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 Administr.ation (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 data provided "as is", there may be missing portions within a DEM-file as well as incorrect elevation information.  Data "holes" can be filled by applying the World 1000m Digital Elevation Model dataset.  DDS, Inc. can also provide the service of filling and smoothing 90 meter DEMs.

Specifications

• Coverage: Entire World
• Source Data:  SRTM (Shuttle Radar Topography Mission)
• Projection: Geographic, WGS84, Arc Seconds
• Resolution: three arc-second (approximately 90 meters)
• Each file is delivered in a 1x1 degree block.  Dataset can be purchased by individual areas (World 90 meter coverage index) or by entire world.
• Media: DVD, Hard-drive

Available Formats

• USGS Standard DEM file format
• ESRI GRID
• ASCII XYZ
• .BIL (Intel or Motorola byte order)
• Client specified format (custom pricing).  Call 303-986-6740 for special requests.

$50 per Area in ArcGrid or .BIL Format (or $150.00 USGS .DEM format)

To order 90m areas, locate the area number using the World 90m coverage index and click on

DDS, Inc. offers the entire World 90m dataset (all available tiles) for all 13 areas for only $500!  The data is sampled at 3 arc second/90 meter resolution.   

• ESRI ArcGRID

• .BIL (Motorola or Intel)

• DEM format- $1,500

The process of DEM creation begins with the scanned, geo-referenced Topographic Map or raster image. Contour Lines from the raster image are extracted, converted to digital vectors and given elevation values. Once a digital image has been fully vectorized, a raster representation of the map is created based on those vector features. Then the hydrographic vector features, such as rivers and lakes are added. The resulting file is then output based on the clients File Format Specifications. 

The benefit to having a custom DEM generated from topo maps is that the resulting resolution can be anywhere between 5-30 meters dependant on the contour intervals on the source document.

Common Uses:

• Surveying and civil engineering

• Mining

• Utilities

• Watershed analysis

• Environmental engineering

• Land reclamation

• Cut-and-fill analysis

GIS Indexes:

Step 1.) Download a coverage index at the scale you require from the above links.

Step 2.) Identify the map areas you need.

Step 3.) Provide us with a list of the "SKU" numbers.  i.e. "QDSP_392-350"

Step 4.) We will research you request and provide you with availability, map source, scale and pricing information.

If you are unsure about which maps you need, we can provide assistance identifying your coverage area.

Digital Data Services, Inc.
voice: 303-986-6740
toll-free: 866-337-7226
email: