Changes between Version 49 and Version 50 of WKTRasterTutorial01


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Timestamp:
Jun 11, 2010, 1:43:15 PM (11 years ago)
Author:
pracine
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  • WKTRasterTutorial01

    v49 v50  
    33''Pierre Racine, June 2010''
    44
    5 This tutorial will show you how to do a very classical raster/vector analysis with PostGIS WKT Raster. Basically the problem is to compute the mean elevation for buffers surrounding a series of point representing caribou observations. You can do this kind of analysis pretty easily in any GIS package but what is special here and is not easy to do in ANY GIS package is the size of the datasets used (900 MB or raster data), the simplicity of the queries and the speed at which we will get the results. 
     5This tutorial will show you how to do a very classical raster/vector analysis with PostGIS WKT Raster. Basically the problem is to compute the mean elevation for buffers surrounding a series of point representing caribou observations. You can do this kind of analysis pretty easily in any GIS package but what is special here and is not easy to do in ANY GIS package is the size of the datasets used (900 MB or raster data), the simplicity of the queries and the speed at which we will get the results.
    66
    77We will describe the steps mainly on Windows, but Linux gurus will have no problem writing the equivalent commands in their favorite OS. We assume that PostgreSQL, PostGIS and PostGIS WKT Raster are well installed. Refer to the readme file of each software to install them properly. The version used are:
     
    116116{{{
    117117    CREATE INDEX srtm_tiled_rast_gist_idx ON srtm_tiled USING GIST (ST_ConvexHull(rast));
     118}}}
     119
     120A quick overview of the properties of the raster table can be displayed with the following command:
     121
     122{{{
     123    SELECT (md).*, (mdb).* FROM (SELECT ST_Metadata(rast) md, ST_BandMetadata(rast) md FROM srtm_tiled) foo;
    118124}}}
    119125
     
    335341    ORDER BY id;
    336342}}}
     343
     344== Conclusion ==
     345
     346You can find more info on PostGIS WKT Raster [wiki:WKTRaster in this page].