Alaskan Tundra Surface Water Mosaic Detected from Maxar Satellite Imagery (2001-2021)

### Access
All files can be accessed and downloaded from the directory via: [http://arcticdata.io/data/10.18739/A26Q1SK18](http://arcticdata.io/data/10.18739/A26Q1SK18).

### Overview
This data product contains surface water bodies (excluding ocean) detected from the near infrared band of Maxar satellite imagery across the Alaskan tundra region, as defined by the Circumpolar Arctic Vegetation Map (https://www.geobotany.uaf.edu/cavm/). Maxar satellite imagery was acquired between the years 2001-2021 at a spatial resolution of <1 meter (m). The dataset is stored in GeoPackages organized into grid cells—tiles and subtiles—following the Polar Geospatial Center Mosaic indexing scheme. Each 100 kilometer (km) × 100 km tile contains a 5 × 5 grid of 20 km × 20 km subtiles.

Each GeoPackage includes: (i) the original raster water mask named "water\_raster\_mask" and (ii) a vector layer named "water_vector" derived from the mask boundaries. The vector layer also reports water-covered area (m²) for each polygon. Filtering removes very small objects (< 500 m²) and masks the ocean boundary (National Snow and Ice Data Center) to reduce spurious features.

### 访问方式
所有文件均可通过以下目录链接访问并下载：[http://arcticdata.io/data/10.18739/A26Q1SK18](http://arcticdata.io/data/10.18739/A26Q1SK18)。

### 数据集概览
本数据集包含基于Maxar卫星影像近红外波段反演得到的阿拉斯加苔原区域地表水体（不含海洋）数据，该区域范围由《环北极植被地图》（Circumpolar Arctic Vegetation Map，https://www.geobotany.uaf.edu/cavm/）界定。所用Maxar卫星影像采集于2001至2021年，空间分辨率优于1米（m）。数据集采用GeoPackage格式存储，按照极地地理空间中心（Polar Geospatial Center）镶嵌索引方案组织为网格单元——即图幅与子图幅：每100千米（km）×100千米的图幅包含5×5个20千米×20千米的子图幅。

每个GeoPackage文件包含：(i) 命名为"water_raster_mask"的原始栅格水体掩膜，以及(ii) 由掩膜边界提取得到的矢量图层"water_vector"。该矢量图层同时记录了每个多边形的水体覆盖面积（单位：平方米，m²）。数据经过滤波处理，移除了面积小于500平方米的极小对象，并采用美国国家冰雪数据中心（National Snow and Ice Data Center）提供的海洋边界掩膜以剔除虚假特征。