Data Management Plan

The 2012 American Samoa aerial photography project produced 1' (.30m) GSD multispectral digital orthoimagery for approximately 85 square miles of the American Samoa islands of Tutuila, Aunu'u, Ofu, Olosega, and Ta'u. An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed, thus it combines the image characteristics of a photograph with the geometric qualities of a map.

Original contact information:

Contact Name: Mike Duncan

Contact Org: United States Geological Survey

Phone: 573-308-3579

Email: e-mail: jduncan@usgs.gov

Process Steps:

• 2012-01-01 00:00:00 - Sixty-five (65) photo identifiable control locations were selected and surveyed to adequately cover the entire state. Details of each point can be found in the full control report. Accuracies of 10cm or better (horizontally and vertically) were required. | Source Produced: Georeferenced Aerial Imagery
• 2012-01-01 00:00:00 - New digital aerial imagery was obtained in the spring of 2012 using a large format Microsoft Vexcel Ultracam equipped with Airborne GPS/IMU. A total of 22 flight lines with 671 frames were collected in multispectral (RGB and NIR) 12 bits per band format. The imagery was acquired with a 100.5 mm focal length at an altitude of 9,000' above mean terrain, to yield a raw pixel resolution of 1' (.30 m) suitable for photogrammetric mapping and orthophoto production. The 'leaf condition' was not a concern but imagery was collected in the summer of 2012 under conditions free from flooding and excessive soil moisture. Within populated areas, no more than 5% clouds, cloud shadows, smoke, and haze are permitted. In the uninhabited areas of the islands 10% of clouds, cloud shadows, smoke, and haze may exist. There is no tide coordination. The sun angle threshold was 30 degrees. To ensure complete coverage, photography was collected for all tiles that intersected the islands of American Samoa (Tutuila, Aunnu'u, Ofu, Olosega, and Ta'u). Orthoimages were visually inspected for completeness to ensure that no gaps or image misplacements exist within and between adjacent images. | Source Produced: Raw Aerial Imagery
• 2012-01-01 00:00:00 - Imagery and AGPS/IMU data is downloaded from the hard drive on the plane to the hard drive on the ground. AGPS/IMU mission data is processed together with continuously collected ground-based CORS GPS base station data in forward and reverse directions. This precisely determines the aerial camera's position and orientation in the terrain (project) coordinate system and allows for correct orientation of the imagery. | Source Produced: Exterior Orientation File
• 2012-01-01 00:00:00 - The EOFILE, raw frames, and control points were input into ISAT in order to complete the SoftCopy Aerotriangulation, described in ATSOL source contribution, and assembled into a block. A second degree block adjustment is run along with the full least squares bundle adjustment. Once the last set of blunders and adjustments are complete, a final block bundle adjustment is run to produce the final solution. The final adjustment of the block is accomplished by using a rigorous simultaneous least squares bundle adjustment. The general procedure is to remove all blunders from the data using automatic blunder detection. The bundle adjustment is then run with minimal ground control to test the photogrammetric measurements for consistency. Next, the full ground control data set, including ABGPS data, is added to the adjustment. The horizontal control is then tightened and the effect on the vertical control and the photogrammetric residuals are inspected. The final adjustment makes sure that all of the measurements are in balance with each other and properly represent the actual conditions. | Source Produced: Stereo Imagery (Citation: Raw Aerial Imagery)
• 2012-01-01 00:00:00 - The rectification process required as input a digital elevation model (LiDAR_DEM), imagery (IMG1) and soft copy aerotriangulation solution (ATSOL). The orthorectified imagery was produced using Intergraph Orthopro software. It used ImageStation Photogrammetric Manager (ISPM) for photogrammetry project setup, file management, and importing triangulation data from a user defined ASCII file (ATSOL). The ortho project records all the operations, including all the parameters that are defined through the OrthoPro workflow, such as the project area coordinates, pixel size, rotation angle, ISPM project and its unorthorectified source images, product areas (TLDEF) orthorectification settings, seamlines and so on. The results are single frame images that have yet to be mosaicked into manageable tiled orthos. The single frame orthos were checked for accuracy against the surveyed ground control before further image editing.
• 2012-01-01 00:00:00 - Orthorectified imagery was mosaicked, locally color-balanced and cut to the tile definition boundaries (TLDEF) using Intergraph Orthopro software. Tiled orthophotos then went through a rigorous manual QC process to evaluate for remaining hotspots (sun reflectance over water), tone quality, color balance and the feathering area along seamlines. Any imperfections at this point were manually edited. Clouds and cloud shadows were attempted to be minimized by using alternate views from adjoining frames. The tiled images were then converted to the required file format (GeoTIFF) and transferred to external hard drives for delivery to USGS. | Source Produced: Tiled Orthophoto

https://coast.noaa.gov/dataviewer. This data set is dynamically generated based on user-specified parameters.;