Small Format Digital Aerial Photography

Geo-coded, color-infrared (CIR) digital photography is providing the Florida Gap Project with a practical approach to collecting thousands of ground samples to assist classification of the state's land covers. Over large areas ground surveys are time-consuming and expensive. Inaccessibility of many of the sites because of their remoteness adds to the problem. These surveys remain essential for any classification efforts, but attempts to depend on ground surveys alone for a classification effort that extends across the entire state would be impractical.

Development of the aerial camera setup and collection of imagery is being conducted in cooperation with Drs. Ed Walsh and John Abbitt, Department of Aerospace Engineering, University of Florida While your waiting for these images to load is a good time to scroll down and read more about the camera setup.

Double click on images to load higher resolution versions (~ 300 kb)

Images Approximate Ground Footprint = 250 x 170 meters : 20mm Lens : 1200' Flying Height

Golf Course

Mixed Hardwoods

Depression Marsh

Plantation Pine with Cypress/Swamp Blackgum depression

"Petri Dish" Marsh complex - green splotches are Sawgrass

Images Appoximate Ground Footprint = 40 x 30 meters : 135mm Lens : 1200' Flying Height

Live Oak, Saw Palmetto, Cabbage Palm beside Hypericum Marsh

Hardwoods with Cabbage Palm

as yet unidentified Graminoid

a young Orange Grove

as yet unidentified Graminoid

Coastal Salt Marsh

Coastal Swale and Dune

University of Florida Parking - included here as a scale reference

Shrub in old pasture

as yet unidentified Graminoid

Slash Pine

Before developing the digital camera application, ground surveys were supplemented in South Florida by flying with two 8mm video cameras and a gps unit recording continuous east-west transects following the methods of Slaymaker (xxxx). These aerial transects, one with a 30m footprint and the other with a 400m footprint, proved invaluable in providing a dense set of ground samples which were summarized against the classification.

As the classification moved to North Florida a Kodak DSC 420 color-infrared digital camera was substituted for one of the video cameras. Samples of the CIR digital imagery are shown above. The digital camera has a number of advantages over the video system including,

Two cameras are mounted on a Cessna 172 aircraft. One camera is a Kodak 24-bit digital color infrared digital camera with a 1012 x 1524 fixed plane array. Imagery from the digital camera downloads to a computer on board the aircraft. The other camera is a video camera that is linked to a video recorder inside the plane. An Accuphoto aerial photography control system takes input from an on-board Garmin GPS and a Watson digital gyroscope system that reports pitch, roll, and heading of the aircraft. The GPS has real-time correction from an Accupoint FM signal. The control system uses input from the GPS to direct the path of the pilot along the flightline and trigger the digital camera at uniform intervals (approximately every 10 seconds). Each time the camera is triggered, the Accuphoto unit records the time, GPS position, gyro information and frame information to an onboard computer. With a known pitch, roll, and heading and the GPS position of the plane, it is relatively simple to calculate the coordinates of the center of the image on the ground. In addition, a Horita time-code generator stamps each frame of the video image with the time. The geographic coordinates of the center of each frame of the video is then known by relating the time-stamp back to the computer file of times and GPS positions.