Data Management Plan (Deprecated)

This data set consists of a set of aerial triangulated 4-band orthophotos (.tif format) with a .5 meter resolution of the Long Island South Shore that includes the areas of Great South Bay, Moriches Bay, and Shinnecock Bay. The imagery was flown over three days, May 9, 11 and 24, 2018. The digital imagery was acquired by Richard Crouse & Associates(RCA) using an Intergraph DMC2e 230-23522 digital mapping camera. The resulting photographic images were aerotriangulated by Leading Edge Geomatics and reviewed for quality by Dewberry. The imagery was collected under environmental conditions favorable to mapping shallow submerged habitats, in particular seagrass. Missions were timed to coincide with low tide, sun angles below 30 degrees, calm sea state, and low-turbidity. The missions were also scheduled to take advantage of adequate seagrass biomass and minimal brown tide events. Close coordination with local observers on the ground was maintained to ensure good water clarity during data acquisition.

Process Steps:

• 2018-05-01 00:00:00 - Upon receiving the Go-No Go approval from project team to collect imagery, Richard Crouse and Associates collected aerial multi-spectral imagery over the South Shore Estuary Reserve study area at 8, 084 feet above ground level, resulting in a 15cm pixel. The image frames were collected with 60% overlap and 30% sidelap to produce stereo imagery for photogrammetric processing and to help minimize glint issues caused by camera angle. A total of 1208 frames were collected along 18 flight lines generally oriented WSW to ENE.
• 2018-07-23 00:00:00 - Dewberry used previously surveyed Ground Control Points (GCPs) for the mapping effort. 20 checkpoints were used to test the horizontal positional accuracy of the orthophotography. The horizontal positional accuracy specification at the 95% confidence level is 0.734 m. The tested horizontal positional accuracy at the 95% confidence level for the orthophotography passed at 0.241 m. The points are well-defined features, such as sharp corners, path crossings, fence posts, parking lot striping and intersections of driveways with roads. A total of 20 control points were utilized throughout the project area and documented on Photo Control Point Sheets. Each sheet has a written description of the point location, point number, and the coordinates in UTM 18 (northing and easting).
• 2018-07-23 00:00:00 - An aerotriangulation solution was computed by Leading Edge Geomatics using Inpho software issued by Trimble, Inc., utilizing camera calibration reports, digital imagery, and surveyed ground control points. The adjusted control points, camera orientation parameters and pre-existing USGS Digital Elevation Models (DEMs) were then used for digital orthophotography generation in Inpho. The individual georectified orthophotos were then used to create area wide mosaic images in NRGB color band combinations, which were reviewed for quality by Dewberry. A final step was to clip the area-wide mosaic into individual tiles corresponding to U.S. Geological Survey 7.5 minute quarter quad boundaries and name each tile using it's quad name. A slight overlap for each tile ensured comprehensive coverage.