NASA has released version 2 of the Shuttle Radar Topography Mission digital topographic data (also known as the "finished" version). Version 2 is the result of a substantial editing effort by the National Geospatial Intelligence Agency and exhibits well-defined water bodies and coastlines and the absence of spikes and wells (single pixel errors), although some areas of missing data ('voids') are still present. The Version 2 directory also contains the vector coastline mask derived by NGA during the editing, called the SRTM Water Body Data (SWBD), in ESRI Shapefile format. [Summary provided by NASA.]

Culminating more than four years of processing data, NASA and the National Geospatial-Intelligence Agency (NGA) have completed Earth's most extensive global topographic map. The mission is a collaboration among NASA, NGA, and the German and Italian space agencies. For 11 days in February 2000, the space shuttle Endeavour conducted the Shuttle Radar Topography Mission (SRTM) using C-Band and X-Band interferometric synthetic aperture radars to acquire topographic data over 80% of the Earth's land mass, creating the first-ever near-global data set of land elevations. This data was used to produce topographic maps (digital elevation maps) 30 times as precise as the best global maps used today. The SRTM system gathered data at the rate of 40,000 per minute over land. They reveal for the first time large, detailed swaths of Earth's topography previously obscured by persistent cloudiness. The data will benefit scientists, engineers, government agencies and the public with an ever-growing array of uses. The SRTM radar system mapped Earth from 56 degrees south to 60 degrees north of the equator. The resolution of the publicly available data is three arc-seconds (1/1,200th of a degree of latitude and longitude, about 295 feet, at Earth's equator). The final data release covers Australia and New Zealand in unprecedented uniform detail. It also covers more than 1,000 islands comprising much of Polynesia and Melanesia in the South Pacific, as well as islands in the South Indian and Atlantic oceans. SRTM data are being used for applications ranging from land use planning to "virtual" Earth exploration. Currently, the mission's homepage "http://www.jpl.nasa.gov/srtm" provides direct access to recently obtained earth images. The Shuttle Radar Topography Mission C-band data for North America and South America are available to the public. A list of complete public data set is available at "http://www2.jpl.nasa.gov/srtm/dataprod.htm" The data specifications are within the following parameters: 30-meter X 30-meter spatial sampling with 16 meter absolute vertical height accuracy, 10-meter relative vertical height accuracy, and 20-meter absolute horizontal circular accuracy. From the JPL Mission Products Summary, "http://www.jpl.nasa.gov/srtm/dataprelimdescriptions.html". The primary products of the SRTM mission are the digital elevation maps of most of the Earth's surface. Visualized images of these maps are available for viewing online. Below you will find descriptions of the types of images that are being generated: Radar Image Radar Image with Color as Height Radar Image with Color Wrapped Fringes -Shaded Relief Perspective View with B/W Radar Image Overlaid Perspective View with Radar Image Overlaid, Color as Height Perspective View of Shaded Relief Perspective View with Landsat or other Image Overlaid Contour Map - B/W with Contour Lines Stereo Pair Anaglypgh The SRTM radar contained two types of antenna panels, C-band and X-band. The near-global topographic maps of Earth called Digital Elevation Models (DEMs) are made from the C-band radar data. These data were processed at the Jet Propulsion Laboratory and are being distributed through the United States Geological Survey's EROS Data Center. Data from the X-band radar are used to create slightly higher resolution DEMs but without the global coverage of the C-band radar. The SRTM X-band radar data are being processed and distributed by the German Aerospace Center, DLR.

