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

[Benoit de Cabissole]

 Hi Tim,

I've just sent you some data to your linfiniti mailbox.

Thanks to follow up,
Benoit


On 01/11/2010 16:50, Tim Sutton wrote:
> Hi
>
>
> On Sun, Oct 31, 2010 at 10:54 AM, Benoit de Cabissole
> <benoit at exigesa.com> wrote:
>>  Hi Tim,
>>
>> Many thanks for fixing the problems [14381, 14387 & 14425]!
>>
>> But there is now another one popping up:
>>
>> When the data values in an one-band raster are real numbers and are
>> negative/positive or are greater than 255 (?) the histogram curve does
>> not display. The x- and y-axis correctly show the range of values but no
>> curve is displayed. Furthermore, if data values are positive and
>> negative, the histogram curve stops at 0: no curve over the negative values.
>>
>>
>> It also looks like the number of bins is too small when the data range
>> is small. I've got a raster with "real number" values between 0 and 5.
>> The number of bins on that raster is only 6. This is far too coarse to
>> be of any use.
>>
>> Do I open a ticket for those problems?
>
> Do you have a small sample dataset I can use to replicate the issue?
>
> Regards
>
> Tim
>
>> Cheers,
>> Benoit
>>
>>
>>
>>
>> On 18/10/2010 09:29, Benoit de Cabissole wrote:
>>>  Hi Tim,
>>>
>>> Just after upgrading to release 14390 the histogram function works like
>>> a charm when I open *for the first time* the raster properties window.
>>> Thank you!
>>>
>>> But, if I close the raster property window while in the histogram tab
>>> and try to re-open it, QGIS crashes!
>>> In fact I cannot open any raster properties window after that without
>>> having QGIS crash...
>>> I've edited the 'row' value in the RasterLayerProperties in the registry
>>> to set it to 1 (from 6) and I can again use QGIS normally.
>>> So it seems that the raster properties window bombs out QGIS if it opens
>>> in the histogram tab (row=6).
>>>
>>> Can you reproduce this behaviour in Linux/Mac/Other win?
>>>
>>> I'm on WindowsXP in OSGeo4W.
>>>
>>> One comment: the stats are computed each time the histogram tab is
>>> opened. For large raster it takes a long time to compute the histogram.
>>> Would it be best to save the histogram somewhere and reuse it?
>>>
>>> Cheers,
>>> Benoit
>>>
>>>
>>>
>>> On 17/10/2010 09:23, Tim Sutton wrote:
>>>> Hi
>>>>
>>>> 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?
>>>>>
>>>> This should be fixed now as of r14387.
>>>>
>>>> Regards
>>>>
>>>> Tim
>>>>
>>> _______________________________________________
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>>> Qgis-developer at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>>
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>
>