<div dir="ltr">Yes. The result of that query is the value for the first pixel. If you're going to dump out all the values of all tiles, you're better off with something like ST_DumpValues instead...<div><br></div><div><a href="http://postgis.net/docs/manual-2.1/RT_ST_DumpValues.html">http://postgis.net/docs/manual-2.1/RT_ST_DumpValues.html</a><br></div><div><br></div><div>If you're scanning the whole MODIS scene(s), nothing beats the performance of directly going to the files.</div><div><br></div><div>Since you're new, two bits of advice...</div><div><br></div><div>1. If your raster data is read-only, keep the raster data outside the database using out-db (raster2pgsql's -R flag)</div><div><br></div><div>2. There is no optimal tile size for storing data in-db as that is highly dependent on the source raster data (# of bands, pixel types of each band). For out-db though, I strongly recommend using the block size specified by the output of gdalinfo. The reason for this is that GDAL is used to get the data from the out-db raster.</div><div><br></div><div><font face="monospace, monospace">$ gdalinfo myraster.tif</font></div><div><font face="monospace, monospace"><br></font></div><div><div><font face="monospace, monospace">Driver: GTiff/GeoTIFF</font></div><div><font face="monospace, monospace">Files: myraster.tif</font></div><div><font face="monospace, monospace">Size is 1405, 621</font></div><div><font face="monospace, monospace">Coordinate System is:</font></div><div><font face="monospace, monospace">GEOGCS["NAD83",</font></div><div><font face="monospace, monospace"> DATUM["North_American_Datum_1983",</font></div><div><font face="monospace, monospace"> SPHEROID["GRS 1980",6378137,298.2572221010002,</font></div><div><font face="monospace, monospace"> AUTHORITY["EPSG","7019"]],</font></div><div><font face="monospace, monospace"> AUTHORITY["EPSG","6269"]],</font></div><div><font face="monospace, monospace"> PRIMEM["Greenwich",0],</font></div><div><font face="monospace, monospace"> UNIT["degree",0.0174532925199433],</font></div><div><font face="monospace, monospace"> AUTHORITY["EPSG","4269"]]</font></div><div><font face="monospace, monospace">Origin = (-125.020833333333329,49.937500000002032)</font></div><div><font face="monospace, monospace">Pixel Size = (0.041666666666670,-0.041666666666670)</font></div><div><font face="monospace, monospace">Metadata:</font></div><div><font face="monospace, monospace"> AREA_OR_POINT=Area</font></div><div><font face="monospace, monospace">Image Structure Metadata:</font></div><div><font face="monospace, monospace"> INTERLEAVE=BAND</font></div><div><font face="monospace, monospace">Corner Coordinates:</font></div><div><font face="monospace, monospace">Upper Left (-125.0208333, 49.9375000) (125d 1'15.00"W, 49d56'15.00"N)</font></div><div><font face="monospace, monospace">Lower Left (-125.0208333, 24.0625000) (125d 1'15.00"W, 24d 3'45.00"N)</font></div><div><font face="monospace, monospace">Upper Right ( -66.4791667, 49.9375000) ( 66d28'45.00"W, 49d56'15.00"N)</font></div><div><font face="monospace, monospace">Lower Right ( -66.4791667, 24.0625000) ( 66d28'45.00"W, 24d 3'45.00"N)</font></div><div><font face="monospace, monospace">Center ( -95.7500000, 37.0000000) ( 95d45' 0.00"W, 37d 0' 0.00"N)</font></div><div><font face="monospace, monospace">Band 1 <b><font size="4">Block=1405x1</font></b> Type=Float32, ColorInterp=Gray</font></div><div><font face="monospace, monospace"> Min=10.920 Max=49.370 </font></div><div><font face="monospace, monospace"> Minimum=10.920, Maximum=49.370, Mean=29.345, StdDev=5.782</font></div><div><font face="monospace, monospace"> NoData Value=-9999</font></div></div><div><br></div><div> -bborie</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Apr 21, 2015 at 9:18 AM, Albury, Carl -FS <span dir="ltr"><<a href="mailto:calbury@fs.fed.us" target="_blank">calbury@fs.fed.us</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal">Hi<u></u><u></u></p>
<p class="MsoNormal">I’m new to PostGIS so please bear with me.<u></u><u></u></p>
<p class="MsoNormal">I’m working with MODIS data that I tiled using the auto tile switch in raster2pgsql resulting in 13250 82x94 tiles.<u></u><u></u></p>
<p class="MsoNormal">When I try to query for pixel values using ST_Value, such as:<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">SELECT<u></u><u></u></p>
<p class="MsoNormal"> ST_Value(rast, 2, 1,1) -- multiband raster<u></u><u></u></p>
<p class="MsoNormal">FROM<u></u><u></u></p>
<p class="MsoNormal"> MODIS_test;<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I get a value for each tile, not for each pixel (I assume the value is for the first pixel in the tile?).<u></u><u></u></p>
<p class="MsoNormal">If I want to query each pixel do I need to loop through each tile and have a sub loop for each pixel in that tile? If so I can’t figure out the syntax to designate the tiles vs pixels.<u></u><u></u></p>
<p class="MsoNormal"><span style="color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal">Thanks very much,<u></u><u></u></p>
<p class="MsoNormal">Carl<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
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