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<p class=MsoNormal>Hi,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal> I
have been using GDAL for SDTS raster terrain format for reading DDF files
provided by USGS. To get the exact interpolated elevation at a particular
point, I used the logic in <a
href="http://en.wikipedia.org/wiki/Bilinear_interpolation">http://en.wikipedia.org/wiki/Bilinear_interpolation</a>.
For verifying whether the values match exactly, I used Global Mapper but I find
that the variation of around 6 to 10 occurs and some places around 20. I tried
my code on various samples and in almost every sample I get the same
observation. I am sure I am missing something. I am attaching the CPP file
along with the makefile in this mail. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thank You,<o:p></o:p></p>
<p class=MsoNormal>Kart<o:p></o:p></p>
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