5 minute read
THE FUTURE OF MAPPING
Craig Feuerherdt and Neil Barr Bendigo Orienteers, Victoria
HAVE you ever stopped to consider why it costs so much to attend a major Orienteering carnival? The main reason is the time and effort put into creating the high quality Orienteering maps we have come to expect at such events.
It’s accepted practice to create new maps for Australian Championships and the Easter carnival. Cost of the maps is the major component of the entry fees. When mapping new terrain the cost is mainly mappers’ time. Consider a new map created by Bendigo Orienteers for the 2006 Middle-distance Championships. The terrain is previously unmapped, high quality granite. Only part is being mapped for the 2006 event, but we have a longer-term plan to map the complete area for an Australian Long-distance Championships. With the partial map almost complete, we can reasonably estimate the cost for completing the full map - about $12,000 give or take a square km or two.
It’s worth asking whether the Orienteering community can continue to justify making this scale of investment. Our club did some simple financial modelling and quickly came to the conclusion that we cannot repay an investment in professional mapping for anything less than a national carnival event. And we wonder whether we can justify the investment in a highly detailed (eg granite) map for future carnivals if participation continues to decline. Here are some thoughts on potential solutions to reducing the costs of maps.
If participation rates continue to fall, we will have to get used to fewer maps of virgin terrain and more remaps of existing Orienteering maps. The number of virgin areas close to major population centres is declining but there are still suitable areas remaining. In Victoria we know of half a dozen high quality granite areas that have not been mapped. We believe NSW has found at least that many in the Dubbo area alone. But do we need all of these areas mapped?
How many maps are needed?
Each State can expect to host Easter and a National Championships about every five years. Assume a cycle of 15 years map life (10 years of use and 5 of rest) then at a minimum we need 12 high quality maps in each State. If we include Middledistance Championships as a major event, the total rises to 15 maps. Allowing for contingencies such as fire might lead to a more realistic total of 20 maps. Once those 20 maps exist on OCAD, future remapping should be relatively cheap. By limiting our mapping to these 20 areas, the mapping component of the entry fee for major events should be reduced.
Orienteers being orienteers, our love of the novel will guarantee we won’t limit ourselves to this small portfolio of maps. We will keep looking to map new classic terrains. Then there are the mapping needs for Sprint and MTBO. With so much mapping to be done, can we simplify the process and thus minimise the costs?
GPS technology
Our new 4 square km granite map was made using traditional mapping techniques. Aerial photographs were given to Chris Wilmot for photogrammetric interpretation. He extracted contours and approximate vegetation boundaries, as well as visible rock for the whole map. The interpretation, completed by Alex Tarr, took four weeks of field-work, including a week for transcribing everything into OCAD.
Skilled interpretation by the human mapper will always be required for new maps however, there are technologies that can save time and make field-work easier. The obvious technology is the Global Positioning System (GPS). Like several clubs, Bendigo Orienteers has been experimenting with GPS. The conclusions we reached are mixed.
Using a standard GPS receiver (from any outdoor shop), the technology is of little use due to limited accuracy. Manufacturers only guarantee being within a maximum of 15 metres from the true grid reference. Our experience suggests this is an optimistic claim. The error can make a huge difference in the simple task of logging track networks. These receivers are capable of better accuracy, given the right conditions, however they should probably only be used for mapping tracks on Rogaine maps. The alternative is a GPS capable of correcting itself in real-time. We have mapped the tracks in virgin terrains using one of these (borrowed) devices and a bicycle. The GPS receiver is connected to a handheld computer (HP IPAQ) with tracking software, making it possible to visualise the output in real time. The results were accurate to within 30cm when we had full signal. The main shortcoming is signal drop-outs which occur when the vegetation canopy restricts the signal from the correction satellite. The thicker the canopy or the further south the location (i.e. Tasmania), the more likely drop-outs will be.
Data captured by GPS can be superimposed on a standard base map, vastly improving the base map. This technology suggests that standard Orienteering maps may be relatively accurate but absolutely inaccurate. When attempting to transform a standard Orienteering map into a real world coordinate system we found it to be 1:14,500 in one axis and 1:16,000 in another. So if we want to use GPS technology and the latest functionality provided in OCAD 9, we will need to rectify our existing maps to a standard topographic projection. It makes sense to use a base defined in real world coordinates when one starts photogrammetric interpretation or has other base data. This step may future-proof the mapping investment. These are some of the issues associated with attempting to incorporate GPS technology into data collection and field-work. It would help if real-time GPS became a lot cheaper ! The model we used is a little old now but cost close to $20,000, an investment not likely to be made by the Orienteering fraternity.
Portable computer and GPS unit.
Other technologies
Craig had the opportunity to attend the 22nd International Cartographic Association conference held in Coruna, Spain in July 2005. A whole session was dedicated to Orienteering mapping. Four speakers, all European, presented a range of topics. Of most interest was one by an Austrian who was involved in a trial exercise using LIDAR (Laser Identification Detection and Ranging) data to regenerate a small portion of an existing Orienteering map.
