A Napa Valley company that has been taking aerial imaging of vineyards to new technological heights for a decade and a half has formed a strategic partnership with grapegrower-oriented startup makers and operators of unmanned aerial vehicles, often called drones.
It’s the second significant foray in recent months that brings the fast-growing field of agricultural drones to the North Coast.
The deal pairs image processing by Angwin-based Scientific Aerial Imaging Inc., better known as VineView (vineview.com), with drones built by Halifax, Nova Scotia-based SkySquirrel Technologies (skysquirrel.ca) then marketed and flown by Napa Valley’s Hawk Aerial (hawkaerial.com). Hawk Aerial has plans for piloting drones for vineyard operators or selling drones that can be piloted largely autonomously by designating a flight path on a virtual map of the vineyard.
“We think that is the most exciting part, that vineyard operators can fly as often as they want and send images to VineView for processing,” said Bryan Soderblom, CFI, CFII, MEI, VineView’s lead pilot and marketing director.
Five-employee VineView bases its sensor-festooned, full-sized single-engine planes at Angwin Airport–Parrett Field atop Howell Mountain on the eastern slopes of the valley. VineView has been working with SkySquirrel for two years to calibrate the drone systems it builds and analyze its clients’ data.
SkySquirrel also has outposts in Switzerland and next to VineView at the Angwin airport. VineView’s arrangement with Hawk, a Napa Valley-based operator and marketer of SkySquirrel’s drones, developed over the past few months. The deal allows VineView to work with more clients who think having people in planes taking images of crops is too expensive, Soderblom said.
“We found drones most-efficient for smaller- to medium-sized vineyards — less than 100 acres,” he said. “Above that, it’s more efficient with an airplane.”
The aerial robots VineView works with can capture images at a rate of 1 acre per minute, covering 20–25 acres on a battery charge. By comparison, VineView’s plane-mounted sensors grab shots over 100 acres of vineyard might take about 10 seconds. Commercial drones have limited operating altitude under 120 feet by new Federal Aviation Administration guidelines, but that results in much higher resolution for crop imaging, Soderblom said.
“There is still market out there for airplane-based imaging, but I think drones will increase in use for smaller vineyards,” Soderblom said. “As battery life increases, drones will become more-efficient for larger vineyards as well.”
Depending on what imaging is needed and other parameters, the cost of airplane-based imaging and analysis of the hyperspectral images can be $10–$15 an acre for enhanced vigor index, or EVI, mapping of vine health up to $35–$40 an acre for RedLeafMap to show which vines are stressed by leafroll and red blotch diseases.
The EVI service, and higher-resolution PureCanopy EVI, builds on the normalized difference vegetation index, or NDVI, developed in 1992 by research at Robert Mondavi Winery. The difference is that EVI imaging isn’t dependent on the time of day the image is captured, soil variations or shadows for comparison of vine conditions over time.
Other VineView imaging services are mapping vineyards by infrared, which helps in classifying vines for EVI analysis, and to show how vines are dealing with stress from lack of water. Modern winemaking has tended to varying forms of water stress to coax more vine resources into the grapes, but too much stress could be counterproductive.