Eye4Software Hydromagic

Professional hydrographic survey software


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Introduction

A map datum is a reference from which measurements are made. In geodesy, a geodetic or map datum is a set of reference points on the earth's surface against which position measurements are made, and (often) an associated model of the shape of the earth (reference ellipsoid) to define a geographic coordinate system. Some examples of geodetic datums are: NAD27, NAD83, ED50 etc...


Parameters

An map datum can be defined in the Eye4Software Coordinate Calculator or Eye4Software GPS Toolkit using 7 parameters, also called Helmert-7 parameters:

Also an ellipsoid has to be specified when a map datum is defined.


Map Datum EPSG#4041 - Unknown datum based upon the Average Terrestrial System 1977 ellipsoid



Datum Transformation Parameters Unknown datum based upon the Average Terrestrial System 1977 ellipsoid (to WGS84 datum)

Parameter Value
EPSG # 4041
Map Datum Name Unknown datum based upon the Average Terrestrial System 1977 ellipsoid
Ellipsoid Name Average Terrestrial System 1977
Conversion None


Ellipsoid Parameters ( Average Terrestrial System 1977 Ellipsoid )

Parameter Value
Semi Major Axis 6378135
Inverse Flatenning 298.257


Back to index of all map datums...