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 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.

Urban land area below 5m is the percentage of total land where the urban land elevation is 5 meters or less.

This dataset is a categorical mapping of estimated mean building heights, by Census block group, in shapefile format for the conterminous United States. The data were derived from the NASA Shuttle Radar Topography Mission, which collected “first return” (top of canopy and buildings) radar data at 30-m resolution in February, 2000 aboard the Space Shuttle Endeavor. These data were processed here to estimate building heights nationally, and then aggregated to block group boundaries. The block groups were then categorized into six classes, ranging from “Low” to “Very High”, based on the mean and standard deviation breakpoints of the data. The data were evaluated in several ways, to include comparing them to a reference dataset of 85,000 buildings for the city of San Francisco for accuracy assessment and to provide contextual definitions for the categories.

Elevation Studio Group Creative Joint Stock Company Export Import Data. Follow the Eximpedia platform for HS code, importer-exporter records, and customs shipment details.

This dataset contains digital terrain data that describes the topography of the area under study at 90m resolution based on SRTM 90m Digital Elevation Data from the CGIAR-CSI (Consultative Group on International Agricultural Research - Consortium for Spatial Information). Gro for GooD: Groundwater Risk Management for Growth and Development, https://upgro.org/consortium/gro-for-good/

Topography. 30 metre Digital Elevation Model (DEM). This layer was merged, clipped and reprojected by CeRDI (Federation University Australia). A coloured-relief map was generated and rendered as an RGB GeoTIFF. Elevation data originally sourced from Geoscience Australia's Elevation Information System (ELVIS).

The National Digital Elevation Model (DEM) 1 Second Hydrologically Enforced product, derived from the National DEM SRTM 1 Second and National Watercourses, lakes and Reservoirs.

The Global Ecosystem Dynamics Investigation (GEDI) mission aims to characterize ecosystem structure and dynamics to enable radically improved quantification and understanding of the Earth’s carbon cycle and biodiversity. The GEDI instrument produces high resolution laser ranging observations of the 3-dimensional structure of the Earth. GEDI is attached to the International Space Station (ISS) and collects data globally between 51.6° N and 51.6° S latitudes at the highest resolution and densest sampling of any light detection and ranging (lidar) instrument in orbit to date. Each GEDI Version 2 granule encompasses one-fourth of an ISS orbit and includes georeferenced metadata to allow for spatial querying and subsetting.The GEDI instrument was removed from the ISS and placed into storage on March 17, 2023. No data were acquired during the hibernation period from March 17, 2023, to April 24, 2024. GEDI has since been reinstalled on the ISS and resumed operations as of April 26, 2024.The purpose of the GEDI Level 2A Geolocated Elevation and Height Metrics product (GEDI02_A) is to provide waveform interpretation and extracted products from each GEDI01_B received waveform, including ground elevation, canopy top height, and relative height (RH) metrics. The methodology for generating the GEDI02_A product datasets is adapted from the Land, Vegetation, and Ice Sensor (LVIS) algorithm. The GEDI02_A product is provided in HDF5 format and has a spatial resolution (average footprint) of 25 meters.The GEDI02_A data product contains 156 layers for each of the eight beams, including ground elevation, canopy top height, relative return energy metrics (e.g., canopy vertical structure), and many other interpreted products from the return waveforms. Additional information for the layers can be found in the GEDI Level 2A Dictionary.Known Issues Data acquisition gaps: GEDI data acquisitions were suspended on December 19, 2019 (2019 Day 353) and resumed on January 8, 2020 (2020 Day 8). Incorrect Reference Ground Track (RGT) number in the filename for select GEDI files: GEDI Science Data Products for six orbits on August 7, 2020, and November 12, 2021, had the incorrect RGT number in the filename. There is no impact to the science data, but users should reference this document for the correct RGT numbers. Known Issues: Section 8 of the User Guide provides additional information on known issues.Improvements/Changes from Previous Versions Metadata has been updated to include spatial coordinates. Granule size has been reduced from one full ISS orbit (~5.83 GB) to four segments per orbit (~1.48 GB). Filename has been updated to include segment number and version number. Improved geolocation for an orbital segment. Added elevation from the SRTM digital elevation model for comparison. Modified the method to predict an optimum algorithm setting group per laser shot. Added additional land cover datasets related to phenology, urban infrastructure, and water persistence. Added selected_mode_flag dataset to root beam group using selected algorithm. Removed shots when the laser is not firing.* Modified file name to include segment number and dataset version.

