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Eckert III Projection

The Eckert III projection, developed by the German cartographer Max Eckert-Greiffendorff in 1906, is a pseudocylindrical equal-area projection. The main use is in thematic world maps.

Required Parameters

To convert Eckert III coordinates, the following parameters have to be set:

• False Northing;
• False Easting;
• Longitude Of Origin;

Eye4Software GPS Toolkit

The following code sample (VBScript) shows how to use the Eckert III Projection with the Eye4Software GPS Toolkit:

' demo_eckert3.vbs
'
' This demo translates lat/lon coordinates (WGS84) to Sphere Eckert III coordinates using
' Eckert III
'
' This demo specifies a map grid based on the Eckert III, 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 & " - Eckert III Projection Demo" 
WScript.Echo

' // Start of parameters part //

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

' Set Source Grid: Latitude/Longitude
objGridSrc.Projection		= objConstants.GPS_PROJECTION_NONE
objGridSrc.Datum		= objDatumSrc

' Set Destination Datum: Authalic Sphere (Spheroid)
objDatumDst.Axis		= 6371000.000
objDatumDst.Flattening		= 0.0

' Set destination grid: Eckert III Sphere
objGridDst.Projection		= objConstants.GPS_PROJECTION_ECKERTIII
objGridDst.Datum		= objDatumDst


' Set Source coordinates
objProjection.Latitude		=  36.5625
objProjection.Longitude		= -61.8750

' // End of parameters part //

' Perform the transformation
WScript.Echo "Convert from Latitude / Longitude to Sphere Eckert III using Eckert III 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
	WScript.Echo "Altitude    = " & objProjection.Altitude
End If

WScript.Echo "Ready."

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