Maine Orthoimagery Coastal South Coast 2021

This dataset consists of true color aerial imagery of the Pisctaqua coastal region between York, ME and Cape Elizabeth, ME and was captured at 14.5-cm GSD and used to produce high resolution 6” orthorectified imagery with a one-foot accuracy. Imagery was collected on June 28th and 29th, 2021, during low tide conditions and within two hours of spring tides. Additional atmospheric considerations that were considered before each lift included flying in a sun angle between 25 degrees and 50 degrees, no more than 10% cloud cover, and less than 10 knots of a maximum predicted wind velocity. Additionally, flights were only be dispatched after a precipitation-free period of at least 48 hours. The project area consisted of approximately 400 images on approximately 7 flight lines with 60% forelap and 30% sidelap. Airborne GPS and IMU were be utilized during the acquisition to improve the aerotriangulation solution. Raw imagery was acquired using the Vexcel Eagle 80-mm Mark 3 mounted on a fixed wing aircraft and flown at an elevation of approximately 9,500 feet. Digital ortho-rectified imagery was created using the raw digital aerial imagery, ground control, aerotriangulation, and a digital elevation model. Existing State of Maine ground control was utilized in the aerotriangulation solution for this project. These aerial survey products were under contract for the State of Maine Department of Environmental Protection. Bluesky Geospatial captured the raw aerial imagery and James W. Sewall processed the raw imagery to develop the aerotriangulation solution and to create digital orthophotos and related products. Normandeau Associates served as Aerial Survey Coordinator to verify that project specifications were met.本数据集包含美国缅因州约克（York, ME）至伊丽莎白角（Cape Elizabeth, ME）之间的皮斯卡塔夸（Pisctaqua）沿海区域的真彩色航空影像，采集时的地面采样距离（Ground Sample Distance, GSD）为14.5厘米，用于生成精度达1英尺的高分辨率6英寸正射影像。 影像采集于2021年6月28日至29日，采集时段为低潮期且处于春汛前后两小时范围内。 每次飞行作业前需满足多项环境与气象要求：太阳高度角介于25°至50°之间、云量不超过10%、最大预测风速低于10节；且仅在至少48小时无降水的时段后方可安排飞行任务。 本次项目作业区域共规划约7条飞行航线，采集影像约400张，航向重叠率为60%，旁向重叠率为30%。 采集过程中集成机载GPS与惯性测量单元（Inertial Measurement Unit, IMU），以优化空中三角测量解算结果。原始影像由搭载于固定翼飞机上的Vexcel Eagle 80毫米Mark 3型相机采集，飞行高度约为9500英尺。 数字正射影像基于原始航空影像、地面控制点、空中三角测量解算结果及数字高程模型（Digital Elevation Model, DEM）生成。本项目的空中三角测量解算采用缅因州现有地面控制点数据。 本航空测绘产品为缅因州环境保护局（State of Maine Department of Environmental Protection）委托开发项目成果。原始航空影像由Bluesky Geospatial采集；原始影像的空中三角测量解算、数字正射影像及相关产品的加工处理由James W. Sewall完成；Normandeau Associates担任本次航空测绘协调方，负责核验项目技术规范的符合性。