Drones for Annual Monitoring: Best Practices
There’s a lot of momentum around the adoption of Remote Monitoring for satisfying land trust annual monitoring requirements as set out by The Land Trust Alliance.
LTA has rolled out a new grant program specifically for land trusts to experiment with new remote monitoring techniques, and drones fit nicely into a particular niche. It’s a new space for many, and I’ve gotten a number of questions, that I hope to answer here.
The best place to start is with the Remote Monitoring Best Practices laid out by The Nature Conservancy of California.
This document does a great job covering the various remote monitoring image sources, and defines the current role for each technology based on all the advantages and disadvantages of each.
Below, I’ve tried to answer some of the most frequent questions that come up around drones.
What's the difference between a UAV and a drone?
'UAV' stands for Unmanned Aerial Vehicle, and is synonymous with 'drone'.
For simplicity, the term 'drone' is used here.
When to Use Drones?
Using drones for CE or annual monitoring will be most effective when following these guidelines:
Cost effective for monitoring smaller (less than 400 acres), hard to reach properties (e.g. wetlands).
The highest spatial resolution ortho-imagery available. Good for base-line imagery for new CE or fee title acquisition reports (Section 5.2- b).
Consider add-on benefits like aerial imagery and video asset collection for marketing and communication libraries to get added value from a site visit.
Consider your properties and goals carefully before deciding whether to take a satellite, aerial or drone imagery based approach. Each has a different niche depending on the circumstances.
Spatial Resolution
Drone-based ortho-imagery offers ultra-high spatial resolutions between 2.5 to 3.5 cm per pixel.
This resolution allows land trusts to archive baseline imagery of properties for future comparison to other remote monitoring imagery sources (i.e. satellite).
Additionally, with this resolution, new metrics in stewardship become possible (e.g. landscape-scale invasive plant species mapping over time)
Temporal Resolution
Drones can be a good option for capturing transient conditions like leaf-off/no-snow, or high-water.
Weather limitations affect when a drone can safely be flown, but unlike satellite imagery that is obscured by clouds, capturing drone imagery on overcast days is actually best.
Quick mobilization makes drones a good fit for last-minute imagery collection to satisfy annual monitoring requirements.
Access to Ortho-Imagery
We provide a simple web-based viewer for previewing your ortho-imagery. Data files in GeoTIFF format are available for download and compatible with popular mapping software, including ArcGIS Pro, Google Earth Pro and Upstream Lens.