Topobathymetric LiDAR Data (2017)

<b>Note: The files can be downloaded from the Attachments section below. Please note that the total size is 180GB, so the download may take some time depending on your system’s capabilities and configuration. You can also visit https://finder.nyc.gov/orthoimagery to download raw LiDAR data for specific tiles.</b> Topographic and bathymetric LiDAR data was collected for New York City in 2017. Topographic data was collected for the entire city, plus an additional 100 meter buffer, using a Leica ALS80 sensor equipped to capture at least 8 pulse/m². Dates of capture for topographic data were between 05/03/2017 and 05/17/2017 during 50% leaf-off conditions. Bathymetric data was collected in select areas of the city (where bathymetric data capture was expected) using a Riegl VQ-880-G sensor equipped to capture approximately 15 pulses/m² (1.5 Secchi depths). Dates of capture for bathymetric were between 07/04/2017 - 07/26/2017. LiDAR data was tidally-coordinated and captured between mean lower low water (+30% of mean tide) ranges. The horizontal datum for all datasets is NAD83, the vertical datum is NAVD88, Geoid 12B, and the data is projected in New York State Plane - Long Island. Units are in US Survey Feet. To learn more about these datasets, visit the interactive “Understanding the 2017 New York City LiDAR Capture” Story Map -- https://maps.nyc.gov/lidar/2017/ Please see the following link for additional documentation on this dataset -- https://github.com/CityOfNewYork/nyc-geo-metadata/blob/master/Metadata/Metadata_LiDAR_Summary.md

<b>注意：以下附件可下载本数据集文件。请注意数据集总大小为180GB，下载耗时将取决于您的系统性能与配置。您也可访问https://finder.nyc.gov/orthoimagery，下载特定图幅的原始激光雷达（LiDAR）数据。</b>2017年，纽约市完成了地形与水深激光雷达（LiDAR）数据的采集工作。其中，地形数据覆盖全市范围及额外100米缓冲区，采用徕卡（Leica）ALS80传感器采集，该传感器配置为至少每平方米8个激光脉冲。地形数据采集日期为2017年5月3日至2017年5月17日，此时植被落叶覆盖率约为50%。水深数据采集于城市选定区域（即预期需采集水深数据的区域），采用Riegl VQ-880-G传感器采集，该传感器配置为每平方米约15个激光脉冲（对应1.5倍赛氏盘深度（Secchi depths））。水深数据采集日期为2017年7月4日至2017年7月26日。所有激光雷达数据均经过潮汐校准，采集时段介于平均低潮水位（平均潮汐的+30%）区间内。所有数据集的水平基准为NAD83，垂直基准为NAVD88（配准Geoid 12B大地水准面），数据投影采用纽约州平面坐标系-长岛分带，单位为美国测量英尺（US Survey Feet）。如需了解更多数据集相关信息，请访问交互式故事地图《2017年纽约市激光雷达采集指南》：https://maps.nyc.gov/lidar/2017/。如需查阅本数据集的补充文档，请访问：https://github.com/CityOfNewYork/nyc-geo-metadata/blob/master/Metadata/Metadata_LiDAR_Summary.md