Shulou(Shulou.com)06/03 Report--

SRTMDLR SRTM X-band data: DLR is the abbreviation of German Aerospace Center. 2000 when the space shuttle Endeavour carried out SRTM (Space Shuttle Radar Topographic Mapping Mission), Germans also used their own radar to measure global terrain data. DLR uses higher precision radar test (X band), which brings higher precision than Americans (C band). But it is only elevation data that covers the whole world in a mesh (that is, there is no DLR data in some places). In 2011, the Germans released the download of this data with an accuracy of 1 corner second (1 arc second), relative elevation accuracy of 6 meters and absolute accuracy of 16 meters. You can download: https://centaurus.caf.dlr.de:8443/eoweb-ng/index2.html here.

At the end of 2014, the US government released the highest resolution SRTM DEM to the public. The spatial resolution of this 1-arc-second global digital elevation model is about 30 meters. It covers most parts of the world with an absolute vertical height accuracy of less than 16 meters.

The Germans are currently carrying out higher-precision topographic mapping missions (TanDEM-X and TerraSAR-X double-star observations) to measure higher-precision global data, this time covering the whole world, which is considerable for civilian use. SRTM C-band data, observed by NASA NASA at 2000 using radar measurements on the space shuttle Endeavour, is the most frequently used elevation data in the past, covering areas within 60 degrees north and south latitudes of the world. There are two kinds of data: SRTM1 and SRTM3, that is, the accuracy of 1 second and 3 seconds respectively, and the corresponding accuracy is 30 meters and 90 meters. The elevation data used by Google Earth is SRTM3. The publicly available coverage of the Chinese area is only 90 meters accurate. Images of the Chinese Academy of Sciences can be downloaded. Aster gdem

GDEM . The data are based on observations from NASA's new-generation Earth observation satellite, Terra. The data covers all land areas between latitude 83 °N and latitude 83 °S. This is the most extensive coverage of high-precision global elevation data. The first version of the data was released in 2009, and at present, the Chinese Academy of Sciences has mirror data to download. The release of gdem-v2 data in October 2011 is a revision of previous gdem data, which is available for download on the Japanese Space Agency's website.

GMTED2010 data, provided by USGS of the United States Geological Survey and NGA of the National Geospatial Intelligence Agency. From its README file, it is a further optimization and development of USGS's GTOPO30, but the accuracy of this data is not considerable, only 30 seconds, 15 seconds and 7.5 seconds, and the corresponding highest accuracy is 250m. On USGS, it only covers the elevation data of the United States. According to its introduction, the accuracy of 1 second is 1 second and the accuracy is 3 seconds. In some areas, there are also 1 seconds and 9 seconds, that is, the accuracy reaches the level of 3 meters, which is considerable. JAXA's Global ALOS 3D World

ALOS is an earth observation satellite of Japan. The ALOS satellite carries three sensors: panchromatic remote sensing stereo mapper (PRISM), mainly used for digital elevation mapping, advanced visible and near infrared radiometer-2 (AVNIR-2) for accurate land observation, and phased array L-band synthetic aperture radar (PALSAR) for all-weather and all-weather land observation.

ALOS World 3D is a 30m resolution digital surface model (DSM) captured by the Japan Aerospace Exploration Agency (JAXA). The DSM is open to the public.

Optical radar Light Detection and Ranging (LiDAR)

Several free data sources

Open TopographyUSGS Earth ExplorerUnited States Interagency Elevation InventoryNOAA Digital CoastLIDAR OnlineNational Ecological Observatory Network-NEON

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