Geofabric Surface Network - V2.1

## **Abstract** \n\nThis dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied.\n\n\n\nThe Geofabric Surface Network product provides a set of related feature classes to be used as the basis for production of consistent hydrological surface stream network analysis. This product contains a topographically consistent representation of the (major) surface water features of Australia (excluding external territories). Primarily, these are natural surface hydrology features but the product also contains some man-made features (notably reservoirs and other hydrographic features). The Geofabric Surface Network product is based upon the input from ANUDEM Derived Streams V1.1.2 (ANUDEM Streams) which is the vectorised version of the nine second ANUDEM derived raster steams product. The product is related to, but distinct from, the stream network contained in the Geofabric Surface Cartography product. The network product represents the flow direction of streams over the surface of the terrain, based on the GEODATA Nine Second Digital Elevation Model (DEM-9S) Version 3. This product is more generalised than the Geofabric Surface Cartography and represents the main channels of the stream, particularly in areas where streams are heavily anabranched or disconnected. In addition, the stream connectivity represents a stream flow over the terrain, regardless of the presence of a corresponding Geofabric Surface Cartography stream segment. This means that the Geofabric Surface Cartography product may represent a stream as an interrupted or intermittent feature, whereas this product represents the same stream as a continuous connected feature. That is, the path that a stream would take (according to the terrain model) if sufficient water were available for flow. This product is fully topologically correct which means that all the stream segments flow in the correct direction. It also has full connectivity based on the flow of water across a terrain model. This product contains six feature types including: Waterbody, Network Stream, Network Node, Catchment, Network Connectivity (Upstream) and Network Connectivity (Downstream).\n\n## **Dataset History** \n\nGeofabric Surface Network is part of a suite of Geofabric products produced by the Australian Bureau of Meteorology. The geometry of this product is largely derived from the ANUDEM Derived Streams V1.1.2 (ANUDEM Streams). It consists of water bodies such as swamps, reservoirs, lakes, etc as derived from AusHydro V1, as well as the stream lines and stream line connectors through these water bodies. The ANUDEM Streams are firstly vectorised to be usable in vector line feature format and are then informed and modified by the coincident locations of the AHGFMappedStream feature class. The features are organised into specific feature class subtypes, based upon both the inputs from the AusHydro V1.7.2 and their behaviour within the AHGF Network Stream relationships. All of the AHGFNetworkStream and AHGFWaterbody features participate in the connected stream flow topology. \n\n\n\nThis product also contains the AHGFCatchment features that are derived from the National Catchment Boundaries V1.1.4. The AGHFCatchment feature class consist of the lowest level stream flow catchments based upon the inputs from ANUDEM Streams. The catchment boundaries are based upon a single AHGFNetworkStream extent over GEODATA National 9 Second DEM grid. These catchments form the basis of aggregated catchment boundaries, either by Contracted Nodes or by Pfafstetter ID Levels.\n\n\n\nAll of these features participate in the connected stream flow topology.\n\n\n\nProcessing steps: \n\n1. ANUDEM Streams dataset is received and loaded into the Geofabric development GIS environment. \n\n2. Feature classes from ANUDEM Streams are recomposed into composited Geofabric Feature Dataset Feature Classes in the Geofabric Maintenance Geodatabase.\n\n3. Re-composited feature classes in the Geofabric Maintenance Geodatabase Feature Dataset are assigned unique Hydro-IDs using ESRI ArcHydro for Surface Water (ArcHydro: 1.4.0.180 and ApFramework: 3.1.0.84).\n\n4. Feature classes from the Geofabric Maintenance Geodatabase Feature Dataset are extracted and reassigned to the Geofabric Surface Network Feature Dataset within the Geofabric Surface Network Geodatabase.\n\n\n\nA complete set of data mappings, from input source data to Geofabric Products, is included in the Geofabric Product Guide, Appendices.\n\n## **Dataset Citation** \n\nBureau of Meteorology (2011) Geofabric Surface Network - V2.1. Bioregional Assessment Source Dataset. Viewed 13 March 2019, http://data.bioregionalassessments.gov.au/dataset/ed3acf9b-888c-4d53-b376-ecab89781651.

