[talk-au] [OSM-talk] city accuracy

Franc Carter franc.carter at gmail.com
Mon Sep 17 01:09:34 BST 2007


Hi,

I agree the city is reasonably complete, there are several small (tiny)
lanes missing,
especially around the eastern side. It's the accuracy that seems to be a bit
out in
some places, i.e streets not being parallel and such. So 'something' is out
because
the traces are bad it's difficult to decide which are the good ones and
hence fix it
become a consistent accure whole.

I was thinking of getting some more accurate points from GPS averaging and
then
working from them and the Yahoo Imagery.

If you have some accurate points, I think it would be great to put them in
to OSM
and label them in some way.

cheers

On 9/17/07, Ian Sergeant <isergean at hih.com.au> wrote:
>
> > I have had a look at a few places in Sydney on Yahoo Imagery with
> > josm and parts of it
> > are out by a fair bit - roads go at inconsistent angles which is the
> > giveaway. Obviously
> > getting good traces in amongst all those tall buildings is pretty
> unlikely.
>
> > So, does this seem reasonable and does anybody have a better way of
> getting
> > some known good points to work from ?
>
> Hi,
>
> 1. I think most of the CBD areas are fairly complete as far as the streets
> go.  There are lots of paths etc that are missing.  Do you notice any
> obvious holes?  You should be able to add missing bits by reference to the
> existing?
>
> 2. I have some points for street corners in the CBD.  I have points for
> Martin Place intersections, and many other street intersections which I
> have got with GPS surveying.  I've generally aligned streets with these
> points in the CBD, where I have them.
>
> 3. If there is a particular street corner you would like (within a
> lunchtime walk of the Quay) I'm happy to get a GPS ref of it for you to
> assist.  Street corners work best to avoid the canyoning between street
> corners in the city.  I can generally get better than 5m accuracy on the
> points, but not always.
>
> Ian.
>
>


-- 
Franc
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