY		= -0.103
objDatumDst.RotationZ		= -1.145
objDatumDst.ScaleFactor		= 4.0772

' Set destination grid: RDNAP
objGridDst.Projection		= objConstants.GPS_PROJECTION_STEREOGRAPHIC
objGridDst.Datum		= objDatumDst
objGridDst.FalseNorthing	= 463000.00
objGridDst.FalseEasting		= 155000.00
objGridDst.OriginLatitude	= 52.156161
objGridDst.OriginLongitude	=  5.387639
objGridDst.ScaleFactor		=  0.999908

' Set Source coordinates
objProjection.Latitude		= 51.900000
objProjection.Longitude		=  4.400000

' // End of parameters part //

' Perform the transformation
WScript.Echo "Convert from Latitude / Longitude to RDNAP using stereographic projection"
WScript.Echo
WScript.Echo "Latitude    = " & objProjection.Latitude
WScript.Echo "Longitude   = " & objProjection.Longitude
WScript.Echo

objProjection.TransformGrid objGridSrc, objGridDst

' Return the result
WScript.Echo "Result: " & objProjection.LastError & " (" & objProjection.LastErrorDescription & ")"
WScript.Echo
If ( objProjection.LastError = 0 ) Then
	WScript.Echo "Northing    = " & objProjection.Northing
	WScript.Echo "Easting     = " & objProjection.Easting
End If

WScript.Echo "Ready."

Click here to show a list of all supported map projections.