[Qgis-developer] Symbolizing a discrete or a boolean raster

[Stéphane Henriod]

One last message for today (sorry for spamming!)

It seems that this feature would actually be wished by "many" people (see
the ticket and the talks on user-). I just gave a try to 2.99-nightly and,
as far as I can see, nothing has been done in this direction (yet?).

I am wondering if there are massive challenges that I am overlooking or if
this could be implemented quite easily. In any case, do you think this is a
request that can be taken on to 3.0?

Thanks a lot to all the devs here... I feel quite bad for asking for a new
feature while not having the competences to contribute a tiny bit to its
development but I really feel this is one of the few major missing features
in QGIS right now (and will be happy to help on the feature requirements,
the tests, etc.).

All the best!

Stéphane


Le mercredi 11 janvier 2017, Stéphane Henriod <stephanebek at gmail.com> a
écrit :

> Hi again
>
> it seems that the requirements are related (although not 100% similar) to
> this other open (and assigned) ticket: http://hub.qgis.org/issues/14449
>
> I really hope to see this very needed feature in a coming version of QGIS
> and happy to help wherever I can!
>
> Cheers
>
> Stéphane
>
>
> Le mardi 10 janvier 2017, Stéphane Henriod <stephanebek at gmail.com
> <javascript:_e(%7B%7D,'cvml','stephanebek at gmail.com');>> a écrit :
>
>> Hi
>>
>> let me move here a request that has been shortly discussed on the
>> user-mailing list:
>> http://lists.osgeo.org/pipermail/qgis-user/2017-January/038793.html
>> http://lists.osgeo.org/pipermail/qgis-user/2017-January/038795.html
>> http://lists.osgeo.org/pipermail/qgis-user/2017-January/038801.html
>>
>> and for which a ticket is open:
>> http://hub.qgis.org/issues/14845
>>
>> I was said that some work has been done in this direction for 3.0 but I
>> don't know if it completely covers the feature request
>>
>> ----------------------
>>
>> When styling a discrete or boolean raster, there seems to be no direct
>> method, only a few workarounds. The feature I dream of would do the
>> following:
>>
>>    - A new render type "Discrete raster"
>>    - One button allows to fetch all unique values form the raster (with
>>    a warning message if there are more than XXX unique values)
>>    - A color ramp is applied by default
>>    - I can multi-select values and apply them the same style and / or
>>    the same label
>>    - I can remove values. The pixels with those values will simply not
>>    be displayed
>>    - I can save my color map and load an existing color map
>>
>> So pretty much like the ArcGIS implementation:
>> http://resources.arcgis.com/en/help/main/10.1/index.html#/re
>> presenting_unique_categories_such_as_land_use/009t00000074000000/
>>
>> The current limitations I see (in 2.14):
>>
>>    - The discrete values must be entered manually, which is a pain for a
>>    raster with many unique values (or if I don't know in advance what all
>>    values are)
>>    - If I click on *Classify*, QGIS will choose X values (based on the
>>    number of classes and the classification method (continuous or equal
>>    interval)), which no longer match the "exact" values of my raster. It
>>    doesn't really make sense to classify a discrete rendering
>>    - Although it is currently possible to style discrete rasters, the
>>    procedure is not really intuitive for beginners
>>
>> ----------------------
>>
>> Is this a feature that is envisioned for 3.0? Is there anything I can do
>> to support it? (except coding it myself, since I don't have the skills for
>> that...)
>>
>> Thanks a lot in advance
>>
>> Cheers
>>
>> Stéphane
>>
>>
>
> --
>
> “When you travel, remember that a foreign country is not designed to make
> you comfortable. It is designed to make its own people comfortable." --
> Clifton Fadiman
>
>

-- 

“When you travel, remember that a foreign country is not designed to make
you comfortable. It is designed to make its own people comfortable." --
Clifton Fadiman
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