Time Series of Aerial Imagery derived Structure from Motion Products for U.S. Fish and Wildlife Service National Wildlife Refuges in Coastal Delaware, New Jersey, Pennsylvania, and Maryland, 2019 - 2022

Aerial imagery acquired using a fixed wing aircraft fitted with Post-Processing Kinematic (PPK) GPS, was processed using Structure-from-Motion (SfM) photogrammetry techniques to produce high-resolution three-dimensional (3D) point clouds, orthomosaic images, and digital elevation models (DEMs). This dataset, produced by the U.S. Geological Survey (USGS) MD-DE-DC Water Science Center, consists of point clouds generated from the survey of four National Wildlife Refuges in New Jersey and Delaware in order to observe annual changes. Structure-from-Motion software, Agisoft Metashape, was used to perform processing on low-altitude digital aerial imagery acquired by a contractor utilizing a fixed wing aircraft. The aircraft has been modified with a camera port fitted with a Sony A7R camera and equipped with a custom Post-Processing Kinematic GPS device. The surveys were conducted using temporary targets (black and white, 4-square checkered pattern, white round targets, and semi-permanent paved/painted surfaces) distributed throughout the flight operations area as Ground Check Points to supplement the calculated elevation and PPK position data.. All horizontal data are referenced to the North American Datum of 1983 (NAD83 (2011)), and elevation is referenced to the North American Vertical Datum of 1988 (NAVD88). List of sites and their expected release dates (these dates and order of release are subject to change without notice): Prime Hook National Wildlife Refuge - October 2022 Bombay Hook National Wildlife Refugee - December 2022 Supawna Meadows National Wildlife Refuge - Febuary 2022 Good Luck Point - April 2022 Edwin B Forsythe National Wildlife Refuge - June 2022 John Heinz National Wildlife Refuge at Tinicum - August 2022