discussion / Remote Sensing & GIS  / 14 March 2018

Drone Mapping for Algal Blooms?

Hi everyone!

I am new to the drone world, but I am very curious if anyone has come across any work involving the mapping of algal blooms using drones? I can imagine the Floating Algal Index would be the best option, but I don't think I have access to a multispectral camera that has SWIR, NIR, and Red. 

Does anyone know if NDVI would work? Also, does anyone have experience mapping water bodies with drones? I hear it can be a bit of a challenge due to sun glint and ripples.

 

Thank you!

Chippie Kislik

Graduate Student, UC Berkeley




Hi Chippie,

I think you're probably on the right track with NDVI. There are UAV systems that will do this e.g. the Parrot Sequoia springsto mind, though I'm sure there will also be cheaper alternatives if you're prepared to hunt around and/or build your own platform. Just a note to say that Rio Button from South Africa is going to be presenting on 'Using a Remotely Operated Vehicle to explore offshore ichthyofauna and habitat' at the Student Conference on Conservation Science here in Cambridge in a couple of weeks. It might be worth getting in touch with her, or even better inviting her to the forum to discuss!

Remember to check out our Drones for GIS - Best Practice document over in the Drones group, and let us know if you'd like to contribute.

Thom

Fantastic, thank you, Thom! I will perhaps also pose this question in the Drone group.

All the best,

Chippie

if you are using NDVI with nir band (so, red and nir) the NDVI camera won't work for you - NIR does not penetrate water (it's often what you use to create a water mask), and red only minimally. You need blue and green bands!

This is why most studies use MERIS, MODIS, SeaWiFS -if you actually want to quantify chlorophyll. There is a lot of literature that explains what wavelengths work best https://www.sciencedirect.com/science/article/pii/S0079661114000020 though satellites have more spectral resolution in this regards, and it also depends on what kind of water (case I or II or freshwater). anyway, if it's something you can see with the naked eye, then a normal camera will do. Also, the parrots are super expensive - I find it kindof risky to have a camera that costs more than the drone. I recommend the Mapir Survey cameras come in a number of configurations and run only for 400USD, and some are even on sale at mapir. and the new ones have integrated GPS! 

https://www.mapir.camera/

Hi, I'm a drone fanatic and have a random question. The systems you're using to map the blooms currently... can they see down into water from above? Or do we need to design you a drone that can land on the water. Example: fish finders need to have their sensor down in the water for them to work, the fish finder drone would HAVE to land or lower the sensor down into the water.