Global River Widths from Landsat (GRWL) Database

If you use the GRWL Database in your work, please cite: Allen and Pavelsky (2018) Global Extent of Rivers and Streams. Science. https://doi.org/10.1126/science.aat0636 This long-term repository contains three files: 1) Simplified GRWL Vector Product: GRWL_summaryStats_V01.01.zip 2) GRWL Mask (raster): GRWL_mask_V01.01.zip 3) GRWL Vector Product: GRWL_vector_V01.01.zip Other data: - Location map of the individual GRWL tiles: Shapefile download - River and stream surface area totals by drainage basin (Fig. 4 in Allen & Pavelsky, 2018): Shapefile download 1) Documentation for the Global River Width from Landsat (GRWL) Simplified Vector Product V01.01 This zip file contains a single ESRI shapefile polyline of river centerlines. Projection: Geographic WGS84 This file is a simplified version of the raw GRWL vector product (see #3 below). This product is a smaller and more wieldy compared to the raw GRWL vector dataset and most users of GRWL will prefer to use this simplified version. This simplified vector product reduces the number of feature vertices and attributes by simplifying the polyline geometry and by calculating summary statistics along each polyline segment. Polyline segments are roughly the line segments between each tributary junction. For each polyline segment, the shapefile contains the following attributes: 1. width_min: the minimum of river width measurements along the segment at mean discharge (meters) 2. width_med: the median of river width measurements along the segment at mean discharge (meters) 3. width_mean: the mean of river width measurements along the segment at mean discharge (meters) 4. width_max: the maximum of river width measurements along the segment at mean discharge (meters) 5. width_sd: the standard deviation of river width measurements along the segment at mean discharge (meters) 6. lakeflag: integer specifying if segment is located on a river (lakeflag=0), lake/reservoir (lakeflag=1), tidal river (lakeflag=2), or canal (lakeflag=3). This information is of much higher quality in the Global River Width from Landsat (GRWL) Vector Product V01.01 (product #3 below). 8. nSegPx: number of pixels within the segment (N pixels) 9. Shape_Leng: length of the segment (kilometers) 2) Documentation for the Global River Width from Landsat (GRWL) Mask V01.01 This zip file contains 830 GeoTIFF tiles of water masks at mean discharge. The assembly of this database is described in Allen and Pavelsky (2018) “Global Extent of Rivers and Streams” published in Science. The GRWL mask is an intermediate product in the production the GRWL vector product and thus is not explicitly validated. Tile coverage: 4 degrees latitude by 6 degrees longitude File format: GeoTIFF (unsigned byte) Projection: Geographic WGS84 Resolution: 30 m Pixel classifications: DN = 256 : No Data DN = 255 : River DN = 180 : Lake/reservoir DN = 126 : Tidal rivers/delta DN = 86 : Canal DN = 0 : Land/water not connected to the GRWL river network 3) Documentation for the Global River Width from Landsat (GRWL) Vector Product V01.01 This zip file contains 829 ESRI shapefile polylines of river centerlines. Tile coverage: 4 degrees latitude by 6 degrees longitude. Projection: Geographic WGS84 Resolution: 30 m At each GRWL measurement location, the shapefile contains the following attributes: 1. utm_east: UTM Easting (UTM Zone is given in tile file name; meters) 2. utm_north: UTM Northing (UTM Zone is given in tile file name; meters) 3. width_m: wetted width of river (meters) note: width_m == 1 indicates NA (no width data along the centerline) 4. nchannels: braiding index (-) 5. segmentID: unique ID of river segment in each tile 6. segmentInd: Index of each observation in each segment. Not sorted by upstream or downstream 7. lakeflag: integer specifying if observation is located on a river (lakeflag=0), lake/reservoir (lakeflag=1), tidal river (lakeflag=2), or canal (lakeflag=3). 8. lon: Longitude (decimal degrees) 9. lat: Latitude (decimal degrees) 10. elev: Elevation (meters) – sampled from the Hydro1k DEM

