Help with Plant Health Export Post Processing

Hi folks,

Novice in map manipulation here. So I’ve got WebODM working great and producing some fantastic looking outputs with Plant Health that should be useful. When I hit the export button, all the pretty colors are lost and I have something that looks grey and boring. What do I need to do with the exported GeoTIFF to restore the RdYlGn color bands? I’ve got QGIS installed but no clue how to use it. Yet.

Hi Dave,

Edit: It’s been a long day and somehow I read that you were looking to colorize a DEM. I’m not certain if hillside shading will help with multispectral, but I’ll leave the link below in case someone else is looking for the similar problem when exporting a DEM to geotif and trying to view it in QGIS or other GIS applications.

I belive this is the answer you’re looking for. For DEM GeoTifs, you’ll need to apply hillside shading. Here’s a tutorial that should help you out and get you on your way.

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You need to set up a Renderer in QGIS. The “gray” TIFF file is exactly what you need. The values (0-255 typically) represent the value of the phenomena being mapped. Sometimes elevation in meters, sometimes reflectance in a particular band, sometimes a derived metric like Plant Health.

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Edit the layer’s symbology, then choose Singleband pseudocolor, set your min/max (optional), then hit classify and then Apply to get started. You may want to change the colorramp from Linear to another type, or change the classification method, number of classes, min/max, etc. as necessary.

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So the method used for colorizing a DEM is similar for multspectral then?

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Excellent, thanks guys - exactly what I was after!

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Eeeeeh… Depends on what you’re visualizing. If you’re just interested in the distribution of values in a single band of a multispectral dataset (How much Near-Infrared Reflectance did we have?), then yeah, you use the Single-band Pseudocolor Renderer just like you would for a DEM.

If you’re looking at representing something else (like False-Color Infrared), then no, you’ll need to set up a different Renderer and choose the bands accordingly, possibly correct the ranges per-band and apply some other post-processing (gamma stretch, etc.)

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Part of a future improvement: https://github.com/OpenDroneMap/WebODM/issues/886

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Also just opened a fund to implement this: Let's fund the export of maps and elevation models in plain TIFF or JPG!

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