This data release consists of orthophotographs of the Snow River in Alaska acquired on September 1, 2018. The orthophotographs were produced from images obtained using a Hasselblad A6D-100C 100 megapixel digital mapping camera deployed within a pod mounted on the landing gear of a Robinson R44 helicopter. Images were acquired as the helicopter transited a series of flight lines designed to provide complete coverage, with ample overlap, of the study area along the Snow River. Also within the pod was an ATLANS GPS/Inertial Motion Unit (IMU) that recorded the position and orientation of the platform during the flight. This information was used to geo-reference the images by performing aerial triangulation and bundle adjustment within the TerraSolid software suite, which was also used to produce a LiDAR DEM that was incorporated into the orthophoto production process. The resulting orthorectified imagery had a spatial resolution (pixel size) of 0.05 m. The imagery is saved as a GeoTIFF files with an embedded header that contains the spatial referencing information for the image; the projected coordinate system is UTM Zone 6N, NAD83. The main purpose of these orthophotographs was to provide an ancillary dataset that could be used with a related lidar product and data release.
|Title||Geo-referenced orthophotographs of the Snow River, Alaska, acquired September 1, 2018|
|Authors||Paul J Kinzel, Carl J Legleiter|
|Product Type||Data Release|
|Record Source||USGS Digital Object Identifier Catalog|
|USGS Organization||Integrated Modeling & Prediction Division|