Bunger Hills contours

Fifty metre interval contours were derived for cartographic purposes from a Digital Elevation Model (DEM) of the Bunger Hills created using SPOT 5 HRS satellite imagery acquired 17 January 2007. The DEM is described by the metadata record 'Bunger Hills SPOT5 DEM (Digital Elevation Model)' with Entry ID bunger_hills_spot5_dem_gis.The DEM was referenced to Mean Sea Level using Earth Gravitational Model 1996 (EGM96).Estimated accuracies of the DEM (confidence level 90%):planimetric - 15 to 30 metresvertical - 10 metres to 20 metres for slope less than or equal to 20 per centThe DEM should be viewed before using the contours as it has some No Data areas.The contours were created in ArcGIS 10.3 using the following procedure:1 The DEM was resampled using the Resample tool to a cell size of 50 metres using the bilinear technique; 2 The DEM resulting from step 1 was used as an input to the Focal Statistics tool which was used to calculate, for each cell, the mean elevation of a three cell by three cell square neighbourhood;3 The Contour tool was used to create 50 metre interval contours from the DEM resulting from step 2;4 The contours resulting from step 3 were smoothed using the Smooth Line tool with the Paek algorithm and a smoothing tolerance of 50 metres; 5 The contours resulting from step 4 were converted to single part features using the Multipart to Singlepart tool; 6 A topology was created for the contours resulting from step 5 and used to identify contours touching and editing was carried out to correct these errors.

本数据集为制图目的，基于2007年1月17日获取的SPOT 5 HRS卫星影像生成的邦杰丘陵（Bunger Hills）数字高程模型（Digital Elevation Model, DEM），提取得到50米间隔等值线。该DEM的元数据记录为"Bunger Hills SPOT5 DEM (Digital Elevation Model)"，条目ID为bunger_hills_spot5_dem_gis。该DEM采用1996年地球重力模型（Earth Gravitational Model 1996, EGM96）参考至平均海平面。该DEM的估计精度（置信水平90%）如下：平面精度为15至30米；当坡度小于等于20%时，垂直精度为10至20米。使用该等值线前请先查看DEM数据，因其存在部分无数据区域。本次等值线系通过ArcGIS 10.3按照以下流程生成：
1. 使用重采样工具（Resample tool）以双线性插值法将DEM重采样至50米像元大小；
2. 将步骤1生成的DEM作为输入，通过焦点统计工具（Focal Statistics tool）计算每个单元格的3×3方形邻域平均高程；
3. 使用等值线工具（Contour tool）从步骤2生成的DEM中创建50米间隔等值线；
4. 使用采用Paek算法、平滑容差为50米的平滑线工具（Smooth Line tool）对步骤3生成的等值线进行平滑处理；
5. 使用多部件转单部件工具（Multipart to Singlepart tool）将步骤4生成的等值线转换为单部件要素；
6. 为步骤5生成的等值线创建拓扑以识别存在接触的等值线，并通过编辑修正此类错误。