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Lambert Azimuthal Equal Area Projection

The Lambert azimuthal equal-area projection is a map projection used in cartography. It accurately represents area in all regions of the sphere, but it does not accurately represent angles. The Lambert azimuthal equal-area projection is used for navigation, thematic and USGS maps.

Azimuthal equal-area projections are able to present the whole Earth in a single map and with constant radial scale (distances increase linearly from the center of projection). Like the superficially similar azimuthal equidistant, the Lambert azimuthal projection strongly distorts shapes in the boundary of a worldwide map. However, the radial scale is not constant: in the polar aspect, parallels (circles of latitude) get closer together towards the border, just enough to preserve areas.

Required Parameters

To convert Lambert Azimuthal Equal Area coordinates, the following parameters have to be set:

• False Northing;
• False Easting;
• Latitude Of Center;
• Longitude Of Center;

Eye4Software GPS Toolkit

The following code sample (VBScript) shows how to use the Lambert Azimuthal Equal Area Projection from the Eye4Software GPS Toolkit:

' demo_lambert_aea.vbs
'
' This demo translates lat/lon coordinates (WGS84) to ETRS-LAEA using
' Lambert Azimuthal Equal Area projection
'
' This demo specifies a map grid based on the Lambert Azimuthal Equal Area 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 & " - Lambert Azimuthal Equal Area Projection Demo" 
WScript.Echo

' // Start of parameters part //

' Set Source Datum: WGS84
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: ETRS89
objDatumDst.Axis		= 6378137.0
objDatumDst.Flattening		= 298.257222101

' Set destination grid: ETRS-LAEA
objGridDst.Projection		= objConstants.GPS_PROJECTION_LAMBERTAEA
objGridDst.Datum		= objDatumDst
objGridDst.OriginLatitude	= 52.0
objGridDst.OriginLongitude	= 10.0
objGridDst.FalseNorthing	= 3210000.0
objGridDst.FalseEasting		= 4321000.0

' Set Source coordinates
objProjection.Latitude		= 52.775
objProjection.Longitude		= 10.440

' // End of parameters part //

' Perform the transformation
WScript.Echo "Convert from Latitude / Longitude to ETRS-LAEA Grid using Lambert Azimuthal Equal Area 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.