<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Hi Pierre,</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Thanks so much for super quick response. You will have to forgive me I am fairly new to postgis. </div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Creating the table is no problem but how would I check if it overlaps with my points? </div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">thanks!</div> <div id="bloop_sign_1400020101137347072" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px"><br></div></div> <br><p style="color:#000;">On May 13, 2014 at 4:08:40 PM, Pierre Racine (<a href="mailto:pierre.racine@sbf.ulaval.ca">pierre.racine@sbf.ulaval.ca</a>) wrote:</p> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>Create a new table with the extents of the raster tiles and check if it overlaps with your points:
<br>
<br>CREATE TABLE rastextets AS
<br>SELECT rast::geometry
<br>FROM tbl_raster
<br>
<br>Pierre
<br>
<br>> -----Original Message-----
<br>> From: postgis-users-bounces@lists.osgeo.org [mailto:postgis-users-
<br>> bounces@lists.osgeo.org] On Behalf Of Jason Mathis
<br>> Sent: Tuesday, May 13, 2014 5:56 PM
<br>> To: postgis-users@lists.osgeo.org
<br>> Subject: [postgis-users] getting raster values for point from st_value
<br>>
<br>> Hi all,
<br>>
<br>> I have recently loaded a good amount of rasterized shape files into a db. I
<br>> mainly used gdal_rasterize and raster2pgsql. The shape files were in NAD83
<br>> so I used the below commands to rasterized and load.
<br>>
<br>> gdal_rasterize -at -a desc -where "desc='Very High'" -burn 2 -tr 30 30 -ot
<br>> byte -a_nodata -99 shape_file.shp raster.tiff
<br>> raster2pgsql -d -s 5070 -t 100x100 -F -I -C -Y raster.tiff tbl_raster | psql -d
<br>> raster_db
<br>>
<br>> I had two sets of shape files one set had about 10 burn values and another
<br>> had about 50. The issue is getting these values out of the raster. I believe I
<br>> should be using something from this page:
<br>> http://postgis.net/docs/RT_ST_Value.html.
<br>>
<br>> I can visualize this file in QGIS and it looks good, the histogram shows
<br>> values. I can also use the postgis functions, st_summarystats or
<br>> st_histogram to see some data but I need to be able to query a given point
<br>> and return the raster value.
<br>>
<br>> I have this:
<br>>
<br>> SELECT ST_Value(rast,(ST_Point( -111.750185, 34.886948)))
<br>> FROM tbl_raster
<br>> WHERE st_intersects(rast, (ST_Point(-111.750185, 34.886948)))
<br>>
<br>> Then i thought oh wait should I set the srid?:
<br>>
<br>> SELECT ST_Value(rast,(ST_SetSRID(ST_Point( -111.750185,
<br>> 34.886948),5070)))
<br>> FROM tbl_raster
<br>> WHERE st_intersects(rast, (ST_SetSRID(ST_Point(-111.750185,
<br>> 34.886948),5070)))
<br>>
<br>> Still I get nothing, then I thought I need to transform so I got this:
<br>>
<br>> SELECT ST_Value(rast,(ST_Transform(ST_SetSRID(ST_Point( -111.762866,
<br>> 34.874309),5070),4326)))
<br>> FROM tbl_raster
<br>> WHERE st_intersects(rast, (ST_Transform(ST_SetSRID(ST_Point( -
<br>> 111.762866, 34.874309),5070),4326)))
<br>>
<br>> But in the end nothing.
<br>>
<br>> I did need to add the SRID to the spatial_ref_sys table:
<br>>
<br>> INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext)
<br>> values ( 5070, 'EPSG', 5070, '+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23
<br>> +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0
<br>> +units=m +no_defs ', 'PROJCS["NAD83 / Conus
<br>> Albers",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHER
<br>> OID["GRS
<br>> 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],TOWGS84[0,
<br>> 0,0,0,0,0,0],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0,AUTHORIT
<br>> Y["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG
<br>> ","9122"]],AUTHORITY["EPSG","4269"]],PROJECTION["Albers_Conic_Equal_
<br>> Area"],PARAMETER["standard_parallel_1",29.5],PARAMETER["standard_par
<br>> allel_2",45.5],PARAMETER["latitude_of_center",23],PARAMETER["longitude
<br>> _of_center",-
<br>> 96],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["
<br>> metre",1,AUTHORITY["EPSG","9001"]],AXIS["X",EAST],AXIS["Y",NORTH],AUT
<br>> HORITY["EPSG","5070"]]’);
<br>>
<br>> But ultimately I have nothing I can’t seem to get any data out using a query
<br>> with a point value. I am thinking it has to do with the srid? Since I can
<br>> visually inspect it and see data.
<br>>
<br>> Anyone have any hot ideas as to why I am not seeing data?
<br>>
<br>> Thanks!
<br>>
<br>>
<br>>
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<br>
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