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

This dataset is the Mossman River catchment 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 Mossman 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工具生成的莫斯曼河（Mossman River）流域边界数据集，其河流定义阈值为5000个栅格单元。河流定义基于由30米分辨率数字高程模型（digital elevation model, DEM）生成的汇流累积栅格，相关参考文献为S. R. Januchowski、R. L. Pressey、J. VanDerWal与A. Edwards于2010年发表的《Characterizing errors in digital elevation models and estimating the financial costs of accuracy》，该论文已被《International Journal of Geographical Information Science》录用待刊。

数据集用途：
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。本次子流域划分基于30米分辨率数字高程模型完成，因此适用于区域尺度的流域管理相关研究与决策问题。

数据集编制历程：
本数据集的莫斯曼河流域边界仍由ArcHydro 1.3工具生成，河流定义阈值为5000个栅格单元。首先通过ArcHydro生成流域栅格，随后将栅格形式的流域转换为矢量多边形要素类：将流域栅格中具有相同栅格编码的相邻栅格单元合并为单一区域，并对其边界进行矢量化。随后自动合并单栅格多边形以及矢量化过程中作为伪影产生的孤立多边形，最终每个流域仅保留一个多边形要素。

本次研究的流域栅格由汇流累积栅格生成，而汇流累积栅格则基于30米分辨率数字高程模型制作。本研究使用的数字高程模型由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/）的点数据融合生成。该模型的参数与精度信息详见S. R. Januchowski、R. L. Pressey、J. VanDerWal与A. Edwards于2010年发表的《Characterizing errors in digital elevation models and estimating the financial costs of accuracy》，该论文发表于《International Journal of Geographical Information Science》待刊。其中地形等高线数据的平面与垂直定位精度均为20米；该数字高程模型在高地形起伏区域的垂直精度为17.53米，在低地形起伏区域的垂直精度为6.31米。