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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Doesn’t the second example (One raster, several bands) similar to your case in the doc?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><a href="http://postgis.net/docs/RT_ST_MapAlgebra.html">http://postgis.net/docs/RT_ST_MapAlgebra.html</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Pierre<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> postgis-users [mailto:postgis-users-bounces@lists.osgeo.org]
<b>On Behalf Of </b>David Haynes<br>
<b>Sent:</b> Tuesday, November 17, 2015 9:48 AM<br>
<b>To:</b> postgis-users@lists.osgeo.org<br>
<b>Subject:</b> [postgis-users] Raster calculation on 3d raster (stack)<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hello,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I have a mulibanded raster and I am wondering if I can apply any of the raster processing functions (min, max, mean, stdev) to multibanded rasters. Specifically, I am wondering if these functions will be able to applied to the z-axis. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Here is an example, I have worked up in python starting with two 2d arrays.<o:p></o:p></p>
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<p class="MsoNormal">x = [[1,4,5,6], [3,5,6,2]]<o:p></o:p></p>
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<p class="MsoNormal">z = [[2,7,8,9], [8,3,5,9]]<o:p></o:p></p>
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<p class="MsoNormal">convert to np.array<o:p></o:p></p>
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<p class="MsoNormal">y = np.dstack((np.array(x), np.array(z)))<o:p></o:p></p>
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<p class="MsoNormal">>>> y.sum(2)<o:p></o:p></p>
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<p class="MsoNormal">array([[ 3, 11, 13, 15],<o:p></o:p></p>
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<p class="MsoNormal"> [11, 8, 11, 11]])<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I want to apply the raster processing functions to the z-axis and I am wondering if I can do it in PostGIS? It seems like the mapalgebra call back functions could do this, but I am having difficulty finding an example.<o:p></o:p></p>
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