Barron River Subcatchments - Barron catchments from a 30 m digital elevation model

This dataset is the Barron River subcatchment boundaries created using ArcHydro 1.3, with a stream definition threshold of 5,000 cells. Stream definition was determined from a flow accumulation grid which was generated from a 30 m digital elevation model (S. R. Januchowski, R. L. Pressey, J. VanDerWal and A. Edwards. 2010. Characterizing errors in digital elevation models and estimating the financial costs of accuracy. International Journal of Geographical Information Science. in press.) Purpose: This data set has been designed to inform conservation and management planning and decision making exercise related to freshwater ecosystems. The sub catchments have been delineated from a 30 m digital elevation model, and therefore, are suitable for addressing catchment management questions at a regional scale. History: This dataset is the Barron River catchment boundaries created using ArcHydro 1.3, with a stream definition threshold of 5,000 cells. The catchment grid delineated using ArcHydro was used to convert grid catchments into a catchment polygon feature class. The adjacent cells in the catchment grid that have the same grid code are combined into a single area, whose boundary is vectorized. The single cell polygons and the "orphan" polygons generated as the artefacts of the vectorization process are dissolved automatically, so that at the end of the process there is just one polygon per catchment. The catchment grid was determined from a flow accumulation grid which was generated from a 30 m digital elevation model (DEM). The DEM used in this process was created using a combination of digital topographic contour lines and point data derived from the SRTM high-resolution digital topographic database (http://www2.jpl.nasa.gov/srtm/). The specifications and accuracy of this model are reported in S. R. Januchowski, R. L. Pressey, J. VanDerWal and A. Edwards. 2010. Characterizing errors in digital elevation models and estimating the financial costs of accuracy. International Journal of Geographical Information Science (in press). The topographic contour data had a 20 m positional accuracy (vertical and horizontal).The DEM had a vertical accuracy of 17.53 m in higher-relief areas and 6.31 in low-relief areas.

本数据集为采用ArcHydro 1.3工具生成的巴伦河子汇水区边界，溪流定义阈值为5000个栅格单元。溪流定义基于流量累积栅格确定，该栅格由30米分辨率数字高程模型（digital elevation model, DEM）生成（引用：S. R. Januchowski、R. L. Pressey、J. VanDerWal与A. Edwards，2010年，《Characterizing errors in digital elevation models and estimating the financial costs of accuracy》，《International Journal of Geographical Information Science》，已录用）。

**用途**：本数据集旨在为淡水生态系统相关的保护与管理规划及决策工作提供支撑。本次子汇水区由30米分辨率数字高程模型勾绘而成，因此适用于区域尺度的汇水管理相关研究问题。

**沿革**：本数据集的巴伦河汇水边界由ArcHydro 1.3工具生成，溪流定义阈值为5000个栅格单元。研究中先通过ArcHydro生成汇水栅格，再将汇水栅格转换为汇水多边形要素类。将汇水栅格中具有相同栅格编码的相邻单元格合并为单一区域，并对该区域的边界进行矢量化处理。自动消解栅格矢量化过程中产生的单单元格多边形与“孤立”多边形伪影，最终使每个汇水区仅对应一个多边形。汇水栅格由流量累积栅格生成，而流量累积栅格则基于30米分辨率数字高程模型构建。本次研究所用DEM结合了数字地形等高线数据与源自SRTM高分辨率地形数据库（http://www2.jpl.nasa.gov/srtm/）的点数据生成。该DEM的精度参数已在S. R. Januchowski、R. L. Pressey、J. VanDerWal与A. Edwards 2010年发表于《International Journal of Geographical Information Science》（已录用）的《Characterizing errors in digital elevation models and estimating the financial costs of accuracy》一文中详细说明。其中地形等高线数据的平面与垂直位置精度均为20米；该DEM在高地形起伏区域的垂直精度为17.53米，在低地形起伏区域为6.31米。