[postgis-users] created linear referencing system
Hi, I have asked this question before and could not get straight answer. I have a shape file which Linear reference capable. How to import such data? If I load the data using shape file loader, would the imported data is linear reference capable. If not how to recreate linear referencing system on imported data? ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
[postgis-users] Are there limitations using a PostGIS out-db raster?
I hope someone has gone through this problem and can shed some light into this
problem :)
I have been trying to import a large raster into a PostGIS 2.0 database and hit
a few stumbling blocks.
Initially when I tried to import the raster using raster2pgsql, I would receive
the following error: rt_band_set_pixel_line: Coordinates out of range
After finding this page (http://trac.osgeo.org/postgis/ticket/1839) and using
gdalinfo I found that the raster exceeded the maximum allowed size of 65535 x
65535.
So I decided to use the out-db functionality by using the -R flag in
raster2pgsql.
From the documentation: Register the raster as a filesystem (out-db) raster,
Only the metadata of the raster and path location to the raster is stored in the
database (not the pixels).
I imported the raster using the following command:
raster2pgsql /gis/Flood/ari100.tif -R | psql -U username database
But when I tried a query:
SELECT ST_Value(rast, ST_PointFromText('POINT(152.9632 -26.4878)')) FROM ari100
I get the following error:
NOTICE: Attempting to get pixel value with out of range raster coordinates:
(23975, 29491)
CONTEXT: PL/pgSQL function st_value line 13 at RETURN
However, if I use GDAL (through Python) to query the raster directly using this
script
(http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/val_at_coord.py)
python val_at_coord.py 152.9632 -26.4878
I can retrieve the value correctly.
I decided to find the extents of the raster in the database:
SELECT ST_Height(rast) As rastheight, ST_Width(rast) As rastwidth from ari100;
rastheight | rastwidth
11602 | 42971
The height is completely incorrect (should be 77138).
So my question is: did I do something wrong (in using raster2pgsql) or is there
a limitation in using out-db rasters with PostGIS?
Tangentially: another option would be for me to import the raster as tiles, but
searching these (even with an index) takes more than a minute. Is there an
optimal tile size I can use for quick querying?
Thanks for your help
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Re: [postgis-users] Are there limitations using a PostGIS out-db raster?
Hey Philip,
You will definitely want to tile your raster. The maximum width x
height permitted for the PostGIS raster type is 65535 x 65535,
regardless of whether or not the raster is in-db or out-db. The other
reason to tile your raster (though this may not apply in your case) is
that the maximum field size permitted by PostgreSQL is 1 GB [1].
As for optimal tile size, I can only suggest two things.
1. Tile sizes = 100 x 100 are best. smaller is faster but consumes
more storage space.
2. If possible, find a tile size that is cleanly divisible from the
raster's dimensions. So for a raster of 42971 x 77138, no tile size =
100 x 100 works cleanly. In these situations, I usually just go 50 x 50
or something in that neighborhood.
-bborie
[http://www.postgresql.org/about/]
On 08/21/2012 03:36 PM, Philip D'Rozario wrote:
I hope someone has gone through this problem and can shed some light into this
problem :)
I have been trying to import a large raster into a PostGIS 2.0 database and
hit
a few stumbling blocks.
Initially when I tried to import the raster using raster2pgsql, I would
receive
the following error: rt_band_set_pixel_line: Coordinates out of range
After finding this page (http://trac.osgeo.org/postgis/ticket/1839) and using
gdalinfo I found that the raster exceeded the maximum allowed size of 65535 x
65535.
So I decided to use the out-db functionality by using the -R flag in
raster2pgsql.
From the documentation: Register the raster as a filesystem (out-db) raster,
Only the metadata of the raster and path location to the raster is stored in
the
database (not the pixels).
I imported the raster using the following command:
raster2pgsql /gis/Flood/ari100.tif -R | psql -U username database
But when I tried a query:
SELECT ST_Value(rast, ST_PointFromText('POINT(152.9632 -26.4878)')) FROM
ari100
I get the following error:
NOTICE: Attempting to get pixel value with out of range raster coordinates:
(23975, 29491)
CONTEXT: PL/pgSQL function st_value line 13 at RETURN
However, if I use GDAL (through Python) to query the raster directly using
this
script
(http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/val_at_coord.py)
python val_at_coord.py 152.9632 -26.4878
I can retrieve the value correctly.
I decided to find the extents of the raster in the database:
SELECT ST_Height(rast) As rastheight, ST_Width(rast) As rastwidth from ari100;
rastheight | rastwidth
11602 | 42971
The height is completely incorrect (should be 77138).
So my question is: did I do something wrong (in using raster2pgsql) or is
there
a limitation in using out-db rasters with PostGIS?
Tangentially: another option would be for me to import the raster as tiles,
but
searching these (even with an index) takes more than a minute. Is there an
optimal tile size I can use for quick querying?
Thanks for your help
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--
Bborie Park
Programmer
Center for Vectorborne Diseases
UC Davis
530-752-8380
bkp...@ucdavis.edu
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[postgis-users] Package Maintainers Please Update List
I've put together a preliminary listings of PostGIS distributions I know about. I would appreciate it if package maintainers can update it and provide links to any helpful instructions relevant to your distribution. http://trac.osgeo.org/postgis/wiki/UsersWikiPackages Thanks, Regina http://www.postgis.us ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
