Originally published in North America Clean Energy Magazine
Challenges of Aerial Surveys
Aerial surveys can be expensive, time-consuming, potentially impactful to wildlife, and are technologically difficult when attempting to effectively navigate and document findings. Yet, aerial surveys are often conducted before and after construction projects, particularly for renewable energy projects, either to comply with regulations or to minimize asset loss. Fortunately, evolving technology is creating new opportunities to address these needs that increase aerial survey efficiency; saving developers, investors, and agencies time and money.
Traditional Data Collection Methodology
To successfully complete an aerial survey, biologists have three general requirements, including the ability to 1) view their location inside the survey boundaries; 2) record GPS points; and 3) record their flight path to track their progress and achieve agency reporting requirements.
To meet these requirements, biologists often utilize traditional methodology, which generally includes using a handheld GPS unit with a preloaded map showing survey boundaries as well as an electronic data form to document the location and information on nests, vegetation, etc., in the GPS. In addition, biologists use paper datasheets and even printed maps (aerials or quads) as a backup for navigation and documentation.
Use of a handheld GPS unit provides some benefits, including the ability to record data points with some location accuracy as well as the ability to electronically capture GPS coordinates and transition these points to a GIS database without manually transcribing them. However, there are several pitfalls associated with this technology as well.
Primarily, these handheld devices are not specifically designed to track the user and record GPS data while flying; therefore, they rarely communicate with satellites fast enough to adequately track the helicopters flight path. Furthermore, since the single handheld device is trying to be both a computer and a GPS solution, the computer’s processing power suffers greatly. This commonly results in technical glitches with the device during the survey that can result in additional flight hours. In addition, it is difficult for the biologists to track their location on the small screen of the GPS device, particularly when the survey area is extensive. Also, utilizing a satellite image of a large project area can bog down the memory of the handheld GPS unit and cause the unit to crash.
The Benefits of New Mobile Technology
Recent technological advancements in the form of tablets with mobile GIS software paired through Bluetooth with external GPS receivers are providing new opportunities to aerial surveyors that can substantially increase efficiency and accuracy while simultaneously reducing potential impacts to wildlife. GPS receivers that we have used include the Arrow 100 for submeter accuracy and the Bad Elf GPS Pro with 2.5-meter accuracy. The appropriate GPS receiver depends on your projects accuracy requirements.
When paired with the GPS receiver, the tablet increases survey efficiency, thus reducing the total flight hours. Since renting a helicopter and a pilot can cost upwards of $1,600 per hour in our experience, before the cost of the two on-board biologists, any efficiency gains can greatly reduce the overall cost of the survey project. These efficiencies are achieved through several benefits during the survey, including the use of an external GPS receiver that communicates up to ten times faster with satellites, reducing glitches during the survey; eliminating the need for cellular service to find your current location, and more accurate tracking of the flight path. In addition, it saves on post survey data documentation by eliminating the need to transpose data from paper data sheets to electronic format.
This increase in efficiency and ease of use are made possible by the ability for the surveyor to more easily record data points electronically; ability to view the entire survey area over satellite imagery and quickly zoom in and out to specific locations with a touchscreen; and the ability to upload all of the data quickly at the end of the day without transcribing additional data from paper maps. Some GPS receivers (e.g. the Bad Elf GPS Pro+©) will also allow you to automatically export a KMZ file showing the flight path in Google Earth.
Software is the Key
Every mobile GIS software app has its pros and cons, and we have tested most of the apps on the market. The app that we always return to is iGeotrak by Cogent 3D. This app has the benefit of being around for longer than most and has the best satellite imagery viewing ability out there. Different than other apps where you have to download a lower quality map for use offline or disconnected from cellular service, iGeotrak allows the user to cache the native Apple satellite imagery for as large an area and at all the zoom levels desired. iGeotrak will then remember that cache once you begin your work disconnected. This has allowed us to fly projects as large as 100 square miles disconnected and be able to see all our surroundings from trees to cliffs, transmission lines to radio towers, and more easily record raptor nest locations. iGeotrak also has the ability to have detailed data collection forms that can then be exported as a Word document or PDF at the push of a button.
For Project’s where we have utilized the tablet solution, we have cut aerial survey hours by 20-30 percent based on a comparison of flight hours using traditional technology. These cost savings were a direct result of easier navigation, quick GPS coordinate recording, better mapping of the flight path, and the external GPS receiver’s ability to maintain position information without glitches. We have used this solution extensively for both field and aerial surveys, including routing surveys, threatened and endangered species surveys, aerial raptor nest surveys, eagle point count surveys, noxious weed monitoring, habitat mapping, and wetland delineations. The potential for this technology will only continue to expand, providing additional opportunities for developers and agencies to save time and money in the future.