[Talk-GB] building shapes from OS Street View

Graham Jones grahamjones139 at googlemail.com
Mon Apr 5 18:41:11 BST 2010

I think this is a really good idea, and is one of the main benefits of the
StreetView data.

I have been wondering how to do this, but haven't got far.

I would like to see a plugin for josm that takes a raster input (landsat,
yahoo, StreetView) and processes it into 'draft' ways around areas of
constant(ish) colour - the user then tidies it up and tags it before
uploading (ie I would be very wary of a 'blind' import!).   I think
streetview would be the easiest because of the high contrast - I would like
to see it work for landsat because I am colourblind and can't trace the
outline of woods, and the North Yorkshire moors need some more detail!.

Someone (I think it was Mike DuPont) reported doing this with gdal_contour,
but I haven't tried it yet, and I haven't looked at how to turn this into a
josm plugin.

If I'd thought of it earlier I would have suggested this as a GSoC student



On 5 April 2010 17:57, TimSC <mapping at sheerman-chase.org.uk> wrote:

> Hi all,
> I was looking at the available OS data and one of the things they have
> but is not really in the current OSM database is building shapes.
> Individual buildings appear in the Street View data. The VectorMap
> District data seems to focus on land use and only has "important"
> buildings. The Street View data is much more complete in terms of
> individual buildings. I guess the questions we have to address are: "is
> this data worth having in OSM?" and "are there any better sources of
> building outline?" I think it would be a valuable addition for highly
> detailed mapping of urban areas, campuses, etc.
> The other sources of building outlines I know of are the 1st edition OS
> sheets (which are rather old), Yahoo imagery (which takes work to
> trace), and manual surveying (which is a major hassle since buildings
> tend to throw off GPS positions). Another source would be preferable to
> these.
> If we do want this data, it seems to be only available as a raster
> layer. (Does anyone know if this will be available as a vector layer?)
> Converting raster map data to vector data is non trivial but I think it
> is achievable. The building colour in the raster map seems to be unique.
> The raster maps could be selected by colour, vectorised and simplified
> (to remove redundant nodes). Since we have a significant number of
> buildings mapped in the UK, we could presume that we don't want to
> overwrite or duplicate what is already there. Buildings could be
> imported if it would not overlap with an existing building in OSM. One
> problem is some buildings are marked as leisure=stadium without a
> building=*. We might end up with duplicates of stadiums, leisure
> centres, churches and so on. Would we want the import to be more
> cautious to prevent this? I won't be importing anything until the
> rectification of Street View is complete (and I get a feel for the
> consensus on the mailing list) but I have demoed most of the method in
> python using the shapely module to do some geometry transforms.
> Any general thoughts on buildings and imports? Will this data be
> officially available in vector form at some point?
> We don't seem to have much comment on the legal issues and the
> implications of ODbL yet. Do we have a view as to if our attribution is
> sufficient?
> Regards,
> TimSC
> _______________________________________________
> Talk-GB mailing list
> Talk-GB at openstreetmap.org
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Dr. Graham Jones
Hartlepool, UK
email: grahamjones139 at gmail.com
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