This Web Map is a subset of World Elevatuon GMTED image service.The Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010) dataset provides a 7.5 arcsecond (approximately 250 meter resolution) digital elevation model with world-wide coverage at a resolution suitable for regional to continental scale analyses. Dataset SummaryThis layer provides access to a 250m cell-sized raster created from the Global Multi-resolution Terrain Elevation Data 2010 7.5 arcsecond mean elevation product. The dataset represents a compilation and synthesis of 11 different existing raster data sources. The data were published in 2011 by the USGS and the National Geospatial-Intelligence Agency.The dataset is documented in the publication: Danielson and Gesch. 2011. Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010). U.S. Geological Survey Open-File Report 2011–1073, 26 p.The source data for this layer are available here.This layer is part of a larger collection of landscape layers that you can use to perform a wide variety of mapping and analysis tasks.The Living Atlas of the World provides an easy way to explore the landscape layers and many other beautiful and authoritative maps on hundreds of topics.Geonet is a good resource for learning more about landscape layers and the Living Atlas of the World. To get started see the Living Atlas Discussion Group.The Esri Insider Blog provides an introduction to the Ecophysiographic Mapping project.

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.]

Rural land area below 5m is the percentage of total land where the rural land elevation is 5 meters or less.

Light Detection and Ranging (LiDAR) data was collected by The Geoinformation Group using LiDAR-equipped survey aircraft for the main urban conurbations of England and Wales (including London, Manchester, Birmingham, Liverpool, Newcastle, Edinburgh and Glasgow) as part of the Cities Revealed project, and made available through the Landmap service. The GeoInformation Group (TGG) has processed the data so that they are available as Digital Terrain Models (ground surface only) and Digital Surface/Elevation Models (the ground and all features on it), both geographic databases with height and surface measurement information in the form of regular grids with intervals of 1 or 2 m. In addition, some First Pass and Last Pass data are available. The First Pass data provides height values for the top of the canopy (i.e. buildings, trees etc.) while the Last Pulse data provides height values for the bottom of the canopy and provides information about the shape of the terrain. The data are available in img format. The Joint Information Systems Committee (JISC) funded Landmap service which ran from 2001 to July 2014 collected and hosted a large amount of earth observation data for the majority of the UK, part of which was elevation data. After removal of JISC funding in 2013, the Landmap service is no longer operational, with the data now held at the NEODC. When using the data please also add the following copyright statement: Cities Revealed © The GeoInformation Group yyyy

The ASTER L3 DEM and Orthorectified Images form a multi-file product that contains both the Digital Elevation Model (DEM), and the Orthorectified Image products. Each product delivery includes one DEM data file, and fifteen orthorectified data files in GeoTIFF format.

ASTER SWIR data acquired from April 2008 to the present exhibit anomalous saturation of values and anomalous striping. This effect is also present for some prior acquisition periods. Please refer to the ASTER SWIR User Advisory Document (https://lpdaac.usgs.gov/sites/default/files/public/aster/docs/ASTER_SWIR_User_Advisory_July%2018_08.pdf) for more details.

ASTER DEM

The ASTER Digital Elevation Model (DEM) product is generated using Bands 3N (nadir-viewing) and 3B (backward-viewing) of an ASTER Level-1A image acquired by the Visible Near Infrared (VNIR) sensor. The VNIR subsystem includes two independent telescopes. Together, they produce stereoscopic data. The spectral range of the Band 3 stereo pair is between 0.78 and 0.86 µm with a base-to-height ratio of 0.6, and an intersection angle of about 27.7. There is a time lag of approximately one minute between the acquisition of the nadir and backward-viewing images.

