Category: Cameras

24 Sep 2018
Wheat multispec

Multispectral Data for Agriculture 2018

This year we have been working with a few local farms creating agricultural maps using drones to assess plant health and assist variable rate application of fertiliser, herbicide and pesticides. Using a modified Phantom 3 drone with the Parrot Sequoia multispectral camera we successfully performed dozens of missions this summer on a variety of crops. Some examples are shown below processed using Pix4D and the ATLAS platform from micasense.

Slug damage and another issue
Top: Wheat slug damage over winter. Bottom: Potatoes with some compaction lines and density variation.
Variation in results for NDVI and NDRE for potatoes.
Variation in results for NDVI and NDRE for potatoes.
Variation between NDVI and NDRE for wheat.
Variation between NDVI and NDRE for wheat.

One of the biggest problems we faced was presenting this data in a reliable GIS software. Most of the solutions currently lack features and only do one thing very well. For example ATLAS from Micasense is a far superior visualisation tool than Pix4D but it cannot create variable application zones for tractor shape files.

Towards the end of the season we purchased a Sentera 4K Double Multispec camera which has some interesting features over the current multispectral cameras on the market. In particular it has a higher resolution camera, is very compact with only two lenses and comes with a DJI compatible gimbal. This means more reliable stitching as the camera is always NADIR (looking straight down) where the P3 or fixed wings will capture slightly angled images depending on wind.

Over satellite imagery aerial imagery from drones provide far greater resolution. For example ESA Sentinel-2 has ground resolution down to 10m only and updates every 10 days which might or not be cloud free. A drone at 100m with the Parrot Sequoia camera provides GSD of 10cm and for the Sentera 4K 3.5cm, regardless of cloud cover.
There is certainly room for both approaches in farming, for analytical strength aerial imagery outperforms satellite. We look forward to sharing more imagery captured soon.