<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<title></title>
</head>
<body text="#000000" bgcolor="#ffffff">
<font size="-1"><font face="Helvetica, Arial, sans-serif">Roland,<br>
<br>
I already had an entry for 000 in the transparency list, but I did
not have "Reset no data value" checked. But when I try that, it
immediately "unchecks" when I click "Apply" or "OK", so I am seeing no
change in the image.<br>
<br>
Thanks,<br>
Jim<br>
</font></font><br>
On 05/19/2010 08:41 PM, Roland Hill wrote:
<blockquote cite="mid:4BF4933E.1070904@FourWindsTechnology.com.au"
type="cite">
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<font size="+1">Jim,<br>
<br>
>From memory there is only one no-data value in a geotiff, so I
guess
whether you invalidate all bands at a particular pixel if just one of
them has the no-data value is a matter of preference. You can achieve
what you want though by right-clicking the raster, get into the
Properties, then click Transparency. Add a new transparency set to the
pixel list at the bottom and type in your RGB values. You may need to
'Reset no data value' as well.<br>
<br>
Roland</font>
<div class="moz-signature">
<title></title>
<br>
</div>
<br>
On 19/05/10 05:46, Jim Hammack wrote:
<blockquote cite="mid:4BF2EE8C.4020703@GotSlack.org" type="cite">
<meta http-equiv="content-type"
content="text/html; charset=ISO-8859-1">
<font size="-1"><font face="Helvetica, Arial, sans-serif">I don't
know
if it is my misunderstanding of the way the "no data" flag should be
handled, or if there is a bug in QGIS 1.40 (Linux) geotiff support.<br>
<br>
I have a 24-bit GeoTIFF image in which gdal_warp has set the 'no data'
flag as zero. When I display this image in QGIS, any pixel which has
*either* the red, green or blue value as zero is displayed as
transparent. I expected transparency only when all three values were
zero.<br>
<br>
You can see the geotiff files and jpeg screen captures at <a
moz-do-not-send="true" class="moz-txt-link-freetext"
href="http://gotslack.org/unisips/nodata">http://gotslack.org/unisips/nodata</a>
.<br>
<br>
The file '0255.tif' does not have the no_data flag set (you can see
this in data.jpg), while the file 0255_nodata.tif has no_data set as
zero (nodata.jpg).<br>
<br>
Is this the expected behavior? If so, how can I display this image
with transparency only when all three values (RGB) are zero?<br>
<br>
</font></font>
<pre wrap=""><fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
Qgis-developer mailing list
<a moz-do-not-send="true" class="moz-txt-link-abbreviated"
href="mailto:Qgis-developer@lists.osgeo.org">Qgis-developer@lists.osgeo.org</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext"
href="http://lists.osgeo.org/mailman/listinfo/qgis-developer">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a>
</pre>
</blockquote>
<pre wrap="">
<fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
Qgis-developer mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Qgis-developer@lists.osgeo.org">Qgis-developer@lists.osgeo.org</a>
<a class="moz-txt-link-freetext" href="http://lists.osgeo.org/mailman/listinfo/qgis-developer">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a>
</pre>
</blockquote>
</body>
</html>