Weather conditions present an ongoing challenge for all aerial imagery providers, whether they are providing imagery from crewed aircraft, drones, or satellites. Imagery suppliers who fly crewed aircraft, such as TerrAvion, have an advantage over satellite providers in that we can design and adjust our flight plans to work around the weather. Still, weather, in addition to humidity, pollution, and haze, presents an ongoing challenge for our pilots in their mission to capture blemish-free imagery. To understand the challenges facing aerial imagery provider, you must remember one thing; what you see from the ground is not always indicative of what our pilots see from the sky.
To most imagery users, clouds represent the only real challenge to capturing aerial imagery. While there are many other challenges to overcome, clouds do present an ongoing struggle for pilots. For one, aerial imagery providers can’t control the weather. We are at the mercy of mother nature. When mother nature brings extended periods of poor weather, as it did throughout the first half of the 2019 growing season, we must work around it. Sometimes, we are simply unable to capture any imagery. Most users of aerial imagery understand this. What can be harder to explain for aerial providers is that what you see from the ground is not always indicative of what pilots see from the sky. Many times, as pilots are working to capture imagery, they are navigating around clouds that are not visible to someone standing on the ground. These clouds cause scattering and reduce the transmission of light, reducing the quality and value of imagery and in many cases making it useless. When planning flight operations for each season, TerrAvion considers and conducts in-depth analyses of historical data on cloud coverage in our service regions. On top of that, we give our pilots the flexibility to work around weather on the fly and plan to fly each field multiple times.
In addition to clouds between the plane and the ground obstructing image capture operations, clouds above the plane can negatively impact light quality. To account for this, in the near future, TerrAvion will be measuring the amount of light hitting the top of the aircraft so that we can adjust how much light we allow to enter the camera sensor.
One thing to note is that most factors that contribute to light issues will reduce transmission of visible light (RGB) more than NIR. With less light, TerrAvion can still process quality NDVI and infrared images, while a natural color image may lose some quality in low light situations. While we always try to fly in optimal flying conditions to capture high-quality imagery for all of our products, long periods of poor weather can prevent our pilots from doing so. In these cases, we are often able to deliver quality NDVI and infrared images even if natural color imagery is sub-optimal. When we have to resort to delivering sub-optimal natural color imagery, we recommend that our customers lean on their synthetic color data. Synthetic color data can help users gain insights they would typically acquire from natural color imagery.
Humidity, pollution, and haze
Humidity, pollution, and haze also cause light scattering and reduce the transmission of light. Water vapor molecules in the atmosphere that are not visible from the ground can negatively impact light quality. So too can pollution and haze. One haze-related issue aerial imagery providers often face is smoke. Wildfires on the West Coast result in poor flying conditions in the area of a fire, but can also impact flight conditions many miles away from the source as the smoke disperses. In the Midwest, controlled field burns have the same effect. Even if there are no burns in your immediate area, smoke from far away burns can travel long distances and deteriorate flight conditions above your farm.
Unfortunately, many of these issues that impact image capture conditions are not only invisible from the ground, but they are also hard to detect from the plane. This means that for every quality image TerrAvion customers receive, our team is often capturing and processing other imagery that turns out to be sub-optimal. In most cases, this imagery is withheld and never delivered.
There are many challenges, including weather and atmospheric effects, that make it difficult to capture aerial imagery on a consistent basis. Every year, TerrAvion makes operation improvements to help our team work around sub-optimal flying conditions. We are always developing new strategies to consistently deliver high-quality imagery to our customers at a frequency they’ve become accustomed to. Stay tuned for more information on our operational improvements for the 2020 season in an upcoming blog post.
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