## **摘要**

本数据集及其元数据声明由第三方提交至生物区域评估计划（Bioregional Assessment Programme），本文档按原始提交版本呈现。

地理基底地表网络（Geofabric Surface Network）产品提供一组相关要素类，可作为构建一致性水文地表河网分析的基础。本产品以地形一致的方式呈现澳大利亚（不含海外领地）的（主要）地表水体要素。这些要素以自然地表水文特征为主，但也包含部分人工设施（尤其是水库及其他水文地理要素）。地理基底地表网络产品基于ANUDEM派生河流V1.1.2版（ANUDEM Streams）的输入数据，该数据集是9秒分辨率ANUDEM派生栅格河流产品的矢量化版本。本产品与地理基底地表制图（Geofabric Surface Cartography）产品中的河网相关，但又与之有所区别。

本网络产品基于GEODATA 9秒数字高程模型（DEM-9S）V3版，表征地形表面上的河流流向。相较于地理基底地表制图产品，本产品更为概化，着重表征河流主河道，尤其适用于存在大量分流或河道断开的区域。此外，本产品的河网连通性表征地形上的水流路径，无论是否存在对应的地理基底地表制图河道要素。这意味着地理基底地表制图产品可能将河流表示为间断或间歇性要素，而本产品则将同一河流表示为连续连通的要素。换言之，本产品表征的是在地形模型中，当有足够水量时河流应遵循的流动路径。本产品具备完全拓扑正确性，即所有河道段均遵循正确的流向；同时基于地形模型的水流逻辑实现了完整的连通性。本产品包含6类要素，分别为：水体（Waterbody）、河网河段（Network Stream）、河网节点（Network Node）、集水区（Catchment）、上游河网连通性（Network Connectivity (Upstream)）以及下游河网连通性（Network Connectivity (Downstream)）。

## **数据集历史**

地理基底地表网络是澳大利亚气象局（Australian Bureau of Meteorology）出品的一系列地理基底产品中的一员。本产品的几何形态主要源自ANUDEM派生河流V1.1.2版（ANUDEM Streams）。其包含从AusHydro V1中提取的沼泽、水库、湖泊等水体要素，以及贯穿这些水体的河道线与河道连接线。ANUDEM派生河流首先被矢量化为矢量线要素格式，随后通过AHGFMappedStream要素类的重合位置进行信息补充与修正。基于AusHydro V1.7.2的输入数据以及AHGF河网河段关系中的要素行为特征，本产品的要素被归类为特定的要素子类。所有AHGF河网河段（AHGFNetworkStream）与AHGF水体（AHGFWaterbody）要素均纳入连通河流水流拓扑关系中。

本产品还包含从全国集水区边界V1.1.4版（National Catchment Boundaries V1.1.4）提取的AHGF集水区（AHGFCatchment）要素。AHGF集水区要素类包含基于ANUDEM派生河流数据生成的最低层级河流水流集水区。集水区边界基于GEODATA全国9秒数字高程模型网格上的单个AHGF河网河段范围划定。这些集水区可通过收缩节点（Contracted Nodes）或普发斯特特（Pfafstetter）ID层级进行聚合，形成更高层级的集水区边界。

所有上述要素均纳入连通河流水流拓扑关系中。

处理流程如下：

1. 接收ANUDEM派生河流数据集并加载至地理基底开发GIS环境中。
2. 将ANUDEM派生河流的要素类重新整合为地理基底维护地理数据库中的复合地理基底要素数据集要素类。
3. 利用ESRI地表水专用ArcHydro工具（ArcHydro: 1.4.0.180 与 ApFramework: 3.1.0.84）为地理基底维护地理数据库要素数据集中的重新整合要素类分配唯一的水文ID（Hydro-ID）。
4. 提取地理基底维护地理数据库要素数据集中的要素类，并重新分配至地理基底地表网络地理数据库中的地理基底地表网络要素数据集。

从输入源数据到地理基底产品的完整数据映射表已收录于《地理基底产品指南》附录中。

## **数据集引用**

澳大利亚气象局（2011）《地理基底地表网络V2.1版》，生物区域评估源数据集。2019年3月13日查阅，http://data.bioregionalassessments.gov.au/dataset/ed3acf9b-888c-4d53-b376-ecab89781651。