Yarmouth Wetlands (NWI)

Overview This feature service provides detailed geospatial information on wetlands and deepwater habitats located within the state of Massachusetts. The data is derived from the National Wetlands Inventory (NWI) Version 2 and integrates multiple sources to delineate the areal extent of wetlands and surface waters in this region. Feature Layers National Wetlands Inventory: This primary layer represents the extent, approximate location, and type of wetlands and deepwater habitats. The wetland data follow definitions from Cowardin et al. (1979) and include supplemented hydrography data from the U.S. Geological Survey’s National Hydrography Dataset (NHD) to capture linear features such as streams and other surface waters. Certain habitats like seagrasses, submerged aquatic vegetation, and deepwater reef communities are excluded due to limitations in aerial imagery detection. Farmed wetlands may also be partially excluded based on regulatory definitions. Geographic Coverage The dataset covers the Town of Yarmouth, MA and a 5 mile radius around the extent of the town's boundary. Data Sources and Quality The data was downloaded from the official MassGIS portal and represents the most recent update as on Spring 2026. It is projected for use within Massachusetts.

数据集概述
本要素服务提供马萨诸塞州境内湿地与深水生境的详细地理空间信息。数据源自国家湿地名录（National Wetlands Inventory, NWI）V2，并整合多源数据以精准勾绘该区域湿地与地表水的面积分布范围。

要素图层
国家湿地名录图层：该主图层展示了湿地与深水生境的分布范围、大致位置及类型。湿地数据遵循考瓦尔丁（Cowardin）等人1979年提出的定义，并补充了美国地质调查局（U.S. Geological Survey）国家水文数据集（National Hydrography Dataset, NHD）的水文数据，以捕获溪流及其他地表水等线性地物。受航空影像解译能力限制，海草床、沉水水生植被及深水礁群落等生境未被纳入；根据监管定义，人工养殖湿地也可能存在部分数据缺失。

地理覆盖范围
本数据集覆盖马萨诸塞州雅茅斯镇，以及该镇行政边界向外5英里半径范围内的区域。

数据来源与质量
本数据从马萨诸塞州官方地理信息系统（MassGIS）门户下载，为2026年春季的最新更新版本，坐标系适配马萨诸塞州本地使用。