[Talk-GB] building shapes from OS Street View

[Gregory]

On 24 May 2010 14:43, Richard Fairhurst <richard at systemed.net> wrote:

>
> I don't know what the quality of StreetView is like in your area, but I
> would weep if someone were to blindly trace from StreetView in Charlbury
> without ever having visited it. The building outlines just aren't that
> great. Let's not lose sight of OSM's strengths in an enthusiasm to slurp as
> much free data as possible.


If someone traces Hampton or Durham buildings with no intention of
on-the-ground surveying then I too will -well I won't cry, but I'll say some
angry words in the irc #osm channel. I'm getting annoyed enough at having to
fix over-keen landuse. It's not about the accuracy of the imagery(aerial or
OS) but about knowing the area, and finding out when a building might
need splitting with a gap or when they no longer exist due to recent
redevelopment.

Harry has done some good blog posts about London's gaps in buildings. But
this is an area with strong mapping activity. We can leave it to locals to
trace buildings in the gaps with some memory or to hold off if they know
people are surveying it this week. (Plug if your in the area, come to
http://wiki.openstreetmap.org/wiki/London/Summer_2010_mapping_parties ). In
cities & towns with no buildings at all, it's better to leave these blank
and when the mappers come they can work on it.

I know I don't like armchair mappers (or rather I don't want to be one).
There is a difference between tracing roads without names (helpful to route
between mapped cities or to the next unmapped place) and mapping every
unknown building (most information can be added to a node if the building
isn't there, even without a GPS people can survey and add this information
themselves).

I have been thinking about these people who like sitting at a hot computer.
Now I am doing house numbers/names it could be helpful to have someone trace
building outlines for me so that I have more free time to go outside and get
the information to add to and correct the details. I've briefly asked in irc
(and had no takers), but when I have I included details of where to not go
beyond, because I know some areas could easily be confused as to what they
are without local knowledge. This is the case for OS StreetView, and the
Surrey Aerial Imagery (still confused on the latter license). It might be
nice to have somewhere to request help from 'armchair mappers' this could
also be good for the crisis requests.

-- 
Gregory
osm at livingwithdragons.com
http://www.livingwithdragons.com
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