I work with Will on the CAP103 project and succeeded yesterday to calculate
daily statistics for the CAP103 geographic zone.
I adapted a python script originally written by Sebastien
Pierrel. The OsmApi module contains changeset functions that are usefull
to interrogate the OSM API and obtain the history of objects.
For
a BBOX, a specific contributor and a date range, we can interrogate the
OSM API an list the changesets. Below are examples for changeset
ID=16327554.
And looking more in detail about the Changeset
function, I see that there are collection of objects
edited. We should be able with this historical data to calculate more
detailed statistics (ie. objects created, modified, deleted).
It
is quitee easy to treat this with Python script but there might be some limits
when interrogating the OSM API. Then, it is possible to shorten the period
analyzed.
For each changeset, you have the creation date and the Comment variable.
Example : Changeset collection item using osmApi.ChangesetsGet function
{16327554:
{u'uid': 1339602, u'open': False, u'min_lat': u'19.626711',
u'created_at': u'2013-05-28T18:08:50Z', u'max_lon': u'-71.9161975',
u'tag': {u'comment': u'Projet cap103 edition a distance', u'created_by':
u'JOSM/1.5 (5939 fr) Linux Ubuntu 12.04.2 LTS'}, u'user': u'John
Carlo', u'max_lat': u'19.7288581', u'min_lon': u'-71.9958761',
u'closed_at': u'2013-05-28T19:31:18Z', u'id': 16327554}}
The
osmApi.ChangesetDownload is also usefull to obtain the history of
objects. This list the various objects edited (ie. node, way, relation),
their status (created, edited, deleted) and Tags.
Objects Collection
using function osmApi.ChangesetDownload(changeset id)
{u'action':
u'create', u'data': {u'changeset': 16327554, u'uid': 1339602,
u'timestamp': u'2013-05-28T18:08:53Z', u'lon': -71.9755596, u'visible':
True, u'version': 1, u'user': u'John Carlo', u'lat': 19.6543342, u'tag':
{u'addr:housenumber': u'0869H-10-100', u'addr:street': u'Village
Nativity Terrier-Rouge'}, u'id': 2323372166L}, u'type': u'node'}
{u'action':
u'modify', u'data': {u'changeset': 16327554, u'uid': 1339602,
u'timestamp': u'2013-05-28T18:08:53Z', u'nd': [330537291, 1028932465,
330525425, 330600909, 330585780, 1028932361, 2262221592L, 330547550,
2316028253L, 330581577, 330533684, 330575573, 330525334, 330538780,
330551803, 330540720, 2312207865L, 330541763, 330557722, 330534653,
330560877, 330555513, 330539911, 330579005, 330575077, 330584161,
330538354, 330548147, 2323372173L, 330559532, 330527407, 330531707,
330600600, 330531364, 330549754, 330541775, 330587579],
u'tag': {u'name': u'Route Nationale # 6', u'haiti:code': u'RN',
u'haiti:import_file': u'3.osm', u'haiti:source_file':
u'intersect8_polyid__3.shp', u'haiti:objectid': u'1431',
u'haiti:source': u'CNIGS and CartONG', u'haiti:type': u'Nationale',
u'ref': u'RN 6', u'haiti:nom2': u'RN6', u'haiti:nom': u'Nationale no 6',
u'highway': u'primary'}, u'visible': True, u'version': 3, u'user':
u'John Carlo', u'id': 222650616}, u'type': u'way'}
{u'action':
u'modify', u'data': {u'changeset': 16327554, u'uid': 1339602,
u'timestamp': u'2013-05-28T18:28:07Z', u'nd': [2322223911L, 2323407166L,
2322223910L, 2322223673L, 2322223674L, 2322223911L], u'tag':
{u'building': u'yes'}, u'visible': True, u'version': 2, u'user': u'John
Carlo', u'id': 223313287}, u'type': u'way'}
{u'action':
u'delete', u'data': {u'changeset': 16327554, u'uid': 1339602,
u'timestamp': u'2013-05-28T18:28:08Z', u'nd': [], u'tag': {},
u'visible': False, u'version': 2, u'user': u'John Carlo',
u'id': 223438254}, u'type': u'way'}
Pierre
>________________________________
> De : Paul Norman <[email protected]>
>À : 'william skora' <[email protected]>; [email protected]
>Envoyé le : Vendredi 24 mai 2013 5h23
>Objet : Re: [OSM-dev] Querying Changeset Tags in OSM API
>
>
>
>You could do this with pgsnapshot (or if just doing analysis, osm2pgsql) in
>the same database as changesetmd, and then do JOINs between the tables to get
>objects that were last modified in a changeset that had a particular tag.
>
>This may be hampered by two things
>- A lack of minutely diff support by changesetmd
>- A lack of schema support in most OSM software. See
>http://www.postgresql.org/docs/9.1/static/ddl-schemas.html in the postgresql
>docs for information about schemas. osmosis
>
>This probably isn’t exactly what you want, but I think it’s the best there is
>at this point.
>
>From:william skora [mailto:[email protected]]
>Sent: Sunday, May 05, 2013 8:50 AM
>To: [email protected]
>Subject: [OSM-dev] Querying Changeset Tags in OSM API
>
>
>Hi,
>
>I'm curious if there's any current capabilities to filter entire objects based
>on the tags used on the changeset. I'm on the CAP103 team in Northern Haiti
>with HOT and we'd like to filter objects modified by mappers that we are
>training by querying changesets, instead of adding a tag to each object within
>a specific bbox and a changeset tag with something like source:Project=CAP103.
>
>Ideally, I'd prefer to do this through a server-side interface (XAPI) but
>would be open to client-side filtering options like osmosis.
>as I understand, Overpass isn't currently capable to do this; it is only able
>to query within
>Any advice and help is appreciated.
>
>Regards,
>Will
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>
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