GEOD does not provide support for GDA94 – GDA2020 transformations.
Please enquire with your software provider for GDA2020 support and /or review the ICSM GDA2020 transformation products and tools website.
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 – now Geoscience Australia) 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 GDA94 Technical Manual and include:
Option 1: '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 (e.g. when observations are unavailable for readjustment).
- Absolute accuracy: ~ 0.1 m (95%) (except in/near Barham, NSW and Koondrook, Victoria, where the accuracy is 0.25 m and 0.45 m, respectively).
- Relative accuracy: similar to source.
- Caution: Individual State grids have been integrated into one national distortion grid.
Option 2: '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 cannot be used.
- Absolute accuracy: ~ 1 m (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 via firstname.lastname@example.org.
Downloading the GEOD Program
Download GEOD v. 3.42 software (PDF 332.6 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.
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 grid files can be downloaded from ICSM via the Transformation Grids page. Relevant to NSW are the following files:
- National Grid file (PDF 3.3 MB)
- South-East Australia - NSW and Victoria file (PDF 2.2 MB)
The national grid file can be used for transformations anywhere in Australia.
The grid files for other states may be downloaded from the websites 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.