You said you could visualize this table in QGIS? Or were you speaking about a shapefile? You can visualize the rastextets table and the points table the same way.
Pierre > -----Original Message----- > From: Jason Mathis [mailto:[email protected]] > Sent: Tuesday, May 13, 2014 6:30 PM > To: PostGIS Users Discussion; Pierre Racine > Subject: Re: [postgis-users] getting raster values for point from st_value > > Hi Pierre, > > Thanks so much for super quick response. You will have to forgive me I am > fairly new to postgis. > > Creating the table is no problem but how would I check if it overlaps with > my points? > > thanks! > > > > On May 13, 2014 at 4:08:40 PM, Pierre Racine ([email protected]) > wrote: > > > Create a new table with the extents of the raster tiles and check if it > overlaps with your points: > > CREATE TABLE rastextets AS > SELECT rast::geometry > FROM tbl_raster > > Pierre > > > -----Original Message----- > > From: [email protected] [mailto:postgis- > users- > > [email protected]] On Behalf Of Jason Mathis > > Sent: Tuesday, May 13, 2014 5:56 PM > > To: [email protected] > > Subject: [postgis-users] getting raster values for point from > st_value > > > > Hi all, > > > > I have recently loaded a good amount of rasterized shape files into > a db. I > > mainly used gdal_rasterize and raster2pgsql. The shape files were > in NAD83 > > so I used the below commands to rasterized and load. > > > > gdal_rasterize -at -a desc -where "desc='Very High'" -burn 2 -tr 30 > 30 -ot > > byte -a_nodata -99 shape_file.shp raster.tiff > > raster2pgsql -d -s 5070 -t 100x100 -F -I -C -Y raster.tiff tbl_raster > | > psql -d > > raster_db > > > > I had two sets of shape files one set had about 10 burn values and > another > > had about 50. The issue is getting these values out of the raster. I > believe I > > should be using something from this page: > > http://postgis.net/docs/RT_ST_Value.html. > > > > I can visualize this file in QGIS and it looks good, the histogram > shows > > values. I can also use the postgis functions, st_summarystats or > > st_histogram to see some data but I need to be able to query a > given point > > and return the raster value. > > > > I have this: > > > > SELECT ST_Value(rast,(ST_Point( -111.750185, 34.886948))) > > FROM tbl_raster > > WHERE st_intersects(rast, (ST_Point(-111.750185, 34.886948))) > > > > Then i thought oh wait should I set the srid?: > > > > SELECT ST_Value(rast,(ST_SetSRID(ST_Point( -111.750185, > > 34.886948),5070))) > > FROM tbl_raster > > WHERE st_intersects(rast, (ST_SetSRID(ST_Point(-111.750185, > > 34.886948),5070))) > > > > Still I get nothing, then I thought I need to transform so I got this: > > > > SELECT ST_Value(rast,(ST_Transform(ST_SetSRID(ST_Point( - > 111.762866, > > 34.874309),5070),4326))) > > FROM tbl_raster > > WHERE st_intersects(rast, (ST_Transform(ST_SetSRID(ST_Point( - > > 111.762866, 34.874309),5070),4326))) > > > > But in the end nothing. > > > > I did need to add the SRID to the spatial_ref_sys table: > > > > INSERT into spatial_ref_sys (srid, auth_name, auth_srid, > proj4text, srtext) > > values ( 5070, 'EPSG', 5070, '+proj=aea +lat_1=29.5 +lat_2=45.5 > +lat_0=23 > > +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 > +towgs84=0,0,0,0,0,0,0 > > +units=m +no_defs ', 'PROJCS["NAD83 / Conus > > > Albers",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHER > > OID["GRS > > > 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],TOWGS84[0, > > > 0,0,0,0,0,0],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0,AUTHORIT > > > Y["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG > > > ","9122"]],AUTHORITY["EPSG","4269"]],PROJECTION["Albers_Conic_Equal_ > > > Area"],PARAMETER["standard_parallel_1",29.5],PARAMETER["standard_par > > > allel_2",45.5],PARAMETER["latitude_of_center",23],PARAMETER["longitude > > _of_center",- > > > 96],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT[" > > > metre",1,AUTHORITY["EPSG","9001"]],AXIS["X",EAST],AXIS["Y",NORTH],AUT > > HORITY["EPSG","5070"]]’); > > > > But ultimately I have nothing I can’t seem to get any data out > using a query > > with a point value. I am thinking it has to do with the srid? Since I > can > > visually inspect it and see data. > > > > Anyone have any hot ideas as to why I am not seeing data? > > > > Thanks! > > > > > > > > This transmission contains confidential and privileged information > intended > > solely for the party identified above. If you receive this message in > error, > > you must not use it or convey it to others. Please destroy it > immediately > > and contact the sender at (303) 386-3955 or by return e-mail to > the sender. > > _______________________________________________ > postgis-users mailing list > [email protected] > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users > > > This transmission contains confidential and privileged information intended > solely for the party identified above. If you receive this message in error, > you must not use it or convey it to others. Please destroy it immediately > and contact the sender at (303) 386-3955 or by return e-mail to the sender. _______________________________________________ postgis-users mailing list [email protected] http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
