<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7650.28">
<TITLE>Processing Elevation data in Geotiff</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/rtf format -->
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Hello ,</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Firstly</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">I am </FONT> <FONT SIZE=2 FACE="Arial">new to the geotiff world</FONT><FONT SIZE=2 FACE="Arial"> .</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">I am trying to read DEM data which is supplied in geotiff</FONT><FONT SIZE=2 FACE="Arial"> format.</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> I</FONT><FONT SIZE=2 FACE="Arial">ts</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">g</FONT><FONT SIZE=2 FACE="Arial">eotiff</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">image</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">with</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"></FONT> <FONT SIZE=2 FACE="Arial">181</FONT> <FONT SIZE=2 FACE="Arial">rows x</FONT> <FONT SIZE=2 FACE="Arial">181</FONT> <FONT SIZE=2 FACE="Arial">cols</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">I wrote some</FONT> <FONT SIZE=2 FACE="Arial">code to read the</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">basic</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"></FONT> <FONT SIZE=2 FACE="Arial">tags.</FONT> <FONT SIZE=2 FACE="Arial">A</FONT><FONT SIZE=2 FACE="Arial">nd</FONT> <FONT SIZE=2 FACE="Arial">they are as follows</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">SAMPLESPERPIXEL 1</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"></FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> </SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">TIFFTAG_BITSPERSAMPLE 16</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">TIFFTAG_PHOTOMETRIC 1</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> (</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT COLOR="#3366FF" SIZE=2 FACE="Times New Roman">1 /* min</FONT> <FONT COLOR="#3366FF" SIZE=2 FACE="Times New Roman">value is bla</FONT><FONT COLOR="#3366FF" SIZE=2 FACE="Times New Roman">c</FONT><FONT COLOR="#3366FF" SIZE=2 FACE="Times New Roman">k *</FONT><FONT COLOR="#3366FF" SIZE=2 FACE="Times New Roman">/</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT COLOR="#3366FF" SIZE=2 FACE="Times New Roman"> )</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">TIFFTAG_PLANARCONFIG 1</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"></FONT> <FONT SIZE=2 FACE="Arial"> ( single plane image) </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Now my doubt</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">how do I read the height data stored in th</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">is</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> Geotiff Image</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> ?</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">A</FONT><FONT SIZE=2 FACE="Arial">nd</FONT> <FONT SIZE=2 FACE="Arial">is this height stored relative to some value (</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">like</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">any value seen in</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial"></FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">ModelTiepointTag</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"></FONT> <FONT SIZE=2 FACE="Arial"></FONT> <FONT SIZE=2 FACE="Arial">..</FONT> <FONT SIZE=2 FACE="Arial">) </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Any API</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">’</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">s in libgeotiff</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial"> /</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">pointers</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"></FONT> <FONT SIZE=2 FACE="Arial">on handling</FONT> <FONT SIZE=2 FACE="Arial">Digital Elevation data in geotiff will be appreciated</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> .</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">FYI ..</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">This is the</FONT> <FONT SIZE=2 FACE="Arial">Geotiff info</FONT> <FONT SIZE=2 FACE="Arial">for the input data </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Geotiff_Information:</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> Version: 1</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> Key_Revision: 1.0</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> Tagged_Information:</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> ModelTiepointTag (2,3):</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> 0 0 0 </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> 6.99861111 54.0013889 0 </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> ModelPixelScaleTag</FONT> <FONT SIZE=2 FACE="Arial">(1,3):</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> 0.00277778 0.00277778 0 </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> End_Of_Tags.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> Keyed_Information:</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> GTModelTypeGeoKey (Short,1): ModelTypeGeographic</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> GTRasterTypeGeoKey (Short,1): RasterPixelIsArea</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> GeographicTypeGeoKey (Short,1):</FONT> <FONT SIZE=2 FACE="Arial">GCS_WGS_84</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> GeogCitationGeoKey (Ascii,6): "wgs84"</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> GeogAngularUnitsGeoKey (Short,1): Angular_Degree</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> End_Of_Keys.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> End_Of_Geotiff.</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">T</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">hanks</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"></FONT> <FONT SIZE=2 FACE="Arial">in advance,</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">--Chandrakant</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
</BODY>
</HTML>