[HOT] PHL: making use of building damage data

[Nick McWilliam (MapAction)]

Hi Andrew -
Much appreciate the quick response - will check the tag attribute; and
understand your comments about the design of the tagging scheme.
Best wishes -
Nick.

-----Original Message-----
From: Andrew Buck [mailto:andrew.r.buck at gmail.com] 
Sent: 22 November 2013 16:15
To: hot at openstreetmap.org
Subject: Re: [HOT] PHL: making use of building damage data

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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