[talk-au] Redaction progress
inas66+osm at gmail.com
Fri Jul 20 09:17:29 BST 2012
On 20 July 2012 16:19, Steve Bennett <stevagewp at gmail.com> 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! :-)
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