Monday 25 May 2015

Loading raster in postgis and link it with an existing table


Relatively new to PostGIS and I am currently exploring the options to make one of my PostgreSQL Tables spatial. Essentially I want to store a raster object in a table that also contains essential metadata. Every raster in the database has to be uniquely linked to the ID´s and information stored in the table.


I was under the impression that I could just write the raster into the same table (similar as with vectors where I could just add geometry columns)? With a query like this I can only write a raster to a new (non-existing) table, thus creating hundreds of tables if my raster files vary in extent, origin and projection (very likely).:


raster2pgsql -s 32739 -I -C -F -M -Y myfile.tif -t 100x100 Map > rasQuery.sql
psql -U test -h localhost -d test -f rasQuery.sql


My existing table looks like this, where I created a raster column.


CREATE TABLE Map(
id serial PRIMARY KEY,
second_id INT references AreaOfInterest,
RasterFile raster,
RasterType char(250),
RasterAuthor char(250),
Acquisition date,
);



  • What is the standard way to load and link rasters with existing tables? raster2psql fails for me stating that the table map already exists, so I guess I have to specify a column as well? Or did I miss a mandatory command here?


The currently working alternative for me would be to just store the filepath in a text column in the Map Table.


Running PostgreSQL 9.4dev + PostGIS 2. on Debian Linux in a test-environment.




EDIT: I am already a bit further. After adding


rast raster,
filename raster,


to my table and the -a flag in front of map in the raster2pgsql command it returns some new errors. Now it says:


 rt_raster_from_wkb: wkb size (9)  < min size (61)
CONTEXT: COPY map, row 1, column filename: „myfile.tif“

Any ideas?



Answer



I tried your commands and changed


filename raster,

to



filename char(250),

, assuming you meant to use a string for that (and declaring it as a raster is a typo??).


The commands seem to work without -C. With -C, I got some warnings/notices about numeric field overflow and no_data. But I guess that's just something in my data.


What I tried is:


echo  " \
CREATE TABLE Map( \
id serial PRIMARY KEY, \
rast raster, \
filename char(250), \

RasterType char(250), \
RasterAuthor char(250), \
Acquisition date \
);" | psql -U postgres -h localhost -d opengeo

# second_id INT references AreaOfInterest, \ # AreaOfInterest not defined

raster2pgsql -a -s 4326 -I -M -F -C tif_dir/*.tif -t 100x100 public.map | psql -U postgres -h localhost -d opengeo

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