[talk-au] Update on NearMap wiki page

Peter Ross peter at emailross.com
Mon Nov 30 22:13:01 GMT 2009

On Tue, Dec 1, 2009 at 3:02 AM, Steve Bennett <stevagewp at gmail.com> wrote:
> On Tue, Dec 1, 2009 at 2:43 AM, John Smith <deltafoxtrot256 at gmail.com>
> wrote:
>> Someone left a note about the NearMap imagery should be aligned with
>> existing ways, but in a lot of cases the opposite is true, most of the
>> ways that don't line up that I've seen are inaccurate.
>> Even with the poorly aligned Melbourne imagery Ross was still saying
>> the imagery was at most only 6m out, which is on par with most
>> consumer grade GPS devices.
> I think you're referring to the note I left. What I wanted to get across is
> that newbies (like me, last week :)) should not go around updating
> realigning existing roads without talking to someone first, or thinking it
> through.
> Do we have an official strategy? In St Kilda, there's a fairly big
> discrepancy between existing data and the images, and I haven't really known
> what to do about it. The bike path in particular was so far off that I
> really no choice but to move it, because it was going through buildings...
I've been checking the nearmap imagery against locations on the map
where I have multiple traces for a road/path.  I've found the imagery
to be within 1m.

So if there are not a lot of gps traces for a road/path then I realign
the path to the nearmap imagery.  If there are a lot of traces and the
path is consistent with those traces but not the imagery I leave it as
is and report the misalignment to the nearmap people (only done once).

I believe they find error reports like this very useful to keep
improving the alignment of their imagery.

Also as an aside the first imagery for melbourne was out by the 6m.
It has since been realigned to within 1m.  The second set is perfect
as far as I can tell.


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