Yes. This is really at the convenience of your application. Pierre
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Stephen Crawford Sent: Monday, May 09, 2011 12:13 PM To: PostGIS Users Discussion Subject: Re: [postgis-users] gridded data Great info, thanks a lot. If you think it best to store each weather variable in a separate table, then I imagine that would be by date too, i.e. a table named "max_temp_05_09_2011" or something like that? Thanks, Steve On 5/9/2011 11:55 AM, Pierre Racine wrote: >> I want to use daily weather variables that are in a grid for USA. I >> would want store the daily variables ( a new grid each day) so I can >> have a database that will allow the client to send a point lat/lon >> and then return a calculation based on a few days worth of two or >> three variables. >> >> Do I store each day (or variable) as a new table? How does a grid >> get stored in postgres? Is this a job for PostGIS Raster (though I >> do not want to produce images, just queries at a point)? > Hi Steve, > > PostGIS with the raster extension is just the right tool to do that. I would > recommend to store each weather variable in a separate table. > > To tile (with the raster2pgsal.py -k option) or not to tile your rasters > depends on their size. Generally it is better to tile them. > > Assuming your rasters are in a geographic coordinate system, you can then > query the temperature for a lat/long like this (if they are tiled): > > SELECT ST_Value(rast, ST_MakePoint(lat, long) as temp FROM > yourrastertable WHERE ST_Intersects(rast, ST_MakePoint(lat, long)) > > Just omit the WHERE clause if you don't tile them when loading. > > Try also: > > SELECT ST_Value(rast, ST_MakePoint(lat, long) as temp FROM > yourrastertable WHERE ST_DWithin(rast, ST_MakePoint(lat, long), 0) > > Which might be faster... > > Please refer to the PostGIS Raster tutorials: > > http://trac.osgeo.org/postgis/wiki/WKTRaster > > Pierre > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users -- Stephen Crawford Center for Environmental Informatics The Pennsylvania State University [email protected] 814.865.9905 _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
