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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>You should check the metadata for the
layer. But by convention, cell values on a raster layer are generally the
value at the center of each cell. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Ed Linde<br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, March 04, 2012 8:14
AM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">PostGIS
Users Discussion</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> [postgis-users] SRTM
Raster Geometry question</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Hi All,<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Can someone help me understand a concept with the SRTM raster. My
understanding is that the raster can be thought of as a uniform grid with each
cell having dimension = "90m x 90m" (for SRTM-1 dataset). Now I
am just wondering if the elevation values are 4 values at each vertex or
boundary point of a cell? or is it one elevation value for the 90x90 m^2 area
covered by the cell? I ask because if its the first option, then it would mean
that every point that falls in the cell has it's elevation calculated using
some sort of interpolation between the 4 corner points of the cell to arrive at
this point's altitude. Or do several points that fall into this 90x90 cell get
assigned the same elevation value?<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Would be great if I could get some help understanding this concept
about SRTM rasters.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Cheers,<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Ed <o:p></o:p></span></font></p>
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