2020 Contours, Town of Union

The Rock County lidar project area covers approximately 771 square miles which includes a 100 meter buffer around the county boundary. The lidar data was acquired at a nominal point spacing (NPS) of 0.7 meters and a single swath nominal point density (NPD) of 2.0. Project specifications are based on Rock County requirements and on the U.S. Geological Survey National Geospatial Program LiDAR Base Specification, Version 2.1. The data was developed based on a horizontal projection/datum of NAD83(2011) / WISCRS Rock (ftUS) (EPSG Code: 7629), and vertical datum of NAVD88 - Geoid12B (Feet). LiDAR data was acquired using a Riegl VQ 1560i sensor with serial number 4040 from April 16, 2020 to April 26, 2020 in 5 total lifts. Acquisition occurred with leaves absent from deciduous trees, when no snow was present on the ground, and with rivers at or below normal levels.罗克县激光雷达（LiDAR）项目作业区总面积约771平方英里，涵盖县界周边100米缓冲区。本次采集的激光雷达数据名义点间距（NPS）为0.7米，单条航带名义点密度（NPD）为2.0。本项目技术规范基于罗克县相关要求及美国地质调查局（U.S. Geological Survey）国家地理空间计划激光雷达基础规范2.1版制定。数据采用的水平投影/基准面为NAD83(2011) / WISCRS Rock (ftUS)（EPSG代码：7629），垂直基准面为NAVD88 - Geoid12B（英尺）。激光雷达数据采集使用序列号为4040的Riegl VQ 1560i传感器，于2020年4月16日至2020年4月26日间分共5次飞行航次完成作业。数据采集时机选择为落叶乔木无叶、地面无积雪且河流水位处于正常或低于正常水平的时段。