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GEOD software

GEOD is a FREE download, only available for Microsoft Windows 95/98/2000, NT and XP.

The program was developed by Graham Samuel and Associates in conjunction with the Department of Lands and the University of Newcastle (Surveying). The Australian Surveying and Land Information Group (AUSLIG) financially assisted the program development.

GEOD is a universal software package, which converts or transforms between various coordinates currently in use in Australia: AMG/AGD66/84, ISG66, MGA/GDA94 and Cartesian XYZ 66/84/94. In addition, Grid Convergence and Point Scale Factor are calculated.

The available transformation options are compatible with the GDA Technical Manual and include:

  • a 'High Accuracy' method, using NTv2 Grid Interpolation (a methodology developed by GSD - Geomatics Canada). The NTv2 ASCII files use Canadian format.

Suitable for most purposes (eg when observations are unavailable for readjustment).

Absolute accuracy: ~ 0.1m (95%) (except in/near Barham, NSW and Koondrook, Victoria, where the accuracy is 0.25m and 0.45m, respectively).

Relative accuracy: similar to source.

Caution: Individual State grids have been integrated into one national distortion grid.

  • a 'Medium Accuracy' method, using the 7 parameter similarity transformation calculation.

Suitable for GIS data, derived from maps, for calculation of cartesian coordinates or when the Grid method can not be used.

Absolute accuracy: ~ 1m (95%).

Relative accuracy: same as source (over limited area).

Values of the National and regional 7 parameters are displayed and can be copied for use in other transformation packages.

User's comments and suggestions are most welcome and will be considered for incorporation in the next version of GEOD. Please contact Graham Samuel E: graham.f.samuel@bigpond.com

Downloading the GEOD Program

Step 1

Download GEOD ver 3.42 software (ZIP 333 KB). You should save this zip file in an appropriate place on your system and then expand it. You can then run the program geod.exe.

Step 2

To use the High Accuracy transformations you will need to use the National or Regional Grid file covering your State or area. This file needs to be copied into a folder named DATA, established in the directory where you placed the GEOD program. The files relevant to NSW can be downloaded here:

The National grid file can be used for transformations anywhere in Australia.

The Grid files for other states can be downloaded from the web sites of the relevent jurisdictions. Some states also have sub grids which may be required for certain areas, and users should check for the existence of sub grids with those jurisdictions.

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