Hello,<span style="color: rgb(255, 0, 0);"></span><br><br>I think that there is no such difference in reading the geotiff, either it is a DEM or anything else.<br>So read the geotiff image data and use it as is. Means it does not matter that the data is DEM or pixel value. The DEM data which is in geotiff format means that the values stored in it are height.
<br><br>Also the value stored in geotiff is always used as it is and it is not relative to anyother value.<br><br>The ModelTiepointTag stores the top left location of your geotiff image. And ModelPixelScaleTag stores the pixel size of your geotiff image.
<br><br>Vineet Bhargava<br>India<br><br>Firstly I am new to the geotiff world . <br><br><br>I am trying to read DEM data which is supplied in geotiff format. Its<br>geotiff image with 181 rows x 181 cols<br>I wrote some code to read the basic tags. And they are as follows
<br><br>SAMPLESPERPIXEL 1<br>TIFFTAG_BITSPERSAMPLE 16<br>TIFFTAG_PHOTOMETRIC 1 (1 /* min value is black */ )<br>TIFFTAG_PLANARCONFIG 1 ( single plane image)<br><br>Now my doubt how do I read the height data stored in this Geotiff Image
<br>?<br>And is this height stored relative to some value ( like any value seen<br>in ModelTiepointTag .. )<br><br>Any API's in libgeotiff / pointers on handling Digital Elevation data<br>in geotiff will be appreciated .
<br><br><br><br>FYI ..<br>This is the Geotiff info for the input data<br><br>Geotiff_Information:<br> Version: 1<br> Key_Revision: 1.0<br> Tagged_Information:<br> ModelTiepointTag (2,3):<br> 0 0 0
<br> 6.99861111 54.0013889 0<br> ModelPixelScaleTag (1,3):<br> 0.00277778 0.00277778 0<br> End_Of_Tags.<br> Keyed_Information:<br> GTModelTypeGeoKey (Short,1): ModelTypeGeographic
<br> GTRasterTypeGeoKey (Short,1): RasterPixelIsArea<br> GeographicTypeGeoKey (Short,1): GCS_WGS_84<br> GeogCitationGeoKey (Ascii,6): "wgs84"<br> GeogAngularUnitsGeoKey (Short,1): Angular_Degree
<br> End_Of_Keys.<br> End_Of_Geotiff.<br><br><br>Thanks in advance,<br>--Chandrakant<br><br><div><span class="gmail_quote">On 9/6/06, <b class="gmail_sendername"><a href="mailto:geotiff-request@lists.maptools.org">
geotiff-request@lists.maptools.org</a></b> <<a href="mailto:geotiff-request@lists.maptools.org">geotiff-request@lists.maptools.org</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
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<br>than "Re: Contents of Geotiff digest..."<br><br><br>Today's Topics:<br><br> 1. Processing Elevation data in Geotiff<br> (Chandrakant Mohire (RBIN/ECM2))<br><br><br>----------------------------------------------------------------------
<br><br>Message: 1<br>Date: Wed, 6 Sep 2006 14:58:07 +0530<br>From: "Chandrakant Mohire (RBIN/ECM2)" <<a href="mailto:Chandrakant.M@in.bosch.com">Chandrakant.M@in.bosch.com</a>><br>Subject: [Geotiff] Processing Elevation data in Geotiff
<br>To: <<a href="mailto:geotiff@lists.maptools.org">geotiff@lists.maptools.org</a>><br>Message-ID:<br> <<a href="mailto:6222DD7606D1314C85F63D9CF40207E00304C87C@kormail02.in.bosch.com">6222DD7606D1314C85F63D9CF40207E00304C87C@kormail02.in.bosch.com
</a>><br>Content-Type: text/plain; charset="us-ascii"<br><br>Hello ,<br><br>Firstly I am new to the geotiff world .<br><br><br>I am trying to read DEM data which is supplied in geotiff format. Its<br>geotiff image with 181 rows x 181 cols
<br>I wrote some code to read the basic tags. And they are as follows<br><br>SAMPLESPERPIXEL 1<br>TIFFTAG_BITSPERSAMPLE 16<br>TIFFTAG_PHOTOMETRIC 1 (1 /* min value is black */ )<br>TIFFTAG_PLANARCONFIG 1 ( single plane image)
<br><br>Now my doubt how do I read the height data stored in this Geotiff Image<br>?<br>And is this height stored relative to some value ( like any value seen<br>in ModelTiepointTag .. )<br><br>Any API's in libgeotiff / pointers on handling Digital Elevation data
<br>in geotiff will be appreciated .<br><br><br><br>FYI ..<br>This is the Geotiff info for the input data<br><br>Geotiff_Information:<br> Version: 1<br> Key_Revision: 1.0<br> Tagged_Information:<br> ModelTiepointTag (2,3):
<br> 0 0 0<br> 6.99861111 54.0013889 0<br> ModelPixelScaleTag (1,3):<br> 0.00277778 0.00277778 0<br> End_Of_Tags.<br> Keyed_Information:
<br> GTModelTypeGeoKey (Short,1): ModelTypeGeographic<br> GTRasterTypeGeoKey (Short,1): RasterPixelIsArea<br> GeographicTypeGeoKey (Short,1): GCS_WGS_84<br> GeogCitationGeoKey (Ascii,6): "wgs84"
<br> GeogAngularUnitsGeoKey (Short,1): Angular_Degree<br> End_Of_Keys.<br> End_Of_Geotiff.<br><br><br>Thanks in advance,<br>--Chandrakant<br><br><br><br><br><br><br><br>-------------- next part --------------<br>
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