Maui 2019 elevation (terrain)

Digital Terrain Model (bare earth) 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, bare earth DEM/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_DTM.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）部分区域的裸地形数字地形模型（Digital Terrain Model, DTM）。本数据集所使用的茂宜岛与莫洛凯岛部分区域激光雷达（Light Detection and Ranging, LIDAR）数据由维克斯尔公司（Vexcel, Inc.）采集，茂宜县政府出资采购该数据，以辅助开展高开发度区域的建筑三维建模工作。本数据集为激光雷达衍生的裸地形数字高程模型（Digital Elevation Model, DEM）/高程栅格数据，空间分辨率为1英尺/像素，覆盖茂宜岛与莫洛凯岛部分区域，具体包括莫洛凯岛中部、卡胡卢伊（Kahului）、基黑（Kihei）、拉海纳（Lahaina）以及普库拉尼（Pukalani）。数据的XY坐标单位为英尺，Z高程单位为米。 使用限制： 1. 免责声明——本数据集已置于公共领域，除转售外可自由使用。维克斯尔公司、茂宜县政府以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，用户需通过持证测量师对XYZ坐标值进行验证。本数据仅可作为参考指南，不得作为真实世界地形状况的事实性依据。 2. 垂直基准面——本激光雷达数据集的采集方为科罗拉多州博尔德市的维克斯尔公司（Vexcel Inc.），其将Z高程值基于1988年北美垂直基准面（North American Vertical Datum of 1988, NAVD88）进行解算。但夏威夷州并不承认NAVD88为合法的垂直参考基准。目前夏威夷州尚无官方（法定或实际）的垂直基准面，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）建议将高程值关联至最近的NOAA潮位站。2013年由美国陆军工程兵团（United States Army Corps of Engineers, USACE）生成的老旧激光雷达数据集，则采用NAD83(PA11)作为其垂直参考基准。从理论上讲，由于PA11是以太平洋板块为中心的基准面，该方案可获得更高的Z轴高程精度。在对比无建筑与植被的平坦区域后发现，维克斯尔公司采集的数据的高程值较美国陆军工程兵团2013年的数据集高出约4英尺。针对垂直基准面的问题，维克斯尔公司已收到相关通知，并采用2013年美国陆军工程兵团的激光雷达数据作为垂直控制基准对其采集的数据进行了校正。本次共享的校正后.las格式数据为交付时的原始校正结果。如前所述，使用本数据集的所有风险与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_DTM.html，或联系茂宜县政府（邮箱：[e-mail]）或夏威夷州全域地理信息系统项目（邮箱：[e-mail]）。