The Shuttle Radar Topography Mission (SRTM) was flown aboard the space shuttle Endeavour February 11-22, 2000. The National Aeronautics and Space Administration (NASA) and the National Geospatial-Intelligence Agency (NGA) participated in an international project to acquire radar data which were used to create the first near-global set of land elevations. The radars used during the SRTM mission were actually developed and flown on two Endeavour missions in 1994. The C-band Spaceborne Imaging Radar and the X-Band Synthetic Aperture Radar (X-SAR) hardware were used on board the space shuttle in April and October 1994 to gather data about Earth's environment. The technology was modified for the SRTM mission to collect interferometric radar, which compared two radar images or signals taken at slightly different angles. This mission used single-pass interferometry, which acquired two signals at the same time by using two different radar antennas. An antenna located on board the space shuttle collected one data set and the other data set was collected by an antenna located at the end of a 60-meter mast that extended from the shuttle. Differences between the two signals allowed for the calculation of surface elevation. Endeavour orbited Earth 16 times each day during the 11-day mission, completing 176 orbits. SRTM successfully collected radar data over 80% of the Earth's land surface between 60° north and 56° south latitude with data points posted every 1 arc-second (approximately 30 meters). Two resolutions of finished grade SRTM data are available through EarthExplorer from the collection held in the USGS EROS archive: 1 arc-second (approximately 30-meter) high resolution elevation data offer worldwide coverage of void filled data at a resolution of 1 arc-second (30 meters) and provide open distribution of this high-resolution global data set. Some tiles may still contain voids. The SRTM 1 Arc-Second Global (30 meters) data set will be released in phases starting September 24, 2014. Users should check the coverage map in EarthExplorer to verify if their area of interest is available. 3 arc-second (approximately 90-meter) medium resolution elevation data are available for global coverage. The 3 arc-second data were resampled using cubic convolution interpolation for regions between 60° north and 56° south latitude. [Summary provided by the USGS.]

The Shuttle Radar Topography Mission (SRTM) obtained elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of Earth. SRTM consisted of a specially modified radar system that flew onboard the Space Shuttle Endeavour during an 11-day mission in February of 2000. SRTM is an international project spearheaded by the National Geospatial-Intelligence Agency (NGA) and the National Aeronautics and Space Administration (NASA).

Version 3: Elimination of the voids in the NASA SRTM DEM was the primary goal of a project under the NASA MEaSUREs (Making Earth System Data Records for Use in Research Environments) Program. Ultimately this was achieved by filling the voids with elevation data primarily from the ASTER GDEM2 (Global Digital Elevation Model Version 2) and secondarily from the USGS GMTED2010 elevation model or the USGS National Elevation Dataset (NED). For more information on this dataset visit the LP DAAC NASA Shuttle Radar Topography Mission Global 3 arc second page.

The Shuttle Radar Topography Mission (SRTM, see Farr et al. 2007) digital elevation data is an international research effort that obtained digital elevation models on a near-global scale. This SRTM V3 product (SRTM Plus) is provided by NASA JPL at a resolution of 1 arc-second (approximately 30m). This dataset has undergone a void-filling process using open-source data (ASTER GDEM2, GMTED2010, and NED), as opposed to other versions that contain voids or have been void-filled with commercial sources. For more information on the different versions see the SRTM Quick Guide. Documentation: User's Guide General Documentation Algorithm Theoretical Basis Document (ATBD)

The Shuttle Radar Topography Mission (SRTM) was a partnership between NASA and the National Geospatial-Intelligence Agency (NGA). Flown aboard the NASA Space Shuttle Endeavour (11-22 February 2000), SRTM fulfilled its mission to map the world in three dimensions. The USGS is under agreement with NGA and NASA's Jet Propulsion Laboratory to distribute SRTM elevation products derived from the C-band radar data. SRTM utilized interferometric C-band Spaceborne Imaging Radar to generate elevation data over 80 percent of the Earth's land surface. Global SRTM data at a resolution of 1 arc-second have been edited to delineate and flatten water bodies, better define coastlines, remove spikes and wells, and fill small voids. Larger areas of missing data or voids were filled by the NGA using interpolation algorithms in conjunction with other sources of elevation data. The SRTM 1 Arc-Second Global data offer worldwide coverage of void filled data at a resolution of 1 arc-second (30 meters) and provide open distribution of this high-resolution global data set.

Dataset downloadable for free on the website of the Consultative Group on International Agricultural Research - Consortium for Spatial Information (CGIAR-CSI). The SRTM digital elevation data provided on this site has been processed to fill data voids, and to facilitate it’s ease of use by a wide group of potential users. Digital elevation models (DEM) for the entire globe, covering all of the countries of the world, are available for download on this site. The SRTM 90m DEM’s have a resolution of 90m at the equator, and are provided in mosaiced 5 deg x 5 deg tiles for easy download and use. All are produced from a seamless dataset to allow easy mosaicing. These are available in both ArcInfo ASCII and GeoTiff format to facilitate their ease of use in a variety of image processing and GIS applications. Data can be downloaded using a browser or accessed directly from the ftp site.