若您在研究中使用全球河流宽度数据集（Global River Width from Landsat, GRWL），请引用如下文献：Allen与Pavelsky（2018）《全球河流与溪流覆盖范围》，发表于《科学》（Science）期刊。DOI链接：https://doi.org/10.1126/science.aat0636。本长期存档库包含三类文件：1）简化版GRWL矢量产品：GRWL_summaryStats_V01.01.zip；2）GRWL掩膜（栅格）：GRWL_mask_V01.01.zip；3）GRWL矢量产品：GRWL_vector_V01.01.zip。其他补充数据：- 单个GRWL瓦片的位置地图：Shapefile下载；- 按流域划分的河流与溪流表面积统计（对应Allen & Pavelsky, 2018中的图4）：Shapefile下载。

1）全球河流宽度数据集（GRWL）简化矢量产品V01.01说明
本压缩包包含单条ESRI形状文件（ESRI shapefile）格式的河流中心线折线要素。投影坐标系：地理坐标系WGS84。本文件为原始GRWL矢量产品的简化版本（详见下文第3项）。相较于原始GRWL矢量数据集，本产品体积更小、更易于处理，多数GRWL用户会优先选择此简化版本。该简化矢量产品通过精简折线几何形状，并沿每个折线分段计算统计摘要，从而减少了要素顶点与属性的数量。折线分段大致为每条支流汇口之间的线段。针对每个折线分段，该形状文件包含如下属性：
1. width_min：该分段在平均流量下的河流宽度测量最小值（单位：米）
2. width_med：该分段在平均流量下的河流宽度测量中位数（单位：米）
3. width_mean：该分段在平均流量下的河流宽度测量平均值（单位：米）
4. width_max：该分段在平均流量下的河流宽度测量最大值（单位：米）
5. width_sd：该分段在平均流量下的河流宽度测量标准差（单位：米）
6. lakeflag：整数标识，用于指定分段所在的地物类型：lakeflag=0代表河流，lakeflag=1代表湖泊/水库，lakeflag=2代表潮汐河流，lakeflag=3代表运河。该属性的精准度以全球河流宽度数据集（GRWL）矢量产品V01.01（即下文第3项产品）为准。
8. nSegPx：该分段包含的像素数量（单位：像素数）
9. Shape_Leng：该分段的长度（单位：千米）

2）全球河流宽度数据集（GRWL）掩膜产品V01.01说明
本压缩包包含830幅平均流量下的水体掩膜GeoTIFF瓦片。该数据库的构建过程详见Allen与Pavelsky（2018）发表于《科学》的《全球河流与溪流覆盖范围》一文。GRWL掩膜是GRWL矢量产品生产过程中的中间产物，因此未经过专门的验证。瓦片覆盖范围：纬度4°×经度6°。文件格式：GeoTIFF（无符号字节型）。投影坐标系：地理坐标系WGS84。分辨率：30米。像素分类规则如下：
DN=256：无数据
DN=255：河流
DN=180：湖泊/水库
DN=126：潮汐河流/三角洲
DN=86：运河
DN=0：与GRWL河网无连接的陆地/水体

3）全球河流宽度数据集（GRWL）矢量产品V01.01说明
本压缩包包含829条ESRI形状文件（ESRI shapefile）格式的河流中心线折线要素。瓦片覆盖范围：纬度4°×经度6°。投影坐标系：地理坐标系WGS84。分辨率：30米。在每个GRWL测量点位，该形状文件包含如下属性：
1. utm_east：UTM东向坐标（UTM带号在瓦片文件名中注明；单位：米）
2. utm_north：UTM北向坐标（UTM带号在瓦片文件名中注明；单位：米）
3. width_m：河流的过水宽度（单位：米）。注：width_m=1表示无有效数据（该中心线无宽度测量值）
4. nchannels：辫状河指数（无单位）
5. segmentID：每个瓦片内河流分段的唯一标识符
6. segmentInd：每个分段内各观测值的索引，未按上游或下游方向排序
7. lakeflag：整数标识，用于指定观测点位所在的地物类型：lakeflag=0代表河流，lakeflag=1代表湖泊/水库，lakeflag=2代表潮汐河流，lakeflag=3代表运河
8. lon：经度（十进制度数）
9. lat：纬度（十进制度数）
10. elev：海拔高程（单位：米）—— 数据取自Hydro1k数字高程模型

搜集汇总

背景与挑战

背景概述

该数据集包含全球河流和溪流的宽度、位置及类型信息，基于Landsat卫星图像，提供30米分辨率的矢量和水掩膜数据。适用于水文、环境科学及河流生态系统研究。