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

[Radim Blazek]

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?

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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