[postgis-users] OpenStreetMap to GPS

[Matthew Pulis]

Guys,

I want to plot a list of GPS acquired locations with data originating from
OpenStreetMap. I am thinking to keep everything in GPS projection since
quite near in the future the project is going to be accepting live GPS
readings.

OSM SRID = 900913

Should I consider GPS SRID to be: 4326?

However when I try to transform this geometry:

gis=# select astext(way), asewkt(way), st_srid(way) from malta_roads
gis-# where osm_id = 23561453;

astext
|
asewkt
| st_srid
------------------------------------------------------------------------------------------------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------+---------
 LINESTRING(1582821.69 4304893.15,1582810.45 4304860.01,1582804.55
4304849.75,1582790.4 4304824.81,1582776.19 4304794.61,1582748.85 4304746.72)
| SRID=900913;LINESTRING(1582821.69 4304893.15,1582810.45
4304860.01,1582804.55 4304849.75,1582790.4 4304824.81,1582776.19
4304794.61,1582748.85 4304746.72) |  900913
(1 row)


I get:

gis=# select astext(st_transform(way, 4326)) from malta_roads
gis-# where osm_id = 23561453;
ERROR:  transform: couldn't project point (1.58281e+06 4.30486e+06 0):
failed to load NAD27-83 correction file (-38)
HINT:  PostGIS was unable to transform the point because either no grid
shift files were found, or the point does not lie within the range for which
the grid shift is defined. Refer to the ST_Transform() section of the
PostGIS manual for details on how to configure PostGIS to alter this
behaviour.
gis=#


The data in malta_roads has been acquired from OpenSreetMap in a file .osm.
Data regards Maltese roads.

Thanks for your help and Happy Weekend!

-- 
Matthew Pulis
URL : http://www.matthewpulis.info | http://www.solutions-lab.net
MSN : pulis_matthew[@]hotmail.com
ICQ : 145951110
Skype : solutions-lab.net
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