| Description |
This portion of the data release presents the raw aerial imagery collected during an Unmanned Aerial System (UAS) survey of the intertidal zone at Post Point, Bellingham Bay, WA, on 2019-06-06. The imagery was acquired using a Department of Interior-owned 3DR Solo quadcopter fitted with a Ricoh GR II digital camera featuring a global shutter. The camera was mounted using a fixed mount on the bottom of the UAS and oriented in an approximately nadir orientation. The UAS was flown on pre-programmed autonomous flight lines which were oriented roughly shore-parallel and were spaced to provide approximately 70 percent overlap between images from adjacent lines. Three flights (F01, F02, F03) covering the survey area were conducted at an approximate altitude of 70 meters above ground level (AGL), resulting in a nominal ground-sample-distance (GSD) of 1.8 centimeters per pixel. Two additional flights (F04, which was aborted early and not included in this data release, and F05) were conducted over a smaller area within the main survey area at an approximate altitude of 35 meters AGL, resulting in a nominal GSD of 0.9 centimeters per pixel. The camera was triggered at 1 Hz using a built-in intervalometer. After acquisition, the images were renamed to include the flight number and acquisition time in the file name. The coordinates of the approximate image acquisition locations were added ('geotagged') to the image metadata (EXIF) using the telemetry log from the UAS onboard single-frequency autonomous GPS. The image EXIF were also updated to include additional information related to the acquisition. Although the images were recorded in both JPG and camera raw (Adobe DNG) formats, only the JPG images are provided in this data release. The data release includes a total of 1,662 JPG images. Images from takeoff and landing sequences were not used for processing and have been omitted from the data release. The images from each flight are provided in a zip file named with the flight number. [More]
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