ImageryOrthoimagery_Helene_2025

Product: These data were acquired by the NC Collaboratory at UNC Chapel Hill utilizing funds appropriated by the NC General Assembly. This orthoimagery data set includes 6 in digital orthoimages in GeoTIFF tiles and 32-bit 4-band (RGBIR).Geographic Extent: 13 counties in NorthCarolina, covering approximately 5,323 total square miles. Counties covered in their entirety for this project included: Alexander, Ashe, Watauga, Avery, Mitchell, Burke, Yancey, McDowell, Rutherford, Buncombe, Henderson, Haywood, and Jackson. Dataset Description: The Helene-North Carolina Priority 1 Lidar and Imagery project called for the planning, acquisition, and processing of imagery data to be collected at a ground sample distance (GSD) of 6 in. Project specifications are based on the American Society of Photogrammetry and Remote Sensing (ASPRS) standards. The data were developed based on a horizontal projection/datum of NAD 1983 2011 StatePlane North Carolina FIPS 3200 US Survey Foot. Imagery data were delivered as 6 in GeoTIFF tiles and 32-bit 4-band (RGBIR). Tiled deliverables contained 6,768 individual 5,000 ft x 5,000 ft tiles.Ground Conditions: Imagery was collected in spring 2025, and meets project acquisition parameters of being snow and ice free (though some light, undrifted snow may be present), no unusual flooding or water inundation, and leaf off conditions. The AECOM team established a total of 49 check points to assess the horizontal accuracy of the data, of which 39 were useable. The imagery data was post processed to meet task order specifications and was tested to meet ASPRS horizontal accuracy guidelines. Seamline editing and photoshop adjustments were focused on major transportation features due to the rapid response nature of the project and the need for damage analysis. Areas outside of major transportation features may exhibit seamline displacement and other anomalies such as smears.产品说明：本数据集由北卡罗来纳大学教堂山分校（UNC Chapel Hill）下属的北卡罗来纳协作实验室（NC Collaboratory）使用北卡罗来纳州议会（NC General Assembly）拨付的经费采集完成。该数字正射影像（orthoimagery）数据集包含6英寸分辨率的GeoTIFF格式瓦片影像，以及32位4波段（RGBIR）影像数据。 地理覆盖范围：覆盖北卡罗来纳州13个县，总面积约5323平方英里。本项目完整覆盖的县包括：亚历山大县（Alexander）、阿什县（Ashe）、沃托加县（Watauga）、埃弗里县（Avery）、米切尔县（Mitchell）、伯克县（Burke）、扬西县（Yancey）、麦克道威尔县（McDowell）、拉瑟福德县（Rutherford）、邦科姆县（Buncombe）、亨德森县（Henderson）、海伍德县（Haywood）以及杰克逊县（Jackson）。 数据集说明：海伦-北卡罗来纳州优先级1激光雷达（Lidar）与影像项目要求开展影像数据的规划、采集与处理工作，采集的地面采样距离（Ground Sample Distance，简称GSD）为6英寸。本项目技术规范符合美国摄影测量与遥感学会（American Society of Photogrammetry and Remote Sensing，简称ASPRS）标准。数据采用NAD 1983 2011州平面坐标系北卡罗来纳分带（FIPS 3200 美国测量英尺）作为水平投影基准。影像数据以6英寸分辨率的GeoTIFF格式瓦片及32位4波段（RGBIR）形式交付，共包含6768张单张尺寸为5000英尺×5000英尺的瓦片文件。 地面采集条件：影像采集于2025年春季，符合项目采集参数要求：无积雪与积冰（但可能存在少量未堆积的薄雪）、无异常洪水或水体淹没，且处于落叶状态。AECOM团队共设置49个检查点以评估数据的水平精度，其中39个检查点数据有效。影像数据经过后处理以符合任务订单技术规范，并通过检测满足ASPRS水平精度指南要求。鉴于本项目的快速响应属性及灾害损伤分析需求，接缝线编辑与Photoshop调整主要针对主要交通沿线区域开展。非主要交通沿线区域可能存在接缝线偏移及涂抹等异常问题。