Public Lab Research note

Mapping the Nature Center

by eustatic | October 24, 2014 02:01 24 Oct 02:01 | #11298 | #11298

What I want to do

As part of the Nature Center map, Lauren Sullivan, Tim, and Scott Eustis joined Amy Legaux of Audubon Nature Center and we mapped the nature center trail by balloon.

Amy Gave us a map of what has been done where for reference.

Scott took pole selfies with a RGB camera.

Here's the imagery from the balloon mapping.

My attempt and results

Great weather for the balloon.

Images had great coverage. we are unsure how to undistort the image to get a map from the infragram point and shoot, though.

Questions and next steps

need to color match the levels smooth them out.

then stevie wants us to use infragram, rather than fastiegram it in GIMP.

fastiegram includes

Lens Distortion == -34
Levels == move center up to heighten contrast
Channels == color components, channel mixer, Switch B and R
Hue and Saturation == up both 20.

other infragrams include

Why I'm interested

This is part of EPA Urban Water grant. Molly and stevie also made maps tonight.


I made an NDVI in infragram but now i can't save it. I think this shows red where the tallow are, since the tallow are the trees which are undergoing senescence earlier in the year.

another one

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Those are nice Mobius photos. It should be possible to correct for the wide angle distortion, but you can't correct for the fact that such a wide angle lens captures the tops of the trees near the center of the frame but the sides of the trees near the edges. So stitching Mobius photos into a map or panorama will always be tricky.

FastieGram CIR and NDVI:

The wide angle lens also makes NDVI tricky to interpret because sun angle influences color balance so NDVI values on one side of the image might not be comparable with those on the other side. That's less of a problem on cloudy days.

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Scott, I forgot about teaching you how to correct distortion in PhotoShop. I'm not sure how to use any of the open-source image editing software. Next time we map using this camera, we need to then schedule a photo-editing time (we can use the two computers I have at home with Creative Suite).

Would it be valuable to anyone else to create an RGB camera with a 50mm equivalent lens to reduce distortion?

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Lauren, i have a NIR cam that is a a2300, it should be closer to 50 mm

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