Hi Stéphane, 2017-01-10 4:02 GMT+01:00 Stéphane Henriod <s...@henriod.info>:
> Hi Chris > > this is very nice! I indeed didn't know this trick and will certainly use > it again in the future! > > However... :-) > > I am currently teaching QGIS to beginners and this for sure is not an > appropriate method for them (especially in the case you have to generate > the symbology file through a script)! > > Since the user can style continuous rasters with some "button-clicking", I > believe the same option should be available for discrete rasters as well. > > I am thus wondering if anyone else than me sees it as a priority for QGIS? > If yes, how to motivate the developers to take it for the next release and > / or how much would such a development cost? (I unfortunately don't have > the competences to do it myself) > > There have been some work done in the raster properties dialog in the upcoming 3.0. I don't know if your concern was covered though. If you want, you can move the question to the developer's list <http://qgis.org/en/site/getinvolved/mailinglists.html#qgis-developers-list> and discuss whether/how this can be implemented (and its requirements). Regards, Harrissou Thanks again and cheers! > > Stéphane > > > Le mardi 10 janvier 2017, Chris House <house...@gmail.com> a écrit : > >> Hi Stéphane, >> >> I don't know if this is what you are looking for or not but I have a >> method of classifying rasters by color based on a set (standard) colors. I >> created a spreadsheet that has several required columns, value, red, green, >> blue...and you can have an optional field for a display value. So say >> value 1 is water you can use that last column to name that value so that in >> the QGIS layer tree and in legend it says Water instead of value 1. >> >> save the spreadsheet as a csv and change the extension to .txt instead of >> .csv. >> >> I then go into the symbology section of the raster choose singleband >> pseudocolor. Use the folder to browse to your text file and click add. >> There is a format for this text file. It is below. If you need me to >> email it I will do that in direct email. >> >> # QGIS Generated Color Map Export File >> INTERPOLATION:EXACT >> -9999,0,0,0,255,NoData >> 0,176,176,176,255,Non-Forested >> 15,234,255,191,255,10 <= CC < 20 >> 25,187,230,149,255,20 <= CC < 30 >> 35,140,201,109,255,30 <= CC < 40 >> 45,98,176,74,255,40 <= CC < 50 >> 55,59,153,43,255,50 <= CC < 60 >> 65,0,128,0,255,60 <= CC < 70 >> 75,15,92,11,255,70 <= CC < 80 >> 85,17,61,12,255,80 <= CC < 90 >> 95,16,36,12,255,90 <= CC <= 100 >> >> In my example if I don't assign a value it gets ignored by QGIS. If you >> are wondering how to assign unique colors to say 200 unique values...just >> script it. I have done this and as long as you have the number of unique >> values you want and to make them unique in the script it works. >> >> I hope this helps. I know it isn't a "button" but to be honest I like >> this better. If you already knew this...well then maybe it will help >> someone out in the future. >> >> --Chris >> >> On Mon, Jan 9, 2017 at 3:00 PM, <qgis-user-requ...@lists.osgeo.org> >> wrote: >> >>> Send Qgis-user mailing list submissions to >>> qgis-user@lists.osgeo.org >>> >>> To subscribe or unsubscribe via the World Wide Web, visit >>> http://lists.osgeo.org/mailman/listinfo/qgis-user >>> or, via email, send a message with subject or body 'help' to >>> qgis-user-requ...@lists.osgeo.org >>> >>> You can reach the person managing the list at >>> qgis-user-ow...@lists.osgeo.org >>> >>> When replying, please edit your Subject line so it is more specific >>> than "Re: Contents of Qgis-user digest..." >>> >>> >>> Today's Topics: >>> >>> 1. Re: Symbolizing a discrete or a boolean raster (Stéphane Henriod) >>> >>> >>> ---------------------------------------------------------------------- >>> >>> Message: 1 >>> Date: Mon, 9 Jan 2017 23:07:36 +0600 >>> From: Stéphane Henriod <s...@henriod.info> >>> To: Enrico Fiore <enricofi...@libero.it> >>> Cc: qgis-user <qgis-user@lists.osgeo.org> >>> Subject: Re: [Qgis-user] Symbolizing a discrete or a boolean raster >>> Message-ID: >>> <cak6pvbxurm_e7drp+8sp9ampuux0+cn3gvxlpnjohhno85o...@mail.gm >>> ail.com> >>> Content-Type: text/plain; charset="utf-8" >>> >>> Hi >>> >>> thanks for following up! >>> >>> It actually does part of the job! >>> >>> Using *Color interpretation: Exact*, I can indeed input the exact values >>> I >>> want to display (1,5 and 10) and all other pixels are hidden. >>> >>> HOWEVER, >>> >>> this still feels like a workaround: >>> >>> - In the case of a discrete raster with many (> 50) unique values, I >>> do >>> not want to input all of them manually >>> - In some cases, I do not know in advance all the unique values of my >>> raster >>> - 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 >>> >>> So I would say, we still need a render type "discrete raster" which >>> offers >>> the function to "retrieve all unique values" (and automatically apply a >>> discrete color ramp) >>> >>> Attached a (fake) test dataset. >>> >>> Thanks and cheers >>> >>> Stéphane >>> >>> >>> Le lundi 9 janvier 2017, Enrico Fiore <enricofi...