[OSM-dev] shortest streets
Lennard
ldp at xs4all.nl
Thu Sep 17 10:54:42 BST 2009
Stephan Knauss wrote:
> So could you specify a better projection that would be equidistant? The
> data here uses 900913.
> Would 4326 be equidistant?
FWIW, this is what I'm using on my cycle map:
ST_length_spheroid(transform(way,4326),'SPHEROID["WGS
84",6378137,298.257223563,AUTHORITY["EPSG","7030"]]')
Note the space in "WGS 84".
> Is there a difference between st_length() and length()? They both return
> the same values (at least for 900913).
Same thing, but the ST_ is the newer version, thought up to distinguih
spatial calls.
> Postgis manual has a similar query to sum up the length of ways. Why is
> it working there? Different projection?
I guess it's just an example of the ST_length() function as is, not
taking into account any projection issues.
--
Lennard
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