t25r05tree point

This layer provides an approximate inventory of tree center points for King County in 2021. Tree points were derived through an automated process using 2021 lidar, Ecopia land cover, and NAIP imagery. This layer provides an estimate of tree location and tree height from lidar, tree type (evergreen vs decidious) from lidar intensity, and vegetation health from imagery using NDVI. The points in this layer have not been QA/QC'd or field verified. This layer is not as accurate as a ground inventory would be. However, there are ~101,000,000 trees in King County, so this analysis provides a feasible approximation of tree location and density at a fraction of the cost and effort. Because there are so many features, the layer has been split into tiles of about 1 - 2 million points. Use the Tree Point Index polygon layer to identify which tiles you need to cover your area of interest. All tree point features are turned on by default, but restricted to a max of 1:10,000 scale for visibility. If you don't see tree points when you load this layer, zoom in further and wait a few seconds for the layer to render. To improve performance, turn off tree point tile layers you don't need. For detailed information on how this layer was derived, please see the History of Building- Vegetation Height, & Tree Canopy at King County storymap. For lidar intensity values, 0-120 = Deciduous, 120-200 = Conifer, 200-255 = Other. This is an estimated range. NDVI values range from -1 to 1, with values closer to 1 indicating lush green vegetation. Tree height is measured in feet above the bare earth DEM. A “tree” in this layer is any vegetation taller than 10 feet. No updates are planned for this layer.

本图层提供了2021年金县（King County）树木中心点的近似清查数据集。树木点位通过自动化流程生成，所用数据源涵盖2021年激光雷达（lidar）数据、Ecopia土地覆盖数据以及NAIP影像。本图层可基于激光雷达数据估算树木位置与树高，通过激光雷达强度值识别树木类型（常绿与落叶树种），并借助归一化差分植被指数（NDVI）反演植被健康状况。本图层中的点位尚未经过质量控制与质量保证（QA/QC）流程及野外实地验证，其精度不及地面实地清查结果。不过，金县境内约有1.01亿棵树木，因此本分析以极低的成本与人力投入，实现了区域内树木位置与密度的可行近似估算。由于要素总量庞大，本图层已被切分为单幅包含约100万至200万点位的瓦片。可通过树木点位索引面图层（Tree Point Index），确定覆盖研究区域所需的瓦片范围。所有树木点位要素默认处于启用状态，但可见性被限制在1:10000比例尺范围内。若加载图层后未显示树木点位，请进一步放大视图并等待数秒直至图层渲染完成。为提升加载性能，请关闭无需使用的树木点位瓦片图层。关于本图层生成方式的详细信息，请参阅金县《建筑-植被高度与树冠覆盖构建历程》专题故事地图（storymap）。激光雷达强度值的估算分类规则为：0~120对应落叶树种，120~200对应针叶树种，200~255对应其他植被类型，该分类范围仅为估算值。归一化差分植被指数（NDVI）的取值范围为-1至1，数值越接近1，代表植被越繁茂翠绿。树高以裸地面数字高程模型（DEM）为基准，单位为英尺。本图层中定义的“树木”指所有高度超过10英尺的植被。本图层暂无后续更新计划。