ASTER DEM is a single-band product with 30 meter horizontal postings that is geodetically referenced to the UTM coordinate system, and referenced to the Earth's geoid using the EGM96 geopotential model. The precision of the meets or exceeds accuracy specifications set for the ASTER relative DEMs by the Algorithm Theoretical Basis Document (ATBD). Validation testing has shown that the accuracy of the DEMs is frequently better than 25 meters RMSE xyz.

ASTER Orthorectified Images

The ASTER Orthorectified Image products contain imagery transformed from a perspective projection to an orthogonal one. An orthorectified image possesses the geometric characteristics of a map, with near-vertical views for every location. These products are terrain-corrected, provide radiometrically calibrated radiance, and are mapped to the Universal Transverse Mercator coordinate system. The inputs include the following: an ASTER Level-1A Reconstructed Unprocessed Instrument data set; georeferencing information from the ASTER instrument's and Terra platform's ephemeris and attitude data; and an ASTER-derived digital elevation model (DEM). The output product includes fifteen orthorectified ASTER Level-1B calibrated radiance images, one per Band.

Differences between an ASTER Level-1B data set and ASTER Orthorectified Images

 - ASTER Level-1B data consist of calibrated radiance in a path-oriented
  UTM projection, whereas ASTER orthorectified images are presented in
  a north-up UTM projection. 

 - ASTER orthorectified images possess the geometric characteristics of a
  map with near-vertical views for every location, and they also are
  terrain-corrected.

 - ASTER L1B image dimensions for each of the three sensor systems (VNIR,
  SWIR, and TIR) are different because of their different spatial
  resolutions; those image dimensions remain constant from one L1B scene
  to another. However, ASTER orthorectified image dimensions can vary
  from scene to scene. This is because the image dimensions of the ASTER
  Digital Elevation Model (DEM) used in the orthorectification process
  can vary, and the DEMs image dimensions define the output dimensions
  for each of the three sensors orthorectified images.

 - The ASTER Level-1B data set is provided in a single multi-file packaged
  Hierarchical Data Format (HDF) with specific Earth Observing System
  (EOS) conventions. The ASTER orthorectified image file format is
  GeoTIFF. The file includes fifteen orthorectified ASTER Level-1B 
  calibrated radiance images, one for each Band. These image files are 
  compressed and provided to the user in a single zip file. 

V003 data set release date: 2007-03-05

Data Set Characteristics: Area: ~60 km x 60 km Image Dimensions: 2500 rows x 2500 columns File Size: ~191 MB Units: w/m2/sr/µm Projection: Universal Transverse Mercator (UTM) Data Format: GeoTIFF Data Fields: 1

The VIIRS/NPP Day/Night Band Moderate Resolution Terrain-Corrected Geolocation 6-Min L1 Swath 750m Near Real Time (NRT) product, short-name VNP03DNB_NRT includes the geolocation fields that are calculated for VIIRS day-night band (DNB) Line of sight (LOS) for all orbits at the nominal resolution of 750 m. The locations and ancillary information correspond to the intersection of the centers of each Field of View (FOV) from 16 detectors in the DNB on the Earth's surface. A digital terrain model is used to model the Earth's surface. The main inputs are the spacecraft attitude and orbit ephemeris data, the instrument telemetry and the digital elevation model. The geolocation fields contained within the VNP03DNB Geolocation files include geodetic latitude, longitude, surface height above the geoid, solar and lunar zenith and azimuth angles, lunar phase angle and illumination fraction, satellite zenith and azimuth angles, and a land/water mask for each 750m sample. Additional information is included in the header to enable the calculation of the approximate location of the center of the detectors for any of the VIIRS bands. This product is used as input by subsequent VIIRS day/night band products, particularly those produced by the Land team.

Acquisition of Light Detection and Ranging (LiDAR) elevation data was for the Hurricane and Storm Damage Risk Reduction System (HSDRRS). In February 2012, USACE, Contracting Division contracted with The Atlantic Group to provide acquisition of Light Detection and Ranging (LiDAR) elevation data in the Hurricane and Storm Damage Risk Reduction System, St. Charles, Jefferson, Orleans, St. Bernard...