The Shuttle Radar Topography Mission (SRTM) successfully collected Interferometric Synthetic Aperture Radar (IFSAR) data over 80 percent of the landmass of the Earth between 60 degrees North and 56 degrees South latitudes in February 2000. The mission was co-sponsored by the National Aeronautics and Space Administration (NASA) and National Geospatial-Intelligence Agency (NGA). NASA's Jet Propulsion Laboratory (JPL) performed preliminary processing of SRTM data and forwarded partially finished data directly to NGA for finishing by NGA's contractors and subsequent monthly deliveries to the NGA Digital Products Data Wharehouse (DPDW). All the data products delivered by the contractors conform to the NGA SRTM products and the NGA Digital Terrain Elevation Data (DTED) to the Earth Resources Observation & Science (EROS) Center. The DPDW ingests the SRTM data products, checks them for formatting errors, loads the SRTM DTED into the NGA data distribution system, and ships the public domain SRTM DTED to the U.S. Geological Survey (USGS) Earth Resources Observation & Science (EROS) Center. Two resolutions of finished grade SRTM data are available through EarthExplorer from the collection held in the USGS EROS archive: 1 arc-second (approximately 30-meter) high resolution elevation data are only available for the United States. 3 arc-second (approximately 90-meter) medium resolution elevation data are available for global coverage. The 3 arc-second data were resampled using cubic convolution interpolation for regions between 60° north and 56° south latitude. [Summary provided by the USGS.]

SRTM data are also available globally at 1 arc second resolution (SRTMGL1.003) through the Data Pool (https://e4ftl01.cr.usgs.gov/MEASURES/SRTMGL1.003/) or from EarthExplorer where it is listed as NASA SRTM3 SRTMGL1. Please sign in with NASA Earthdata Login Credentials to download data from the NASA LP DAAC Collections. These datasets require login on both NASA Earthdata and USGS EarthExplorer systems to access data. After you create your account, you will also need to “authorize” the LP DAAC Data Pool application. On the Profile page in your Earthdata account you will need to select My Applications. On that page make sure the LP DAAC Data Pool is listed. If it isn't then select Authorize More Applications. In the dialog box type in LP DAAC Data Pool and click Search For Applications. Select Approve when presented with the lpdaac_datapool. Keep everything checked but you can uncheck the Yes, I would like to be notified box. Select Authorize and the LP DAAC Data Pool should be added to your Approved Applications. You might benefit from using the AppEEARS tool. · o AppEEARS landing page: https://lpdaacsvc.cr.usgs.gov/appeears/ · o The users will need and https://urs.earthdata.nasa.gov/?_ga=2.148606453.334533939.1615325167-1213876668.1613754504. Click or tap if you trust this link.">Earthdata Login · o Getting started instructions can be found here: https://lpdaacsvc.cr.usgs.gov/appeears/help Previously available here: Digital Elevation Model of Ireland, from NASA's Shuttle Radar Topography Mission (SRTM), sampled at 3 arc second intervals in latitude & longitude (about every 90m) in heightmap (.HGT) format.''Latitudes & longitudes are referenced to WGS84, heights are in meters referenced to the WGS84/EGM96 geoid.'' Please see the linked pdf files for further documentation.''A QGIS project for the hgt files is also attached.

UPDATE: Data no longer available from this page. All non-working links have been removed (19/7/21)

Users must follow instructions below from NASA to access data:

