<DIV>Thk u for your answer.</DIV>
<DIV>Yes,they give the same output except Type.</DIV>
<DIV> </DIV>
<DIV>Driver: PNG/Portable Network Graphics<BR>Files: SRTM_GTOPO_u30_n090e060.png<BR>Size is 4800, 6000<BR>Coordinate System is `'<BR>Corner Coordinates:<BR>Upper Left ( 0.0, 0.0)<BR>Lower Left ( 0.0, 6000.0)<BR>Upper Right ( 4800.0, 0.0)<BR>Lower Right ( 4800.0, 6000.0)<BR>Center ( 2400.0, 3000.0)<BR>Band 1 Block=4800x1 Type=Byte, ColorInterp=Gray<BR></DIV>
<DIV>1. I want to know that when I should use '-ot Byte ' and when use ' -ot UInt16 '?</DIV>
<DIV>2. when I use -ot UInt16 ',Must I perform histogram equalization on it?</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV></DIV><BR>
<BLOCKQUOTE id="isReplyContent" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">weixj2003ld,<BR><BR>I couldn't open the link.<BR>Try "gdalinfo -mm des.png" on both the output images. I think they will both give the same output. UInt16 should give a dark image unless you perform histogram equalization on it.<BR><BR>
<DIV class="gmail_quote">2010/5/11 weixj2003ld <SPAN dir="ltr"><<A href="mailto:weixj2003ld@163.com">weixj2003ld@163.com</A>></SPAN><BR>
<BLOCKQUOTE class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">
<DIV>I download a elevation data (SRTM,GTOPO30) from <A href="http://glcfapp.glcf.umd.edu:8080/esdi/index.jsp" target="_blank">http://glcfapp.glcf.umd.edu:8080/esdi/index.jsp</A></DIV>
<DIV> </DIV>
<DIV> use </DIV>
<DIV>gdal_translate -b 1 -of PNG -ot Byte source.tif des.png</DIV>
<DIV>and </DIV>
<DIV>gdal_translate -b 1 -of PNG -ot UInt16 source.tif des.png</DIV>
<DIV>differently,</DIV>
<DIV>with parameter 'UInt16',I get a black picture,with Byte,get a different one,why?</DIV>
<DIV>BTW,I want to get a png file from elevation data(.tif),must I use command gdal_translate?</DIV>
<DIV>Thk u in advance.</DIV>
<DIV> </DIV></BLOCKQUOTE></DIV><BR><BR clear="all"><BR>-- <BR>Best regards,<BR>Chaitanya kumar CH.<BR>/tʃaɪθənjə/ /kʊmɑr/ <BR>+91-9848167848<BR>17.2416N 80.1426E<BR></BLOCKQUOTE><br><br><span title="neteasefooter"/><hr/>
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