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I use a GPS Messenger Device which transmits my location to family / friends every ten minutes via the Satellite Phone network. In addition to an SOS / 911 button it has a "Help Me" button which asks a nominated person to come and pick me up because although my life is not in danger I'm unable to get home under my own power. This is all well and good if I'm on a road. But if I'm in a forest or national park, I could be miles away from a road. So someone wanting to help me, who might not be familiar with mapping tools, might not know how to get to the nearest road to my last reported location. Is there some tool that I could use (or build upon) which, given an off-road location, could return a near-by on-road location? It would be even better if it was able to work out if there was a near by track / fire-road / trail. I'm a software developer, and don't mind doing a lot of the hard yards myself. I just need some hints about where to start. Thanks in advance. Neil |
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Almost all routing software will, when given an arbitrary starting position, will find the nearest road/track that it can route on. For example, here is a route starting in the middle of the mountains using MapQuest's OSM routing. http://open.mapquest.co.uk/link/10-AmJUgP94 You can see that although point A is nowhere near the road, it has figured out which is the nearest road to start from. Similar results happen with other routing systems, and so you could find one / set one up to use OSM data for pedestrians, and then it will find the nearest trail / path to your location. The routing software gosmore does it too and sourcecode is available at http://svn.openstreetmap.org/applications/rendering/gosmore/
(23 Feb '11, 09:35)
petschge
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