SRTM data are also available globally at 1 arc second resolution (SRTMGL1.003) through the Data Pool (https://e4ftl01.cr.usgs.gov/MEASURES/SRTMGL1.003/) or from EarthExplorer where it is listed as NASA SRTM3 SRTMGL1. Please sign in with NASA Earthdata Login Credentials to download data from the NASA LP DAAC Collections. These datasets require login on both NASA Earthdata and USGS EarthExplorer systems to access data. After you create your account, you will also need to “authorize” the LP DAAC Data Pool application. On the Profile page in your Earthdata account you will need to select My Applications. On that page make sure the LP DAAC Data Pool is listed. If it isn't then select Authorize More Applications. In the dialog box type in LP DAAC Data Pool and click Search For Applications. Select Approve when presented with the lpdaac_datapool. Keep everything checked but you can uncheck the Yes, I would like to be notified box. Select Authorize and the LP DAAC Data Pool should be added to your Approved Applications. You might benefit from using the AppEEARS tool. ·
o AppEEARS landing page: https://lpdaacsvc.cr.usgs.gov/appeears/

·
o The users will need and https://urs.earthdata.nasa.gov/?_ga=2.148606453.334533939.1615325167-1213876668.1613754504. Click or tap if you trust this link.">Earthdata Login

·
o Getting started instructions can be found here: https://lpdaacsvc.cr.usgs.gov/appeears/help

Previously available here: Digital Elevation Model of Ireland, from NASA's Shuttle Radar Topography Mission (SRTM), sampled at 3 arc second intervals in latitude & longitude (about every 90m) in heightmap (.HGT) format.''Latitudes & longitudes are referenced to WGS84, heights are in meters referenced to the WGS84/EGM96 geoid.'' Please see the linked pdf files for further documentation.''A QGIS project for the hgt files is also attached.

The Shuttle Radar Topography Mission (SRTM, DTS-99) from February 11 to 22, 2000 was an US-German-Italian effort to produce a first global digital elevation model (DEM). The German Aerospace Center (DLR) and the Italian Space Agency (ASI) complemented the US C-band Synthetic Aperture Radar (SAR) payload of NASA/JPL with an additional X-SAR instrument. The SRTM X-SAR DEM was generated at DLR from this instrument’s data using radar interferometry technique. The data was acquired simultaneously from aboard the Space Shuttle Endeavor employing two SAR antennas, one inside the Space Shuttle’s cargo bay, the other at the end of a 60 m extension pole. A substantial portion of the global land surface between 60° northern and 58° southern latitude was covered. As the orbit flown and imaging period of the SRTM mission had been optimised for the US C-band system, the German-Italian X-SAR with narrower aperture angle imaged data only along roughly 50 km wide orbital ground traces. So, the dataset available shows a grid-like coverage. The original SRTM X-SAR DTED DEMs have been merged to 10° by 10° tiles, converted to GeoTIFF format and packaged into zip-archives. Each zip-file contains the DEM dataset, the corresponding height error map (HEM), a quicklook png-image, a kml-overlay and a readme document. The filename of the zip-archive specifies the bottom left coordinate of each tile. The zip-archives can be downloaded via the EOC Download Service.

For more information see: https://geoservice.dlr.de/resources/licenses/srtm_xsar/DLR_SRTM_XSAR_ReadMe.pdf

Note: This version of the SRTM GL1 dataset is provided in a WGS84 ellipsoidal vertical datum. This is a non-standard version of the SRTM dataset that is often used for InSAR analysis. This dataset was converted from the orthometric version using the EGM96 geoid model available here. For additional conversion details feel free to contact us.

The Shuttle Radar Topography Mission (SRTM) obtained elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of Earth. SRTM consisted of a specially modified radar system that flew onboard the Space Shuttle Endeavour during an 11-day mission in February of 2000. SRTM is an international project spearheaded by the National Geospatial-Intelligence Agency (NGA) and the National Aeronautics and Space Administration (NASA).

Version 3: Elimination of the voids in the NASA SRTM DEM was the primary goal of a project under the NASA MEaSUREs (Making Earth System Data Records for Use in Research Environments) Program. Ultimately this was achieved by filling the voids with elevation data primarily from the ASTER GDEM2 (Global Digital Elevation Model Version 2) and secondarily from the USGS GMTED2010 elevation model or the USGS National Elevation Dataset (NED). NASA SRTM V3.0 three-arc-second data are provided in two forms: (1) by three-by-three averaging of the one arc-second samples, and (2) by extracting the middle sample of those same three-by-three samples. For more information on this dataset visit the LP DAAC NASA Shuttle Radar Topography Mission Global 1 arc second page.

