[EXTERNAL] [rasterio] Applying Color Ramp to Single-Band Grayscale Images

Hare, Trent M

  Not sure about using rasterio, but have you tried gdaldem using "color-relief"?

shows creating a colorized image and adding hillshade (hillshade step not needed here):


From: main@rasterio.groups.io <main@rasterio.groups.io> on behalf of nathan.raley via Groups.Io <nathan.raley@...>
Sent: Tuesday, March 24, 2020 3:12 PM
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Subject: [EXTERNAL] [rasterio] Applying Color Ramp to Single-Band Grayscale Images
Does anyone have any methods of applying a color ramp to a grayscale image? 

I have a NDVI calculated image I am trying to apply color ramp for the decimal based value ranges, but have no idea how to accomplish this.  I was wandering if this was possible via any of the rasterio libraries, and, if so, how would one go about accomplishing this?  I have other band based calculations I'd like to attempt, but until I can figure out how to apply the color ramps, I am at a stand still.



Thanks Trent,

I have looked into that, but the part of using the colormap.txt portion still is a bit confusing.  I haven't been able to find sufficient documentation on how to create that file to apply the color, or a ramp between two color ranges, for the values.  I did find a method in the python wrapper library for gdal that supported creating a color ramp for ranges using a specified color; however, that only supported whole number values and not the float based values you get from the NDVI image.


Actually, that second link looked like he had the format where it was using decimal based values, that might work.  I'll give it a try.  Thanks!