[Talk-GB] OS VectorMap water feature import

[Craig Loftus]

> Have any large scale imports from this dataset already been done?

Unfortunately some have. Orkney is particularly bad.

> Do people think this is a good idea?  Any suggestions regarding the process?

I don't think area based importing is useful. Too many fragmented
waterways, and non-existent drains get pulled in. The few imports I've
done have focused on specific features, e.g., the banks and
tributaries of a river in an area I was mapping. It takes a long time
to get the sections connected together, the islands added, and all the
waterways connected; without focusing on a specific feature it would
be far too easy to overlook bits that needed tidying up.

In terms of the process, I found it useful to select and export just
the features I wanted in QGIS before extracting to OSM. And then to
use the JOSM validator to quickly eliminate the hundreds of duplicate
and unconnected nodes that seem to be created. Using exallpoly.py with
riverbanks tends to result in problems and I ended up modifying it to
not close the areas.

Craig

On 11 December 2011 11:26, Borbus <borbus at gmail.com> wrote:
> First of all, when I say import I mean a manual import: reprojection of
> OS shapefiles, conversion to OSM data and careful processing in JOSM
> before uploading.
>
> I'd really like to get all the water features from OS into OSM.  It's
> very useful data and also makes maps prettier.  It's quite a laborious
> task, though, as the data requires manual creation of multipolygons and
> of course merging with any water features we already have.
>
> I have already done a small amount here:
> http://www.openstreetmap.org/?lat=52.6006&lon=1.6362&zoom=13&layers=M
> Although I have not joined together all gaps, just some gaps where a way
> crosses it and it is obviously a conduit.
>
> Now I have split the Vectormap square TG into smaller chunks which I
> plan to process one by one and upload.  The amount of data in just this
> square is quite large, but it's still probably less than half of Norfolk.
>
> Have any large scale imports from this dataset already been done?
>
> Do people think this is a good idea?  Any suggestions regarding the process?
>
> Happy mapping,
>
> Borbus.
>
> _______________________________________________
> Talk-GB mailing list
> Talk-GB at openstreetmap.org
> http://lists.openstreetmap.org/listinfo/talk-gb