Changes between Version 70 and Version 71 of WKTRasterTutorial01


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Timestamp:
Jun 21, 2010, 10:52:31 AM (11 years ago)
Author:
pracine
Comment:

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  • WKTRasterTutorial01

    v70 v71  
    352352== Summarizing the elevation values for each buffer and exporting the table to CSV ==
    353353
    354 The last step of our analysis is to summarize the elevation for each buffer by computing 814 weighted mean elevations. "Weighted mean elevation" means that if the area occupied by pixels with an elevation equal to 234 m is greater than the area occupy pixels with an elevation equal to 56 m, then 234 has a higher weight in the equation (proportional to it relative area).This query should do the work:
     354The last step of our analysis is to summarize the elevation for each buffer by computing 814 weighted mean elevations. "Weighted mean elevation" means that if the area occupied by pixels with an elevation equal to 234 m is greater than the area occupy pixels with an elevation equal to 56 m, then 234 has a higher weight in the equation (proportional to it relative area). We also have to convert all the geometries resulting from the intersection operation to a projected spatial reference system appropriate for area measurements, in this case the same one in which was the caribou layer originally (Quebec Lambert, SRID 32198). This query should do the work:
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    356356{{{