Maui_2019_DSM

Digital Surface Model of parts of Maui and Molokai. Partial coverage Vexcel, Inc. LIDAR of Maui and Molokai were purchased by County of Maui to assist with three-dimensional modeling of structures in areas of higher development. 1'/px, LIDAR-derived, digital surface elevation raster of parts of Maui and Molokai – specifically, Central Molokai, Kahului, Kihei, Lahaina and Pukalani. XY units: feet, Z units: meters. Use Limitations: 1.Disclaimer - This dataset is being placed in the public domain. Any use is allowed except for re-sale. Neither Vexcel, Inc., the County of Maui, nor the State of Hawaii make any guarantees, expressed or implied, regarding its accuracy or fitness of use. Users should verify XYZ values through a licensed surveyor for any engineering application. This data should only be used as a guide, vs. a statement of fact regarding real-world conditions. 2.Vertical Datum - The originator of this LIDAR dataset, Vexcel Inc. of Boulder, Colorado referenced Z values to the North American Vertical Datum of 1988 (NAVD88). NAVD88 is not recognized as a valid vertical reference for the state of Hawaii. Currently Hawaii has no official (de jure or de facto) vertical datum, and NOAA's National Geodetic Survey (NGS) recommends that elevations be referenced to the nearest NOAA tidal gauge. A legacy LIDAR dataset produced in 2013 by the United States Army Corps of Engineers (USACE) used NAD83(PA11) as its vertical reference. In theory this approach should result in better accuracy for the Z dimension as PA11 is a Pacific plate-centric datum. In comparing flat areas containing neither structures or vegetation, it was found that the Vexcel values sit approximately 4 feet above the USACE dataset. The vertical datum issue was brought to the attention of Vexcel, Inc. Vexcel used the 2013 USACE LIDAR as vertical control to correct their LIDAR data. The (corrected) .las data is shared as it was delivered. As stated above, the use of this data transfers all risks and assumption of responsibility to the user For more information see https://files.hawaii.gov/dbedt/op/gis/data/Maui_2019_DSM.html or contact County of Maui at [e-mail] or Hawaii Statewide GIS Program at [e-mail].茂宜岛（Maui）与莫洛凯岛（Molokai）部分区域数字表面模型（Digital Surface Model, DSM）。茂宜县（County of Maui）采购了Vexcel公司针对茂宜岛与莫洛凯岛的部分覆盖激光雷达（Light Detection and Ranging, LiDAR）数据，用于辅助开展高开发强度区域的建筑三维建模工作。本数据为LiDAR衍生的数字地表高程栅格数据，分辨率为1英尺每像素（1'/px），覆盖范围涵盖茂宜岛与莫洛凯岛的部分区域，具体包括莫洛凯岛中部、卡胡卢伊（Kahului）、基黑（Kihei）、拉海纳（Lahaina）及普卡拉尼（Pukalani）。数据的XY轴单位为英尺，Z轴单位为米。 使用限制： 1. 免责声明：本数据集已纳入公有领域，除转售外可自由使用。Vexcel公司、茂宜县及夏威夷州均不对本数据集的准确性或适用性作出任何明示或默示担保。若将本数据用于工程类应用，用户需通过持牌测量师核实XYZ坐标值。本数据仅可作为参考指南，不得作为实地真实状况的事实性表述。 2. 垂直基准面：本LiDAR数据集的原始创建方——科罗拉多州博尔德市的Vexcel公司，将Z值参考至1988年北美垂直基准面（North American Vertical Datum of 1988, NAVD88）。但NAVD88未被夏威夷州认定为有效的垂直参考基准。目前夏威夷州暂无法定或实际的官方垂直基准，美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）下属的国家大地测量局（National Geodetic Survey, NGS）建议将高程参考至最近的NOAA验潮站。2013年由美国陆军工程兵团（United States Army Corps of Engineers, USACE）制作的历史LiDAR数据集采用NAD83(PA11)作为其垂直参考基准。理论上，由于PA11是以太平洋板块为核心的基准面，其Z轴维度的精度更优。在对比无建筑与植被的平坦区域时，发现Vexcel数据集的数值较USACE数据集高出约4英尺。相关垂直基准面问题已告知Vexcel公司，Vexcel公司以2013年USACE的LiDAR数据作为垂直控制资料对其LiDAR数据进行了校正。校正后的.las格式数据已按交付时的原始状态共享。如前所述，使用本数据集的所有风险及责任均由用户自行承担。 如需获取更多信息，请访问https://files.hawaii.gov/dbedt/op/gis/data/Maui_2019_DSM.html，或联系茂宜县的[e-mail]，或夏威夷州全域GIS项目组的[e-mail]。