Probably my problem boils down to :
Which SRID can I use to get data into the coordinate system used inside
the
planet.osm?
But here in Detail:
I need a little help in reading from the mapnik posgis database. I plan to
expand the osmtrackfilter.pl to compare against the local data already
existing in my mapnik-postgis-database. So I tried to get all street-segments
inside a bounding box. For this i tried to select from the database. But
there I have the problem that the coordintesystems are different and I have
no clue how to convert between them.
I want to operate with coordinates compatible to the planet.osm File.
Something like
lat="48.8046469" lon="9.0401476"
So i thought i'll start with
echo "select osm_id,asText(way) from planet_osm_point limit 5;" | psql
gis
Result:
osm_id | astext
-----------+-------------------------------------------
293106148 | POINT(-2876147.15643226 4560658.25114169)
293105894 | POINT(-2874584.97662211 4563768.28055896)
293107003 | POINT(-2871694.69962705 4559831.77530905)
292977203 | POINT(-2871581.82166339 4556767.11400322)
292976398 | POINT(-2870606.29556972 4556208.15857941)
(5 rows)
Well at least I get some data from the database.
Then the next step is to get transformed Data in the coordinate system I
desire ... I did remember WGS-84 was SRID 4326, but either I'm wrong or
whatever. Doing the following
echo "select osm_id,asText(transform(way,4326)) from planet_osm_point
limit
5;" | psql gis
Results is an:
ERROR: AddToPROJ4SRSCache: Cannot find SRID (4326) in spatial_ref_sys
Well I thought I'll have a look into this in "spatial_ref_sys".... but ....
echo "select * from spatial_ref_sys;" | psql gis
Result:
srid | auth_name | auth_srid | srtext | proj4text
------+-----------+-----------+--------+-----------
(0 rows)
Then I found SRID 900913 inside osm2pgsql and tried:
echo "select osm_id,asText(transform(way,900913)) from planet_osm_point
limit
5;" | psql gis
Result:
osm_id | astext
-----------+-------------------------------------------
293106148 | POINT(-2876147.15643226 4560658.25114169)
293105894 | POINT(-2874584.97662211 4563768.28055896)
293107003 | POINT(-2871694.69962705 4559831.77530905)
292977203 | POINT(-2871581.82166339 4556767.11400322)
292976398 | POINT(-2870606.29556972 4556208.15857941)
(5 rows)
Well, this seems to be the same SRID which is used inside the Database.
So my Question is:
Which SRID can I use to get into the coordinate system I want?
Jörg
http://www.ostertag.name/
--
Jörg (Germany, Tettnang)
http://www.ostertag.name/
_______________________________________________
dev mailing list
[email protected]
http://lists.openstreetmap.org/listinfo/dev
