Public Lab Research note

NDVI test in Lima Peru

by warren | December 24, 2010 14:39 24 Dec 14:39 | #35 | #35

We've been talking about NDVI imaging and i finally gave it a try, using Photoshop.

4 Comments

  
Comment Author Profile Picture adam-griffith commented over 13 years ago

What nanometer filter did you use for the middle image?

Also, here is a great youtube vid on how to make NDVI images in GRASS GIS: https://www.youtube.com/watch?v=IFTh3UuMSHw&feature=related

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Comment Author Profile Picture warren commented over 13 years ago

Sorry i answered you in the mailing list. I should install something to send an email alert if someone comments on your stuff, i guess.

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Comment Author Profile Picture warren commented almost 6 years ago

A long time later -- here's an attempt to use Image Sequencer to do this:

https://publiclab.github.io/image-sequencer/examples/#steps=import-image,blend,ndvi,colormap

This isn't quite working yet, but here are the separated images:

Visible:

san-martin-visible.jpg

Infrared:

san-martin-infrared.jpg

And the original NDVI from the above image:

san-martin-ndvi.jpg

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Comment Author Profile Picture warren commented almost 6 years ago

OK - now able to do this by adding infrared first, then visible, then blending, then ndvi (red filter):

san-martin-is-ndvi.jpg

It's a little dimmer because I think we mapped -1..1 NDVI values to 0..100% brightness values.

Then colormapping:

san-martin-is-colormap.jpg

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