[Qgis-developer] Problems with Histogram tab in Raster properties

[Tim Sutton]

Hi Benoit

On Thu, Oct 14, 2010 at 9:51 AM, Benoit de Cabissole <benoit at exigesa.com> wrote:
>  Hi,
>
> A) In release 14370 the histogram tab of the raster properties window
> has a problem:
> The histogram is not displayed the second time the 'histogram tab' is
> clicked.
> E.g.:
> 1 - open the raster properties window
> 2 - click on the histogram tab
> 3 - histogram is computed and displayed
> 4 - click on any other tab
> 5 - click on the histogram tab again
> 6 - blank screen!!
>
> On WinXP - OSGeo4W dev installation
> Can someone replicate the problem?

Ok I could replicate that. Will fix.

>
>
>
> B) And keeping with the histogram, three comments/suggestions:
> - Could the NaN be excluded from the histogram?

According to the fine folks on #gdal (EvenR): "the pixels whose value
is nodata are excluded from the stats" - note that this is only the
nodata value considered by gdal - which isnt aware of any additional
nodata values you may have specified in the transparency tab.

> - Could the X-axis numbers reflect the actual colour values instead of a
> fixed 0-300 range?

Yes I am going to do this.

>   Note that the X-axis of the histogram is spread on colours values,
> thus the displayed X-axis numbers are meaningless

Right above should fix that.

> - Could it be possible to add a zoom function on the histogram?
>

I believe so - I will have a play and see how easy that will be.

Thanks for the feedback!

Regards

Tim



>
> Best regards,
> Benoit
>
>
>
> _______________________________________________
> Qgis-developer mailing list
> Qgis-developer at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>



-- 
Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
==============================================
Please do not email me off-list with technical
support questions. Using the lists will gain
more exposure for your issues and the knowledge
surrounding your issue will be shared with all.

Visit http://linfiniti.com to find out about:
 * QGIS programming and support services
 * Mapserver and PostGIS based hosting plans
 * FOSS Consulting Services
Skype: timlinux
Irc: timlinux on #qgis at freenode.net
==============================================