@libero.it> a écrit : >>> >>> > Hi, >>> > Sorry I can't do test, but if you use exact in color interpolation >>> > parameter? >>> > >>> > Cheers >>> > >>> > Enrico >>> >>> >>> Le lundi 9 janvier 2017, Stéphane Henriod <s...@henriod.info> a écrit : >>> >>> > Hi >>> > >>> > unfortunately this is doing quite something different! >>> > >>> > If I have a raster with 10 Landcover classes (1,2,3,4,5,6,7,8,9,10) >>> and I >>> > want to display only 1,5 and 10, using *Discrete *(1: red, 5: yellow, >>> 10: >>> > blue) the following will happen: >>> > >>> > All pixels between 1 and 4 will be red >>> > All pixels between 5 and 9 will be yellow >>> > All pixels with 10 will be blue >>> > >>> > In this sense, the pixels are indeed not interpolated, but this still >>> is >>> > not the behavior I am expecting when styling discrete rasters. >>> > >>> > A "style discrete raster" function should offer the following: >>> > >>> > - Automatically recover all unique values from the raster >>> > - Only display the pixels to which the user has explicitly assigned >>> a >>> > color >>> > >>> > But thanks for your hint, this can be helpful in other cases! >>> > >>> > Cheers >>> > >>> > Stéphane >>> > >>> > >>> > Le lundi 9 janvier 2017, Enrico Fiore <enricofi...@libero.it >>> > <javascript:_e(%7B%7D,'cvml','enricofi...@libero.it');>> a écrit : >>> > >>> >> 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_r >>> >> aster/raster_properties.html#band-rendering >>> >> you have to use *Singleband pseudocolor *and set color interpolation >>> to >>> >> Discrete. >>> >> >>> >> Enrico >>> >> >>> >> >>> >> ----Messaggio originale---- >>> >> Da: "Stéphane Henriod" <s...@henriod.info> >>> >> Data: 09/01/2017 6.30 >>> >> A: "qgis-user"<qgis-user@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/009t00 >>> 000074000000/ >>> >> 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-d >>> >> iscrete-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 Henriod >>> CIM-Expert for GIS and Green Economy Statistics >>> >>> Национальный статистический комитет Кыргызской Республики >>> Кыргыз Республикасынын Улуттук статистика комитети >>> National Statistical Committee of the Kyrgyz Republic >>> >>> 374 Фрунзе ул. / Frunze str. >>> 720033 Бишкек / Bishkek >>> >>> T +996 778 46 99 02 (KG) >>> T +49 176 280 11 050 <+49%20176%2028011050> (DE) >>> E s...@henriod.info >>> W http://www.stat.kg >>> W3W: nightfall.into.bucket >>> <https://map.what3words.com/nightfall.into.bucket> // >>> запас.союз.дружный >>> <https://map.what3words.com/запас.союз.дружный> >>> -------------- next part -------------- >>> An HTML attachment was scrubbed... >>> URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/2017 >>> 0109/985fd14c/attachment-0001.html> >>> -------------- next part -------------- >>> A non-text attachment was scrubbed... >>> Name: landcover.zip >>> Type: application/zip >>> Size: 2151 bytes >>> Desc: not available >>> URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/2017 >>> 0109/985fd14c/attachment-0001.zip> >>> >>> ------------------------------ >>> >>> Subject: Digest Footer >>> >>> _______________________________________________ >>> Qgis-user mailing list >>> Qgis-user@lists.osgeo.org >>> List info: http://lists.osgeo.org/mailman/listinfo/qgis-user >>> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user >>> >>> ------------------------------ >>> >>> End of Qgis-user Digest, Vol 131, Issue 13 >>> ****************************************** >>> >> >> > > -- > Stéphane Henriod > CIM-Expert for GIS and Green Economy Statistics > > Национальный статистический комитет Кыргызской Республики > Кыргыз Республикасынын Улуттук статистика комитети > National Statistical Committee of the Kyrgyz Republic > > 374 Фрунзе ул. / Frunze str. > 720033 Бишкек / Bishkek > > T +996 778 46 99 02 (KG) > T +49 176 280 11 050 <+49%20176%2028011050> (DE) > E s...@henriod.info > W http://www.stat.kg > W3W: nightfall.into.bucket > <https://map.what3words.com/nightfall.into.bucket> // запас.союз.дружный > <https://map.what3words.com/запас.союз.дружный> > > > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: http://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user >
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