2020 Contours, Town of Johnstown

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。本次激光雷达数据的标称点间距（NPS）为0.7米，单航带标称点密度（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）国家地理空间项目激光雷达基础规范2.1版制定。数据采用的水平投影基准为NAD83(2011)/威斯康星州坐标参考系统罗克（美国英尺）（EPSG代码：7629），垂直基准为NAVD88-大地水准面12B（英尺）。激光雷达数据采集使用序列号为4040的Riegl VQ 1560i型传感器，采集时段为2020年4月16日至2020年4月26日，共完成5个航飞架次。数据采集期间，落叶乔木处于无叶状态，地面无积雪，河流水位处于正常或低于正常水平。