Yearly effective energy and mass transfer (EEMT) (MJ m−2 yr−1) was calculated for the Valles Calders, upper part of the Jemez River basin by summing the 12 monthly values. Effective energy and mass flux varies seasonally, especially in the desert southwestern United States where contemporary climate includes a bimodal precipitation distribution that concentrates in winter (rain or snow depending on elevation) and summer monsoon periods. This seasonality of EEMT flux into the upper soil surface can be estimated by calculating EEMT on a monthly basis as constrained by solar radiation (Rs), temperature (T), precipitation (PPT), and the vapor pressure deficit (VPD): EEMT = f(Rs,T,PPT,VPD). Here we used a multiple linear regression model to calculate the monthly EEMT that accounts for VPD, PPT, and locally modified T across the terrain surface. These EEMT calculations were made using data from the PRISM Climate Group at Oregon State University (www.prismclimate.org). Climate data are provided at an 800-m spatial resolution for input precipitation and minimum and maximum temperature normals and at a 4000-m spatial resolution for dew-point temperature (Daly et al., 2002). The PRISM climate data, however, do not account for localized variation in EEMT that results from smaller spatial scale changes in slope and aspect as occurs within catchments. To address this issue, these data were then combined with 10-m digital elevation maps to compute the effects of local slope and aspect on incoming solar radiation and hence locally modified temperature (Yang et al., 2007). Monthly average dew-point temperatures were computed using 10 yr of monthly data (2000–2009) and converted to vapor pressure. Precipitation, temperature, and dew-point data were resampled on a 10-m grid using spline interpolation. Monthly solar radiation data (direct and diffuse) were computed using ArcGIS Solar Analyst extension (ESRI, Redlands, CA) and 10-m elevation data (USGS National Elevation Dataset [NED] 1/3 Arc-Second downloaded from the National Map Seamless Server at seamless.usgs.gov). Locally modified temperature was used to compute the saturated vapor pressure, and the local VPD was estimated as the difference between the saturated and actual vapor pressures. The regression model was derived using the ISOHYS climate data set comprised of approximately 30-yr average monthly means for more than 300 weather stations spanning all latitudes and longitudes (IAEA).

Abstract

This dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied.

The GEODATA 9 Second DEM (DEM-9S) Version 3 is a grid of ground level elevation points covering the whole of Australia, with a grid spacing of 9 seconds in longitude and latitude (approximately 250 metres) in the GDA94 coordinate system. The 9 Second Flow Direction Grid (D8-9S) is a corresponding grid describing the principal directions of surface drainage across the whole of Australia.

Version 3 of the DEM-9S was calculated by Version 5.2.2 of the ANUDEM procedure (Hutchinson 2007) from comprehensively revised and augmented national GEODATA TOPO-250K (TOPO-250K) topographic source data (AUSLIG 1992, Geoscience Australia 2003, Geoscience Australia 2006). The

source data included revised versions of TOPO-250K elevation points, streamlines, cliff lines and waterbodies, trigonometric points from the National Geodetic Database and additional elevation, streamline and sink point data digitised by the Fenner School from 1:100K source material. Version

5.2.2 of the ANUDEM procedure incorporates major upgrades to the modelling of streamlines, lakes, cliff lines and the coastline.

The 9 Second Flow Direction Grid (D8-9S) has been released for the first time, with Version 3. This grid was calculated by the ANUDEM procedure as it calculated the DEM-9S. It incorporates the data streamline structure and describes the drainage structure continent-wide. It can be used to delineate

streamlines and associated catchment boundaries for the DEM-9S. This is particularly useful in low relief areas where drainage structure is not reliably defined by the DEM elevations alone.