SRTM data are also available globally at 1 arc second resolution (SRTMGL1.003) through the Data Pool (https://e4ftl01.cr.usgs.gov/MEASURES/SRTMGL1.003/) or from EarthExplorer where it is listed as NASA SRTM3 SRTMGL1. Please sign in with NASA Earthdata Login Credentials to download data from the NASA LP DAAC Collections. These datasets require login on both NASA Earthdata and USGS EarthExplorer systems to access data. After you create your account, you will also need to “authorize” the LP DAAC Data Pool application. On the Profile page in your Earthdata account you will need to select My Applications. On that page make sure the LP DAAC Data Pool is listed. If it isn't then select Authorize More Applications. In the dialog box type in LP DAAC Data Pool and click Search For Applications. Select Approve when presented with the lpdaac_datapool. Keep everything checked but you can uncheck the Yes, I would like to be notified box. Select Authorize and the LP DAAC Data Pool should be added to your Approved Applications. You might benefit from using the AppEEARS tool. · o AppEEARS landing page: https://lpdaacsvc.cr.usgs.gov/appeears/ · o The users will need and https://urs.earthdata.nasa.gov/?_ga=2.148606453.334533939.1615325167-1213876668.1613754504. Click or tap if you trust this link.">Earthdata Login · o Getting started instructions can be found here: https://lpdaacsvc.cr.usgs.gov/appeears/help Previously available here: Digital Elevation Model of Ireland, from NASA's Shuttle Radar Topography Mission (SRTM), sampled at 3 arc second intervals in latitude & longitude (about every 90m) in heightmap (.HGT) format.''Latitudes & longitudes are referenced to WGS84, heights are in meters referenced to the WGS84/EGM96 geoid.'' Please see the linked pdf files for further documentation.''A QGIS project for the hgt files is also attached.

A global 1-km resolution land surface digital elevation model (DEM) derived from U.S. Geological Survey (USGS) 30 arc-second SRTM30 gridded DEM data created from the NASA Shuttle Radar Topography Mission (SRTM). GTOPO30 data are used for high latitudes where SRTM data are not available. For a grayscale hillshade image layer of this dataset, see "world_srtm30plus_dem1km_hillshade" in the distribution links listed in the metadata.

The 3 second (~90m) Shuttle Radar Topographic Mission (SRTM) Digital Elevation Model (DEM) version 1.0 was derived from resampling the 1 arc second (~30m) gridded DEM (ANZCW0703013355). The DEM represents ground surface topography, and excludes vegetation features. The dataset was derived from the 1 second Digital Surface Model (DSM; ANZCW0703013336) by automatically removing vegetation offsets identified using several vegetation maps and directly from the DSM. The 1 second product provides substantial improvements in the quality and consistency of the data relative to the original SRTM data, but is not free from artefacts. Man-made structures such as urban areas and power line towers have not been treated. The removal of vegetation effects has produced satisfactory results over most of the continent and areas with defects are identified in the quality assessment layers distributed with the data and described in the User Guide (Geoscience Australia and CSIRO Land & Water, 2010). A full description of the methods is in progress (Read et al., in prep; Gallant et al., in prep). The 3 second DEM was produced for use by government and the public under Creative Commons attribution.

The Shuttle Radar Topography Mission data at 30meters resolution for Tanzania. Referenced tiles were mosaicked and clipped to the extent of the country.

