Topographic coverage of Australia as offered by Garmin Topo Australia & New Zealand V5 maps for Garmin GPS units is grossly inaccurate. This is of concern because of the possibility of serious harm befalling people who are reliant on the accuracy of the product.
As evidence of inaccuracy, I offer a selection of photographs taken of the screen of a Garmin Montana 680t GPS unit that was loaded with the above Garmin product. The photographs show Garmin’s depiction of the topography of the Wollemi National Park (some 100 kilometres north west of Sydney). Examples are from three locations; one on each of the Capertee (56H KJ599282), Wolgan (56H KJ 593208) and Colo River Gorges (56H KJ707213) (WGS84). Adjacent to each Garmin map depiction is another photograph of the same location taken from first edition 1:25000 NSW topographic maps (1977) produced by the Land Information Centre New South Wales. These later maps conform in accuracy to National Mapping Council standards.
The Garmin product depicts numerous non-existent ridges bridging the gorges down which each of the rivers flow. The examples I have chosen show the Capertee river climbing 310 metres, the Wolgan 200 metres and the Colo 170 metres to cross such ridges.
Without either visiting these locations or comparing the photographs derived from the paper maps of the same locations, the Garmin product’s lack of real detail (as distinct from fabricated detail) isn’t immediately apparent. The Garmin depictions contain meaningless, mostly evenly spaced, 10-metre interval contours to fill the voids between real or imagined high and low points. Consequently, Garmin fails to depict cliffs that are several hundreds of metres in height, showing them instead as steep slopes. All true detail is lost.
Similar – though less spectacular – mapping errors are to be seen in the Garmin coverage of the West MacDonnell Range (near Alice Springs) where rivers and streams are also shown as running across imaginary saddles. Another worrisome example is to be found in the newly incorporated map of Lord Howe Island, where a non-existent road is shown to scale the grossly inaccurately mapped heights of Mount Gower before plunging over a cliff!
Disappointingly there appeared to be errors in every Garmin map section I have viewed. Almost everywhere are examples of water flows that defy gravity!
I speculate that Garmin obtains spot heights for each area covered then uses an algorithm to draw in the contours. Clearly there is no checking of the result by a cartographer and no quality control. But high quality Australian topographic information and maps have been available for many decades. Why hasn’t Garmin used published topographic information as the basis for their product? Is it unavailable to them, impossible to digitise or is it something to do with profit?
Currently, Australia lacks legislative support for an enforceable standard to which GPS maps must conform. I believe this shortcoming needs to be addressed as the public deserves better than this.
Garmin should either withdraw their defective products from the market or affix obvious warning labels that clearly describe their low level of accuracy and emphasise that they must never be relied upon. Purchasers need to be advised on the need to carry appropriately accredited topographic maps in addition to a GPS that is loaded with their product.
Wild is continuing to investigate this matter and hopes to have a response from Garmin on the matter in the coming days. If anyone has been affected by the issues raised in this article, please write to us at firstname.lastname@example.org.