Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010)

The U.S. Geological Survey (USGS) and the National Geospatial-Intelligence Agency (NGA) have collaborated on the development of a notably enhanced global elevation model named the Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010) that replaces GTOPO30 as the elevation dataset of choice for global and continental scale applications. GMTED2010 provides a new level of detail in global topographic data. The GMTED2010 product suite contains seven new raster elevation products for each of the 30-, 15-, and 7.5-arc-second spatial resolutions and incorporates the current best available global elevation data. The new elevation products have been produced using the following aggregation methods: minimum elevation, maximum elevation, mean elevation, median elevation, standard deviation of elevation, systematic subsample, and breakline emphasis. Metadata have also been produced to identify the source and attributes of all the input elevation data used to derive the output products. This new product suite provides global coverage of all land areas from latitude 84 degrees N to 56 degrees S for most products, and coverage from 84 degrees N to 90 degrees S for several products. Some areas, namely Greenland and Antarctica, do not have data available at 15- and 7.5- arc-second resolution. The 30-arc-second layer will only include the mean elevation and systematic subsample. Many of these products will be suitable for various regional continental-scale land cover mapping, extraction of drainage features for hydrologic modeling, and geometric and radiometric correction of medium and coarse resolution satellite image data. The global aggregated vertical accuracy of GMTED2010 can be summarized in terms of the resolution and Root Mean Square Error (RMSE) of the products with respect to a global set of control points (estimated global accuracy of 6 m RMSE) provided by NGA. At 30 arc-seconds, the GMTED2010 RMSE range is between 25 and 42 meters; at 15 arc-seconds, the RMSE range is between 29 and 32 meters; and at 7.5 arc-seconds, the RMSE range is between 26 and 30 meters. GMTED2010 is a major improvement in consistency and vertical accuracy over GTOPO30, which has a 66 m RMSE globally compared to the same NGA control points. In areas where new sources of higher resolution data were available, the GMTED2010 products are substantially better than the aggregated global statistics; however, large areas still exist, particularly above 60 degrees North latitude that lack good elevation data. As new data become available, especially in areas that have poor coverage in the current model, it is hoped that new versions of GMTED2010 might be generated and thus gradually improve the global model.

美国地质调查局（U.S. Geological Survey, USGS）与国家地理空间情报局（National Geospatial-Intelligence Agency, NGA）联合研发了一款性能显著提升的全球高程模型——全球多分辨率地形高程数据2010（Global Multi-resolution Terrain Elevation Data 2010, GMTED2010），该模型取代GTOPO30，成为全球及洲际尺度应用的首选高程数据集。GMTED2010实现了全球地形数据细节呈现的新水准，其产品套件包含7种全新栅格高程产品，分别对应30角秒、15角秒与7.5角秒三种空间分辨率，整合了当前可获取的最佳全球高程数据。新型高程产品采用以下聚合方法生成：最小高程、最大高程、平均高程、中位高程、高程标准差、系统子采样以及断裂线增强。同步生成的元数据可用于标识所有用于推导输出产品的输入高程数据的来源与属性。该新型产品套件的多数产品可覆盖北纬84度至南纬56度的全部陆地范围，另有部分产品可覆盖北纬84度至南纬90度的区域；格陵兰岛与南极洲部分区域暂不支持15角秒和7.5角秒分辨率的数据产品，且30角秒图层仅提供平均高程与系统子采样两种产品。此类产品中的多数可应用于区域级洲际尺度的土地覆盖制图、水文建模所需的排水特征提取，以及中低分辨率卫星影像的几何与辐射校正。GMTED2010的全球聚合垂直精度可通过产品分辨率与均方根误差（Root Mean Square Error, RMSE）进行表征，其评估基准为NGA提供的全球控制点集（估计全球精度为6米均方根误差）。其中，30角秒分辨率产品的RMSE范围为25至42米；15角秒分辨率产品的RMSE范围为29至32米；7.5角秒分辨率产品的RMSE范围为26至30米。相较于采用同一NGA控制点集评估、全球RMSE为66米的GTOPO30，GMTED2010在数据一致性与垂直精度上均实现了重大提升。在有更高分辨率新数据可用的区域，GMTED2010产品的表现远优于聚合后的全球统计结果；但仍有大片区域（尤其是北纬60度以北地区）缺乏优质高程数据。随着新数据的持续获取，特别是当前模型覆盖不足的区域，未来有望推出GMTED2010的更新版本，逐步完善这一全球高程模型。