weixj,<br><br>You can get some free samples at <a href="http://www.webgis.com/terr_us1deg.html">http://www.webgis.com/terr_us1deg.html</a><br><br><div class="gmail_quote">On Wed, May 2, 2012 at 1:45 PM, weixj <span dir="ltr"><<a href="mailto:weixj2003ld@163.com" target="_blank">weixj2003ld@163.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="line-height:1.7;font-size:14px;font-family:arial"><div><div class="im">
<div>Thank you for your answer.</div>
</div><div>I want to know that where I can get the free DEM data?</div>
<div>I want a sample data,and test my program.</div>
<div> </div>
<div>Thank you.<br><br><br></div></div><div><div class="h5">
<div></div>
<div></div>
<div><br></div>At 2012-05-02 12:57:41,"Chaitanya kumar CH" <<a href="mailto:chaitanya.ch@gmail.com" target="_blank">chaitanya.ch@gmail.com</a>> wrote:<br>
<blockquote style="PADDING-LEFT:1ex;MARGIN:0px 0px 0px 0.8ex;BORDER-LEFT:#ccc 1px solid">weixj,<br><br>Digital Elevation Model is a type of data. In this context, it is a grid of elevation values stored in a raster file.<br>
DEM refers to height. The underlying raster format can be anything.<br><br>The only reference I found for .gmp format is "Global Mapper Package".<br>Perhaps you can find more on the global mapper forums and by opening it in a binary editor.<br>
<br>If the data is stored as raw data, you may be able to read it after creating a .vrt file to describe it.<br><br>
<div class="gmail_quote">On Wed, May 2, 2012 at 8:03 AM, weixj <span dir="ltr"><<a href="mailto:weixj2003ld@163.com" target="_blank">weixj2003ld@163.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT:1ex;MARGIN:0px 0px 0px 0.8ex;BORDER-LEFT:#ccc 1px solid">
<div style="FONT-SIZE:14px;LINE-HEIGHT:1.7;FONT-FAMILY:arial">
<div>DEM is a data format,and the file name extension has many formats,is it right?</div>
<div>My colleage give me file and its name is 90mDataHeight.gmp,and I use the following code read it,and find that it can not open the file.</div>
<div> </div>
<div>code:</div>
<div>GDALAllRegister();</div>
<div> poDataset=(GDALDataset *)GDALOpen(fileName.toLatin1().data(),GA_ReadOnly);<br> if(poDataset==NULL) <br> {<br> QMessageBox::warning(0,"","can not open file:"+fileName);<br> return false;<br> }</div>
<div> </div>
<div>I do not know why?</div>
<div>How many formats of DEM file?<br><br>Thank you.</div>
<div>
<div></div>
<div></div>
<div><br></div>在 2012-04-25 20:11:45，"Chaitanya kumar CH" <<a href="mailto:chaitanya.ch@gmail.com" target="_blank">chaitanya.ch@gmail.com</a>> 写道：<br></div>
<blockquote style="PADDING-LEFT:1ex;MARGIN:0px 0px 0px 0.8ex;BORDER-LEFT:#ccc 1px solid">
<div class="gmail_extra">sure
<div>
<div><br><br>
<div class="gmail_quote">2012/4/25 weixj <span dir="ltr"><<a href="mailto:weixj2003ld@163.com" target="_blank">weixj2003ld@163.com</a>></span><br>
<blockquote class="gmail_quote" style="PADDING-LEFT:1ex;MARGIN:0px 0px 0px 0.8ex;BORDER-LEFT:#ccc 1px solid">
<div style="FONT-SIZE:14px;LINE-HEIGHT:1.7;FONT-FAMILY:arial">
<div>If the file is DEM?the same?<br><br></div>
<div>
<div>
<div></div>
<div></div>
<div><br></div>At 2012-04-24 19:36:11,"Chaitanya kumar CH" <<a href="mailto:chaitanya.ch@gmail.com" target="_blank">chaitanya.ch@gmail.com</a>> wrote:<br>
<blockquote style="PADDING-LEFT:1ex;MARGIN:0px 0px 0px 0.8ex;BORDER-LEFT:#ccc 1px solid">
<div class="gmail_extra">weixj,<br><br>You can use the -projwin option of gdal_translate utility.<br><br><a href="http://www.gdal.org/gdal_translate.html" target="_blank">http://www.gdal.org/gdal_translate.html</a><br><br>
<div class="gmail_quote">2012/4/24 weixj <span dir="ltr"><<a href="mailto:weixj2003ld@163.com" target="_blank">weixj2003ld@163.com</a>></span><br>
<blockquote class="gmail_quote" style="PADDING-LEFT:1ex;MARGIN:0px 0px 0px 0.8ex;BORDER-LEFT:#ccc 1px solid">
<div style="FONT-SIZE:14px;LINE-HEIGHT:1.7;FONT-FAMILY:arial">
<div>I have a tiff file and four points' coordination(and they are in the range of the min and max value of the coordination of the tiff file,I want to generate a new tiff file,and the edge of it is constructed by the four points.</div>
<div> </div>
<div>Thank you in advance.</div></div><br><br><span title="neteasefooter"><span>
<hr>
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<a href="http://lists.osgeo.org/mailman/listinfo/gdal-dev" target="_blank">http://lists.osgeo.org/mailman/listinfo/gdal-dev</a><br></blockquote></div><br><br clear="all"><br>-- <br>Best regards,<br>Chaitanya kumar CH.<br>
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17.2416N 80.1426E<br></div></div></div></blockquote></div><br><br><span title="neteasefooter"><span>
<hr>
<a href="http://www.lofter.com/" target="_blank">网易Lofter，专注兴趣，分享创作！</a> </span></span></blockquote></div><br><br clear="all"><br>-- <br>Best regards,<br>Chaitanya kumar CH.<br><br><a href="tel:%2B91-9494447584" value="+919494447584" target="_blank">+91-9494447584</a><br>
17.2416N 80.1426E<br></blockquote></div></div></div><br><br><span title="neteasefooter"><span></span></span></blockquote></div><br><br clear="all"><br>-- <br>Best regards,<br>Chaitanya kumar CH.<br><br>+91-9494447584<br>17.2416N 80.1426E<br>