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QGIS 30.0 Windows 10 Pro I have a project to which I want to add a layer. The source for the new layer is a Tif image on which areas of infestation of a plant disease are shown in an orange colour. I want to include in the layer only these features, filtering out all other data. Is this possible?

Bill C
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  • Can you please share an image of the layer? Is it a classified raster with defined values or a refenced image? Depending on the input type your respective options are to select out the desired areas with raster calculator/styling or to run a supervised classify the image. – Cushen Mar 09 '23 at 22:14
  • You could also share the output of the "tiffinfo" console command (if installed) or the QGIS layer properties of the layer. Especially relevant is how many bands the file has got, and if it's a RGB TIF or not (as @Cushen mentioned) – til_b Mar 09 '23 at 22:40
  • Thanks for replies. I don't understand the process for adding an image to my question. – Bill C Mar 09 '23 at 23:00
  • Where do I find a clear explanation of how to add an image to my question as requested by Cushen? – Bill C Mar 09 '23 at 23:32
  • https://meta.stackoverflow.com/questions/344851/how-do-you-add-a-screenshot-image-to-your-stack-overflow-post – John Mar 09 '23 at 23:40
  • Thanks, John. I studied that question and it mentions an image button which I don't seem to have. – Bill C Mar 10 '23 at 00:02
  • @Bill C In the icons across the top of the window where you input text hold the mouse over each to see what it does. Looking at mine for an answer it is the icon to the left of numbers 1,2,3. with "mountains'. It also shows Ctrl + G to bring it up. You can save a screenshot as an image then add it. – John Mar 10 '23 at 00:24
  • Above the input window there is only one symbol which is a red flag for moderator attention - no other symbol. – Bill C Mar 10 '23 at 00:38
  • @John I was trying to add the image in the comment box, not the original Post. I then found the icons I needed but when I attempted to upload the 600KB image I got the message 'failed to upload image, an error occurred on the server'. – Bill C Mar 10 '23 at 01:45
  • @Cushen Converted the tif image to jpeg and it uploaded OK. – Bill C Mar 10 '23 at 02:42
  • @Cushen How do I determine if the raster is classified with defined values or referenced? I'm not familiar with those terms. – Bill C Mar 10 '23 at 04:34
  • You could use Raster calculator or the Magic Wand plugin, depending on the kind of data you have. See the solutions here for details: https://gis.stackexchange.com/q/417429/88814 – Babel Mar 12 '23 at 10:49

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