Flying Over Manor Farm, Chearsley: A Drone Survey Journey

Our GIS team has developed an interactive StoryMap to showcase the findings from a drone survey conducted at Manor Farm in Chearsley. In this post, Benedetta De Luigi, one of our GIS technicians, shares the process and technology behind the survey, the insights obtained from the high-resolution imagery, and the benefits of using drone technology for biodiversity net gain planning, and habitat management and monitoring.

Creating detailed habitat management and monitoring, and biodiversity net gain concept plans requires an accurate and up-to-date understanding of a site’s habitat and biodiversity. Readily available aerial imagery (e.g., Google Earth satellite imagery) often falls short in depicting real-time conditions.

Last year, this was the case at Manor Farm in Chearsley, Buckinghamshire, an enclosed farmland comprised of arable fields and grassland utilised for grazing cows and sheep. After analysing existing imagery, we discovered that newly created ponds were missing. To account for these elements in the plans, we needed a closer look at these new features.

That’s when our team of qualified eBee X drone pilots took to the skies to facilitate the creation of comprehensive plans for the site.

Creating a flight plan

To prepare for the drone flight, we created mission blocks within the site boundary using eMotion flight planning software. Mission blocks allow us to create flight lines to achieve the desired spatial resolution (in this case an incredibly high resolution of 2.6cm per pixel), ensuring that we meet regulations and avoid unsafe areas like high-traffic roads and railways.

After receiving permissions from the landowner, we carried out an on-site survey to assess safe fly conditions and identify any necessary precautions. Our drone team is all GV (General Visual Line of Sight) certified, meaning they can act as either the pilot or spotters on the ground during flights to maintain line of sight of the drone and monitor the airspace for hazards.

Capturing the details

As the eBee X drone follows the mission blocks planned in eMotion, it takes an image in the visible range at each waypoint. These separate images are then stitched together in post-processing to create a cohesive, detailed imagery tile that covers the entire survey area.

The final result

Comparing the drone imagery with the original aerial imagery, the enhanced detail and presence of the new ponds were evident, providing a more accurate view of the site’s habitats and biodiversity. We were also able to establish a more detailed overview of other habitats, such as ditches, scrub, and woodland canopies, providing a more up-to-date and accurate representation of each habitat type for mapping than would otherwise have been provided by available aerial images. The data allowed us to create a 3D digital surface model of the site, offering insights into the relationship between the site’s topography and habitat distribution, which further informed design options for future biodiversity gain.

The level of mapping clarity and accuracy provided by the drone is invaluable for biodiversity net gain planning, where habitat values, together with measures of biodiversity losses and gains, are dependent on precise habitat area measurements. Miscalculation of habitat data, either through in-field estimates or poor quality/out of date aerial images, has the potential to significantly undervalue or overvalue biodiversity change. This leads to potential losses and deterioration of biodiversity and can have significant financial implications for developers and landowners seeking to minimise losses or maximise gains in biodiversity through the mandatory net gain market.

Explore our interactive StoryMap to see the detailed imagery and insights from our drone survey at Manor Farm.