[Qgis-user] R: Symbolizing a discrete or a boolean raster

[Enrico Fiore]

Hi,
I think that the solution is in the QGIS documentation, that you can read here: http://docs.qgis.org/2.14/en/docs/user_manual/working_with_raster/raster_properties.html#band-rendering
you have to use Singleband pseudocolor and set color interpolation to Discrete.

Enrico





----Messaggio originale----

Da: "Stéphane Henriod" <s at henriod.info>

Data: 09/01/2017 6.30

A: "qgis-user"<qgis-user at lists.osgeo.org>

Ogg: [Qgis-user] Symbolizing a discrete or a boolean raster



Dear all
As much as I love QGIS and use it in my everyday life, there is one feature that I find particularly annoying: the styling of discrete rasters.
Basically, if I have a raster layer consisting of discrete landcover values (1: water, 2: forest, 3: built-up), it seems that there is no easy way to style it. QGIS will assume that the data is continuous and basically interpolate the color between each value, which leads to the following issues:
Let's say I want to display only water and built-up (values 1 and 3), water in blue and built-up in grey. QGIS will still display the forests, using a color somewhere "between" blue and grey. My only left option is to process the raster to actually replace all the 2 with NoData, which is highly unpractical...
Same if I have a boolean raster (only 0 and 1 values). QGIS will by default make a color ramp from 0 to 0.9999.
Also, the whole rather feels like a work-around for a missing feature.
I dream of a feature similar to this one from ArcGIS: http://resources.arcgis.com/en/help/main/10.1/index.html#/representing_unique_categories_such_as_land_use/009t00000074000000/ where all unique values are styled independently and where I can easily skip the values I don't want to see on my map.
I asked a question here:http://gis.stackexchange.com/questions/194116/qgis-style-a-discrete-raster
and opened a ticket here:http://hub.qgis.org/issues/14845
But none has gotten lots of attention yet... Am I the only one to be annoyed by this? If no, please raise your hand and let's try to get some momentum and see how to push this feature forward!
Thanks a lot in advance!
Cheers
Stéphane

-- 
Stéphane HenriodCIM-Expert for GIS and Green Economy Statistics
Национальный статистический комитет Кыргызской РеспубликиКыргыз Республикасынын Улуттук статистика комитетиNational Statistical Committee of the Kyrgyz Republic
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