Pan-Arctic 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/A2S17SV7D](http://arcticdata.io/data/10.18739/A2S17SV7D).

### Overview
This data product contains surface water bodies (excluding ocean) detected from the near infrared band of Maxar satellite imagery across the Pan-Arctic 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 less than 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 km (kilometer) × 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 [meters squared]) for each polygon. Filtering removes very small objects (less than 2 m²) and masks the ocean boundary (National Snow and Ice Data Center) to reduce spurious features.

### 数据获取
所有文件均可通过该目录访问并下载：[http://arcticdata.io/data/10.18739/A2S17SV7D](http://arcticdata.io/data/10.18739/A2S17SV7D)。

### 数据集概述
本数据集包含从泛北极苔原区域（依据环北极植被图（Circumpolar Arctic Vegetation Map）划定）的Maxar卫星影像近红外波段中检测得到的地表水体（不含海洋）。所用Maxar卫星影像采集于2001年至2021年间，空间分辨率低于1米（m）。

本数据集以地理数据包（GeoPackages）形式存储，按照极地地理空间中心镶嵌索引方案组织为网格单元——分块与子分块。每块100千米×100千米的分块包含5×5的20千米×20千米子分块网格。

每个地理数据包包含两类内容：(i) 名为`water_raster_mask`的原始栅格水体掩膜；(ii) 由掩膜边界提取得到的名为`water_vector`的矢量图层。该矢量图层同时记录了每个多边形的水体覆盖面积（平方米，m²）。

通过过滤移除了面积小于2平方米的极小对象，并依据国家冰雪数据中心（National Snow and Ice Data Center）的海洋边界掩膜去除虚假特征。