[Qgis-developer] No data value in raster transparency list

[Etienne Tourigny]

On Thu, Aug 23, 2012 at 9:30 AM, Radim Blazek <radim.blazek at gmail.com> wrote:
> On Thu, Aug 23, 2012 at 2:08 PM, Etienne Tourigny
> <etourigny.dev at gmail.com> wrote:
>> I also find it puzzling that the data type changes (say from byte to
>> int). I understand that it is needed to have a nodata value when none
>> is given, but it would be nice to hide this from the user as well.
>
> User should not know about it. srcDataType() is used in metadata. Is
> there another place where user can see the internal type used?

osrry, you are right - the only thing that shows up in the properties
is the nodata value, type remains the same
>
> More challenging issue is how to handle data types in analytical tools
> (map calculator for example) reading from data providers. For example
> int+int should be int. The tool should use srcDataType(), but it would
> not work well if another interface (which changes data type) was
> plugged after the provider.
>
> Radim
>
>> Etienne
>>
>> On Thu, Aug 23, 2012 at 9:05 AM, Radim Blazek <radim.blazek at gmail.com> wrote:
>>> On Wed, Aug 22, 2012 at 6:13 PM, Etienne Tourigny
>>> <etourigny.dev at gmail.com> wrote:
>>>> On Wed, Aug 22, 2012 at 1:11 PM, Bob and Deb <bobdebm at gmail.com> wrote:
>>>>> I've seen nodata with huge float32 values.  Unfortunately they are rendered
>>>>> in qgis and I can not make them transparent by adding the value to the
>>>>> transparency list.
>>>>
>>>> that's because gdal provider chooses a nodata value that is out of the
>>>> range of "real" values, when file does not contain a nodata value.
>>>
>>> Yes. I agree that it is confusing for users. I would like to hide from
>>> users those internal nodata values, removing it from the transparency
>>> list is one step.
>>>
>>> Radim
>>>
>>>>> On Aug 22, 2012 8:56 AM, "Giovanni Manghi" <giovanni.manghi at faunalia.pt>
>>>>> wrote:
>>>>>>
>>>>>> It isn't the only odd thing/bug with nulls and transparency. For example
>>>>>> not always nulls are rendered transparent and when you try to add them to
>>>>>> the transparency list the entry is added as 0 instead.
>>>>>>
>>>>>> On Aug 22, 2012 4:49 PM, "Radim Blazek" <radim.blazek at gmail.com> wrote:
>>>>>> >
>>>>>> > Hi,
>>>>>> > does anybody know why raster no data value is automatically added to
>>>>>> > transparency list in properties dialog? It makes no sense IMO. No data
>>>>>> > values are always rendered as transparent, no need to define them also
>>>>>> > in transparent list.
>>>>>> >
>>>>>> > Radim
>>>>>> > _______________________________________________
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>>>>>> > Qgis-developer at lists.osgeo.org
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>>>>>>
>>>>>>
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>>>>>
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