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Is there a plugin or function in QGIS that allows for RGB raster color adjustments to enhance visibility of specific features captured on a map?

Example:

I'd like to enhance contrast and saturation of high resolution orthomosaic to make drainage system (below the soil) more visible and easier to vectorize. Output raster is less saturated (but better color balanced) than original photos from which was made so it makes harder to spot all lines.

It can be obviously done in i.e. Photoshop but due to file size limitations and potential loss of georeferencing I prefer to use QGIS for that.

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If I got it right, you don't need any plugins. Just play with the stretching of the bands. There are plenty of options. This is a screen of QGIS 2.18

enter image description here

You can even highlight specific features, filling the Min-Max values of each band according to their range. Of course you could create some training areas in your features and do some kind of image classification, but if you just want to enhance a bit these areas just navigate above them with the value tool and fill the Min-Max values accordingly.

Here's an example of this procedure for fast stretching of features:

enter image description here

  • Thanks Albert! I've always played with properties of dsm-s color ramps, never RGB ones so I assumed that it must be more complicated :) – proteus Apr 20 '18 at 10:26
  • Glad it helped :) Actually, there's even a faster way. Zoom in to your feature and load the actual values using the "clip extend to canvas". It will grab the Min-Max values of the current extent which will be optimized for whatever feature you have there. – Albert Apr 20 '18 at 10:59
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    And if you use a recent version of QGIS, you can make it update that in realtime as you move the canvas around. – bugmenot123 Apr 20 '18 at 11:31
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    @bugmenot123 Nice! One less thing to miss from ArcGIS (DRA image analysis), not that many left... – Albert Apr 20 '18 at 11:40

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