[Qgis-user] QGIS Openstreetmap plugin

[Stefan Keller]

Hi Polyglot

Just to be sure I'd like to point to the existing OSM plugin for QGIS
[1], which deserves an evaluation and probably needs some care.

Then, although I'm an active PostGIS (Postgres) supporter, I would
recommend Spatialite (SQLite) instead, given you use case.
It's more lightweight because it does not need a server installation
and you probably only use it as a temporary store.

Yours, Stefan


[1] http://wiki.openstreetmap.org/wiki/QGIS_OSM_Plugin

2013/5/18 Jo <winfixit at gmail.com>:
> Hi,
>
> I'm a long time Openstreetmap contributor trying to wrap my brain around
> understanding how to work with QGIS. Quite likely this means I follow the
> opposite path of most.
>
> I managed to convert WFS to SHP, load that SHP in JOSM, the java
> openstreetmap editor and in PostGIS. Translating latin1 to UTF8 and
> Lambert72 to WGS84. Even , to . as the decimal operator.
>
> I also found how to style the data in the shape files.
>
> So far so good.
>
>
> Now I read the chapter in the manual on how to work with OSM data directly
> in QGIS. What I'm missing is a way to work with the tags on the nodes and a
> way to visualise route relations.
>
> The best way is probably to give a concrete example. We have cycle node
> networks. The nodes have rcn_ref tags, usually integers, sometimes START.
>
> The nodes are members in network relations.
>
> The ways between the nodes are members of route relations
>
> The route relations are also members of the network relations.
>
> I want the colour of the buffer around the nodes to be dependent on the
> network relation they belong to.
>
> I want the caption along the routes to come from the note tag of the route
> relations. And I want to draw a buffer along their paths.
>
> Is there a way to access the tags of the relations and the nodes?
>
> Further down the line, I would love to be able to use QGIS to draw
> spiderlike network diagrams of public transportation networks. With ways
> coloured based on the bus lines passing there, 7 colours with an offset.
>
>
>
> At some point I may write a Python plugin myself to work with OSM data. All
> the data would be stored in PostGIS. Only the nodes would have geometries,
> which can be uploaded to the OSM server. Ways would have geometries.
> Relations would have geometries based on their type. But if ways or
> relations are changed the geometry gets updated at the nodes level. Then all
> geometries which use those nodes will have to be recalculated (with a
> trigger function in PostGIS, I guess). I have no idea if such a solution
> would be able to scale. Especially as I would also like to store historic
> versions of the nodes, ways and relations in that DB.
>
> The nodes layer would show all the nodes, not only the ones which have no
> tags. Labels can be queried from the tags in the relations table as well
>
> The ways layer would show all the non closed ways, not sure about the
> roundabouts. Maybe all the ways which aren't areas.
>
> The polygons layer would show all the closed ways (areas) and the
> multipolygon relations. The buildings, the landuse, the boundaries.
>
> The routes layer would show all the route relations
>
>
> I have been giving this some thought:
>
> CREATE TABLE users
> (
>   userid integer PRIMARY KEY,
>   username text
> )
> WITH (
>   OIDS=FALSE
> );
> ALTER TABLE users
>   OWNER TO "Jo";
>
> CREATE TABLE changesets
> (
>   csid integer PRIMARY KEY,
>   cs_userid integer REFERENCES users,
>   csts timestamp
> )
> WITH (
>   OIDS=FALSE
> );
> ALTER TABLE changesets
>   OWNER TO "Jo";
>
> CREATE TABLE nodes
> (
>   nodeid bigint PRIMARY KEY,
>   nd_csid integer REFERENCES changesets,
>   ndversion integer,
>   --ndts timestamp,
>   geog geography
> )
> WITH (
>   OIDS=FALSE
> );
>
> CREATE TABLE ways
> (
>   wayid integer PRIMARY KEY,
>   wy_csid integer REFERENCES changesets,
>   wyversion integer
>   --wyts timestamp
> )
> WITH (
>   OIDS=FALSE
> );
>
> CREATE TABLE rels
> (
>   relid integer PRIMARY KEY,
>   rl_csid integer REFERENCES changesets,
>   rlversion integer
>   --rlts timestamp
> )
> WITH (
>   OIDS=FALSE
> );
>
> CREATE TABLE keys
> (
>   keyid bigserial PRIMARY KEY,
>   k text
> )
> WITH (
>   OIDS=FALSE
> );
> CREATE TABLE vals
> (
>   valueid bigserial PRIMARY KEY,
>   v text
> )
> WITH (
>   OIDS=FALSE
> );
> CREATE TABLE tags
> (
>   tagid bigserial PRIMARY KEY,
>   tg_nodeid bigint REFERENCES nodes,
>   tg_wayid bigint REFERENCES ways,
>   tg_relid bigint REFERENCES rels,
>   tg_keyid bigint REFERENCES keys,
>   tg_valueid bigint REFERENCES vals
> )
> WITH (
>   OIDS=FALSE
> );
>
> CREATE TABLE waynodes
> (
>   wnid bigserial PRIMARY KEY,
>   wn_way bigint REFERENCES ways,
>   wn_node bigint REFERENCES nodes
> )
> WITH (
>   OIDS=FALSE
> );
>
> CREATE TABLE relnodes
> (
>   rnid bigserial PRIMARY KEY,
>   rn_rel bigint REFERENCES rels,
>   rn_node bigint REFERENCES nodes
> )
> WITH (
>   OIDS=FALSE
> );
>
> CREATE TABLE relways
> (
>   rwid bigserial PRIMARY KEY,
>   rw_rel bigint REFERENCES rels,
>   rw_way bigint REFERENCES ways
> )
> WITH (
>   OIDS=FALSE
> );
>
> CREATE TABLE relrelations
> (
>   rrid bigserial PRIMARY KEY,
>   rr_parent bigint REFERENCES rels,
>   rr_child bigint REFERENCES rels
> )
> WITH (
>   OIDS=FALSE
> );
>
>
> Until now I was considering to program this as stored procedures in PostGIS
> and with Python from the command line, but it may make a lot more sense to
> write a QGIS plugin in Python.
>
> My goal is not only to be able to work with the data and visualise it. I
> also need to find a way to prepare open data, available as shape files and
> WFS, for integration in Openstreetmap and subsequently to do quality control
> on it and to assure we keep current with changes coming from upstream and
> the ability to create feedback reports on changes coming from the OSM
> contributors, once they are vetted as genuine.
>
> I'd love to hear your thoughts on all this. I wouldn't be surprised if
> there's something I didn't think about.
>
> Kind regards,
>
> Polyglot
>
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