https://issues.qgis.org/https://issues.qgis.org/favicon.ico2014-11-05T06:39:02ZQGIS Issue TrackingQGIS Application - Bug report #11573: Int images with floating point gain not displayed properlyhttps://issues.qgis.org/issues/11573?journal_id=572052014-11-05T06:39:02ZGiovanni Manghigiovanni.manghi@gmail.com
<ul><li><strong>Status</strong> changed from <i>Open</i> to <i>Feedback</i></li></ul><p>please attach/link sample data.</p> QGIS Application - Bug report #11573: Int images with floating point gain not displayed properlyhttps://issues.qgis.org/issues/11573?journal_id=572122014-11-05T07:18:56ZMatthew Hanson
<ul></ul><p>Link to example data.</p>
<p>TIF NDVI image. Int16, ranging from -26512 to 11716 with a gain of 0.0001:<br /><a class="external" href="http://geo.ags.io/static/2014141_LC8_ndvi.tif">http://geo.ags.io/static/2014141_LC8_ndvi.tif</a></p>
<p>QGIS 2.2 reports numbers as the original ints, and is correct (although without gain) in the above range.</p>
<p>QGIS 2.4, 2.6 reports numbers statistics properly as -2.6512 to 1.1716, but the image is displayed as all 0's.</p>
<p>With the gain removed 2.6 behaves as 2.2.</p>
<p>Same image, with no gain set:<br /><a class="external" href="http://geo.ags.io/static/2014141_LC8_ndvi_nogain.tif">http://geo.ags.io/static/2014141_LC8_ndvi_nogain.tif</a></p> QGIS Application - Bug report #11573: Int images with floating point gain not displayed properlyhttps://issues.qgis.org/issues/11573?journal_id=579332014-12-03T06:09:09ZMatthew Hanson
<ul></ul><p>I would like to request that the "feature" of applying Gain and Offset be reverted until this bug is fix. As it stands QGIS is completely unusable if you store floating point images as Int16 to save space (a very common thing to do for storing indices such as NDVI). We have had to peg our QGIS at 2.2.</p> QGIS Application - Bug report #11573: Int images with floating point gain not displayed properlyhttps://issues.qgis.org/issues/11573?journal_id=579432014-12-04T04:43:08ZGiovanni Manghigiovanni.manghi@gmail.com
<ul></ul><p>Matthew Hanson wrote:</p>
<blockquote>
<p>I would like to request that the "feature" of applying Gain and Offset be reverted until this bug is fix. As it stands QGIS is completely unusable if you store floating point images as Int16 to save space (a very common thing to do for storing indices such as NDVI). We have had to peg our QGIS at 2.2.</p>
</blockquote>
<p>I'm not sure I completely understand the issue, anyway I suggest you to raise the problem in the developers mailing list, where there is a much larger "audience".</p> QGIS Application - Bug report #11573: Int images with floating point gain not displayed properlyhttps://issues.qgis.org/issues/11573?journal_id=598242015-03-05T19:23:38ZNyall Dawson
<ul><li><strong>Status</strong> changed from <i>Feedback</i> to <i>Closed</i></li></ul><p>Fixed in changeset <a class="changeset" href="https://issues.qgis.org/projects/qgis/repository/revisions/914ecc9c0980012b27b15ce5616cf5541da66f55" title="Fix incorrect data type for GDAL layers with gain/offset (fix #11573) Test was incorrectly check...">914ecc9c0980012b27b15ce5616cf5541da66f55</a>.</p>