This dataset contains WebMercator tiles which contain gray-scale shaded relief (hill shades), and nothing else. The tiles have a resolution of 256×256px, suitable for web mapping libraries such as Leaflet. The hill shades are generated from SRTM altitude data, which cover the land area between 60° northern and 58° southern latitude, and which lies in the public domain. Map material without political or infrastructural features can be desirable, for example, in use cases where historical data is visualized on a map. The concrete motivation for generating this map material was the Dhimmis & Muslims project (project page, home page, GitHub, DaRUS dataset), which analyzed peaceful coexistence of religious groups in the medieval Middle East. A particular goal with creating the dataset was to have map material available under a permissive license for screenshots and publications, instead of relying on proprietary mapping services such as Mapbox. Teaser image: The hillshades of Cyprus on zoom level 9. This image is hosted externally by GitHub, but is also present in the repository as teaser.png. Coverage. The dataset covers zoom level 0 (entire world in one tile) to 12 (entire world in 4096×4096 tiles). The total size of the dataset is 22,369,621 tiles. However, of those, 19,753,304 tiles (88.3%) are empty, either because the landscape there is fully flat (i.e., on water), or because they lie fully outside the latitude range covered by the SRTM altitude data. The empty tiles are not stored. Instead, a singular placeholder file is stored in the repository, alongside a list of the empty tiles. During extraction, the placeholder empty tile can be symbolically linked in the file system to all the places where it is needed. The total size of the non-empty tiles is about 103GB. Files. Besides the placeholder file and the list of empty tiles, the repository also contains a manifest file. This file lists all non-empty tiles by the ZIP file they are contained in. The tiles themselves are grouped into ZIP files by the following schema: All tiles from levels 0 to 5 are contained in one ZIP file. All tiles of level N, N≥6 are contained in a ZIP file which is named after the tile of level N-6 (block level) that contains the tile in question, named tiles_.zip. Hence, all tiles of level 6 are contained in a singular ZIP file named tiles_6_0_0_0.zip. The tiles of level 7 are split up into four group ZIP files named tiles_7_1_{0,1}_{0,1}.zip, the tiles of level 8 into 16 group ZIP files named tiles_8_2_{0..3}_{0..3}.zip, and so on. Both the manifest file and the commands to generate the distribution of tiles on ZIP files can be generated using the linked software repository. Usage. The tile ZIP files can be downloaded and extracted. By serving the extracted directory structure in a web server, a slippy map tile server can be created. The linked software repository also contains a command-line utility that generates the required shell commands to download the ZIP files, extract them, and softlink (ln -s) the empty tiles to the appropriate places. This command-line utility can also optionally read in a GeoJSON file of an area of interest. In this case, only tiles within that area are downloaded in a higher zoom level, whereas tiles completely outside the area are only downloaded to a lower zoom level; both zoom levels are also configurable. See the documentation in the repository and the command-line utility’s help (-h) output for more details.

This service represents a combination of two data products, the DEM_SRTM_1Second dataset and the Australian_Bathymetry_Topography dataset. This service was created to support the CO2SAP (Co2 Storage application) Project to create a transect elevation graph within the application. This data is not available as a dataset for download as a Geoscience Australia product. The DEM_SRTM_1Second service represents the National Digital Elevation Model (DEM) 1 Second product derived from the National DEM SRTM 1 Second. The DEM represents ground surface topography, with vegetation features removed using an automatic process supported by several vegetation maps. eCat record 72759. The Australian_Bathymetry_Topography service describes the bathymetry dataset of the Australian Exclusive Economic Zone and beyond. Bathymetry data was compiled by Geoscience Australia from multibeam and single beam data (derived from multiple sources), Australian Hydrographic Service (AHS) Laser Airborne Depth Sounding (LADS) data, Royal Australian Navy (RAN) fairsheets, the General Bathymetric Chart of the Oceans (GEBCO) bathymetric model, the 2 arc minute ETOPO (Smith and Sandwell, 1997) and 1 arc minute ETOPO satellite derived bathymetry (Amante and Eakins, 2008). Topographic data (onshore data) is based on the revised Australian 0.0025dd topography grid (Geoscience Australia, 2008), the 0.0025dd New Zealand topography grid (Geographx, 2008) and the 90m SRTM DEM (Jarvis et al, 2008). eCat record 67703. IMPORTANT INFORMATION For data within this service that lays out of the Australian boundary the following needs to be considered. This grid is not suitable for use as an aid to navigation, or to replace any products produced by the Australian Hydrographic Service. Geoscience Australia produces the 0.0025dd bathymetric grid of Australia specifically to provide regional and local broad scale context for scientific and industry projects, and public education. The 0.0025dd grid size is, in many regions of this grid, far in excess of the optimal grid size for some of the input data used. On parts of the continental shelf it may be possible to produce grids at higher resolution, especially where LADS or multibeam surveys exist. However these surveys typically only cover small areas and hence do not warrant the production of a regional scale grid at less than 0.0025dd. There are a number of bathymetric datasets that have not been included in this grid for various reasons.

