On 20 July 2012 16:19, Steve Bennett <[email protected]> wrote:
> IMHO it would be very beneficial to have overseas armchair mappers in > whatever capacity they like. There are so many little roads around the > place - I'd much rather have them mapped, with some inaccuracies (eg, > access permissions wrong), than not mapped at all. > We're not going to agree on the survey vs aerial thing today. We haven't for the last however many years. My opinion is being routed down an impassable or non-existent road is an order of magnitude worse than being sent on a longer route due to a road being absent. I would, however, make the point to those willing to help, that from my initial scans there is so much to do that doesn't require any semblance of local knowledge. There are lots and lots of sections of coastline missing for starters. Hundreds of broken islands. Roads that are missing nodes travelling way off their path. Roads under lakes and waterways. Railway station names. Place names. Split ways. Roundabouts. Missing and incomplete waterways and lakes. I've hours already working on stuff that doesn't require any local knowledge, and I haven't made a tiny dent. Also, FWIW, the Bing imagery is generally great - I've certainly not > seen anything like a 100m discrepancy. Wherever I have a GPS trace, > it's always aligned very well with the Bing imagery. IMHO (possibly in > the minority) even mapping based on misaligned imagery isn't a major > problem. What's worse - a town that is perfectly mapped but 100m, or > the same town not mapped at all? > Generally so. But the much of the northern suburbs of Sydney is all cloud covered. Southern Highlands of NSW is misaligned by around 10-20m in parts. Northern Victoria is misaligned too around Beechworth and Wangaratta. Normal precautions for using imagery anywhere in the world apply. And with the AGRI data and existing GPS traces and objects, it should be quite possible to adjust, so hopefully 100m offset towns can be easily avoided! :-) Ian.
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