The comprehensive revisions and additions to the source data for the DEM-9S Version 3 were completed over a period of 3 years by the Fenner School and Geoscience Australia. This built on the substantial period of source data revision and algorithmic development by the Fenner School over the last 15 years. Comprehensive quality assurance of the DEM-9S and the D8-9S was performed jointly by the Fenner School and Geoscience Australia. The revised version of the ANUDEM elevation gridding procedure was developed and implemented by Professor Michael Hutchinson of the Fenner School.

The DEM-9S Version 3 is a model of the terrain in which each data point represents the approximate elevation at the centre of each 9 second by 9 second cell. The density and positional accuracy of the source point elevation data generalises the local terrain, resulting in limited representation of some high

points. Version 3 incorporates the improvements made in Version 2 by including with the source data the national trigonometric points from the National Geodetic Data Base.

The representation of abrupt changes in landform has been comprehensively upgraded in Version 3 by incorporating, for the first time, the TOPO-250K national cliff line data and by upgrading the modelling of cliff lines by the ANUDEM procedure to minimise conflicts between streamlines and cliff lines. The

upgraded procedure maximises the accuracy of the representation of surface shape within the limits imposed by the 9 second grid spacing.

Of central importance for the accurate representation of surface drainage structure is the upgrading of the modelling of streamlines by ANUDEM. This improves the positional accuracy of streamlines and explicitly incorporates, also for the first time, the extensive distributary streamline networks that occur in low relief areas of the Australian continent. ANUDEM has also been upgraded to improve the positional accuracy of the coastline and to ensure a smooth transition between land and seabed away from areas with coastal cliffs.

Dataset History

Dataset history was not supplied with the original metadata. The following history was written by the Bioregional Assessment team.

See: Chapter 2 - "The Development of the 9 Second DEM" within the attached User Guide PDF.

\* Early National Digital Elevation Models

\* 9 Second DEM Version 1

\* 9 Second DEM Version 2

\* 9 Second DEM Version 3

This chapter recounts the development over the last three decades of national topographic data, and the associated development of the ANUDEM elevation gridding procedure, leading to the successive versions of the 9 Second DEM.

Further information can be found at http://www.ga.gov.au/metadata-gateway/metadata/record/66006/

Dataset Citation

Geoscience Australia (2008) GEODATA 9 second DEM and D8: Digital Elevation Model Version 3 and Flow Direction Grid 2008. Bioregional Assessment Source Dataset. Viewed 13 March 2019, http://data.bioregionalassessments.gov.au/dataset/ebcf6ca2-513a-4ec7-9323-73508c5d7b93.

Overview:

This layer has been modified from the GMTED 90m resolution datasets to produce a 1km layer to match other MOOD covariates. The data are minimum elevation in metres plus 1000 to remove negative values.

File naming scheme:

vcmi30grdp1k.TIF and vcmi30grdp1k.TFW

Projection + EPSG code:Latitude-Longitude/WGS84 (EPSG: 4326)

Spatial extent:Extent -24.0000000000000000,-38.5000000000000000 : 110.9999999999999432,86.9999999999999432

Spatial resolution:0.0083333 deg (approx. 1000 m)

Accuracy:

Based on World Geodetic System 1984 ensemble (EPSG:6326), which has a limited accuracy of at best 2 meters.

Pixel values:unit: meter

Source:

Copernicus Digital Elevation Model (DEM) for Europe derived from Copernicus Global 30 meter DEM dataset

Software used:ArcMap 10.8

License: CC-BY-SA 4.0

Processed by:ERGO (Environmental Research Group Oxford) https://ergoonline.co.uk/ for the H2020 MOOD project

The CGIAR-CSI GeoPortal is able to provide SRTM 90m Digital Elevation Data for the entire world. The SRTM digital elevation data, produced by NASA originally, is a major breakthrough in digital mapping of the world, and provides a major advance in the accessibility of high quality elevation data for large portions of the tropics and other areas of the developing world. 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. This data is provided in an effort to promote the use of geospatial science and applications for sustainable development and resource conservation in the developing world. 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.

This dataset is a digital elevation model of the Ivotuk site from the Snow, Shrubs, and Weather Group. It contains two files, an ASCII data file and a .jpg image of the data.