Data represents the Shuttle Radar Topography Mission (SRTM) 30 metres image for Malawi.These SRTM was created through mosaicking tiles and clippingto the extent of the country.

This dataset corresponds to a reformatting of the SRTM30_PLUS digital elevation dataset from 33 NetCDF files into a single GeoTiff for use in GIS applications. No other modifications to the data were done. The rest of this metadata describes the original SRTM30_PLUS dataset itself.

This dataset is a 30-arc second resolution global topography/bathymetry grid (SRTM30_PLUS) developed from a wide variety of data sources. Land and ice topography comes from the SRTM30 and ICESat topography, respectively. Ocean bathymetry is based on a new satellite-gravity model where the gravity-to-topography ratio is calibrated using 298 million edited soundings. The main contribution of this dataset is the compilation and editing of the raw soundings, which come from NOAA, individual scientists, SIO, NGA, JAMSTEC, IFREMER, GEBCO, and NAVOCEANO.

The SRTM30_PLUS dataset developed by Scripps Institute Of Oceanography, University of California San Diego (UCSD).

Land data are based on the 1-km averages of topography derived from the USGS SRTM30 grided DEM data product created with data from the NASA Shuttle Radar Topography Mission. GTOPO30 data are used for high latitudes where SRTM data are not available.

Ocean data are based on the Smith and Sandwell global 1-minute grid between latitudes +/- 81 degrees. Higher resolution grids have been added from the LDEO Ridge Multibeam Synthesis Project, the JAMSTEC Data Site for Research Cruises, and the NGDC Coastal Relief Model. Arctic bathymetry is from the International Bathymetric Chart of the Oceans (IBCAO) [Jakobsson et al., 2003].

This data consists of 33 files of global topography in the same format as the SRTM30 products distributed by the USGS EROS data center. The grid resolution is 30 second which is roughly one kilometer. In addition the global data are also available in a single large file ready for GMT and as 33 NetCDF files. The eAtlas has also merged and formatted the data as a single GeoTiff file with overviews (1.6 GB).

The pixel-registered data are stored in 33 files with names corresponding to the upper left corner of the array shown below. The data are also merged into a single large (1.9 Gbyte, 2-byte integer) file as well as smaller 1-minute and 2-minute netcdf versions. Matching files of source identification number are available for determining the data source for every pixel.

This new version (v8.0) includes all of the multibeam bathymetry data collected by U.S. research vessels over the past three decades including 287 Scripps expeditions from research vessels Washington, Melville and Revelle. UCSD undergraduate student Alexis Shakas processed all the U.S. multibeam data and then worked with Google researchers on the global integration.

The data is available from UCSD FTP server as 33 NetCDF files and from the eAtlas as a merged GeoTiff.

If you are after high resolution bathymetry/elevation data for regional areas please check the related links.

Reference, sounding data: Becker, J. J., D. T. Sandwell, W. H. F. Smith, J. Braud, B. Binder, J. Depner, D. Fabre, J. Factor, S. Ingalls, S-H. Kim, R. Ladner, K. Marks, S. Nelson, A. Pharaoh, R. Trimmer, J. Von Rosenberg, G. Wallace, P. Weatherall., Global Bathymetry and Elevation Data at 30 Arc Seconds Resolution: SRTM30_PLUS, Marine Geodesy, 32:4, 355-371, 2009. http://topex.ucsd.edu/sandwell/publications/124_MG_Becker.pdf

Reference, gravity data: Sandwell, D. T., and W. H. F. Smith, Global marine gravity from retracked Geosat and ERS-1 altimetry: Ridge Segmentation versus spreading rate, J. Geophys. Res., 114, B01411, doi:10.1029/2008JB006008, 2009. http://dx.doi.org/10.1029/2008JB006008

eAtlas Processing:

A set of Batch scripts were developed to perform the conversion of the data from NetCDF to GeoTiff and the generation of the hillshading. This processing was based on the GDAL command line tools. Full details of the processing can be found in the downloadable Scripts associated with this dataset.

Data Location:

This dataset is filed in the eAtlas enduring data repository at: data\NERP-TE\13.1_eAtlas\World_UCSD_SRTM30-plus