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Main question: How do I manually edit raster layers on QGIS 3.0?

Some context: I georeferenced Google Earth high resolution downloads on to QGIS, and was looking to do image classification for a study on urban areas. Everything I read suggested using ORFEO Toolbox, but my QGIS 2.18, which was supposed to come pre-equipped with ORFEO never seemed to work for me and QGIS 3.0 is incompatible with ORFEO. Then I tried the Semi-automatic Classification Plug-in (SCP) that is also recommended, but it doesn't seem to like my GE screen grabs because they only have 3 bands (everything I read says it should be 4 or more bands). Then I thought I might try just editing the pixels manually so that one color meant built-up, another vegetation, etc., which would take forever, but at least would be more straight forward- but I can't figure out how to edit pixels on QGIS (I read that the Serval Plugin would work, but it is incompatible with QGIS 3.0 and before going back to QGIS 2.18, I wanted to see if there were any other recommendations). Ultimately, I'd like to create a vector layer with an attribute table that has the %age of land-type per polygon (land-type percentages coming from the raster that I create from the georeferenced GE image).

I am using a MacBook Air.

  • Have you tried using the standalone versions of Orfeo? – JoshC Apr 7 '18 at 23:13
  • @JoshC, I haven't - I was under the impression I'd have to do everything on command line and then I could view the resulting layers on Monteverdi, but maybe this is not the case? (Currently reading some documentation) Do you have any particular resources you would point towards to see if it would work for my purposes? – Natalia Piland Apr 7 '18 at 23:29
  • You could use the raster calculator to create a categorized version of the google earth raster. – csk Apr 9 '18 at 17:50
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Since you were looking for editing raster pixels manually the accepted answer here describes what you were probably looking for. See if it solves your problem.

  • Great that you have provided an answer. But for others to make sense of what you are proposing, please elaborate a bit on what you suggest. May be any of these could help, why should they help? What are one, two and three meaning here? How are they answering Natalia's question? – Chau Apr 8 '18 at 11:32

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