[HOT] PHL: making use of building damage data

[Andrew Buck]

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Nick, see my responses inline below:

> 1. Having referred to the OSM Damaged buildings crisis mapping 
> <http://wiki.openstreetmap.org/wiki/Damaged_buildings_crisis_mapping>
> page, I'm not sure I'm making the best use of the data that's
> there, e.g. how to access typhoon:reviewed and typhoon:damage ?
> Would we be better not using shapefile downloads but another format
> that preserves more of the source data structure?

Have a look at the last column in the shapefiles which should be
called 'tags'.  In that you will find all the other tags that are not
part of the other columns so you can query against that for
typhoon:reviewed=* and so forth.

> 2. Perhaps it's just the way that the shapefile attributes are
> derived from the source OSM data, but how could we separate the
> building type (house, office etc) from the damage status?

Using the current tagging shceme we really cant since a damaged church
for example would need building=damaged and building=church at the
same time which isn't allowed.  This is a known problem with this
scheme and it will likely be fixed after the public is mostly done
mapping, we will just go through and change the tags accordingly to
the new schema.

> 3. Finally (and apologies for touching on what I expect is a
> long-running question), how are such data time-stamped? I'm
> thinking for example of buildings that were already tagged as
> damaged pre-typhoon, or that become repaired.

We have the time stamps for when the objects were added to the DB
and/or tagged as damaged so in theory you can work out what disaster
everything relates to.  In practice though we also plan to work out a
better scheme for tagging this explicitely in the coming weeks/months
after the disaster response has settled down a bit.  Right now we are
just running with the current scheme since a lot of people are already
using it, we don't want to pull the rug out from under them during the
response, even if we know our current schema is sub-optimal and will
be changed in the future.

Hope this addresses your questions.

- -AndrewBuck

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