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Coverage

Coverage varies by product type. Below is a summary starting with low cost global data options and finishing with larger-scale (more detailed) mapping options.

Low-cost global data options include:

WVS+ -- World Vector Shoreline Plus 1:250,000 vector data of the World's coastlines and international boundaries

V-MAP 0 -- US military 1:1,000,000 vector mapping

SRTM30 – the earlier GTOPO30 30 arc second (approx. 1km) resolution worldwide DEM (Digital Elevation Model) dataset enhanced with reduced resolution SRTM (Shuttle Radar Topography Mission) where available

Regional data products are a little more expensive, and include options such as:

SRTM3 - Shuttle Radar Topography Mission 3 arc second (aprox. 90m) resolution DEMs. This is the lowest-cost option for DEMs of this level of detail and accuracy, however there are void regions (gaps / holes of missing data, especially prevalent in areas of high relief). In addition, land areas above 60º north and below 56° south latitude weren't mapped.

Circa 1990 30m resolution Landsat 5 and circa 2000 15m resolution Landsat 7 satellite imagery.

1:500,000 US military and / or Russian (Soviet) military topographic maps – as DRGs (Digital Raster Graphics) these are low cost, pricing is higher for other formats.

Country data options generally include 1:50,000 – 1:250,000 digital topographic map data, for some regions such as the Caribbean 1:25,000 data is often available. Please click here for a .pdf listing of topographic map availability by country. These are generally from national mapping agencies, Russian (Soviet) military mapping or US military mapping – US military maps are made by NGA (National Geospatial-Intelligency Agency, established 2003), sometimes in conjunction with US allies / partner countries. NGA was formerly known as NIMA (National Imagery and Mapping Agency, 1996 – 2003) and before that was called the Defense Mapping Agency (DMA 1972 - 1996); there are still some maps in circulation from the Army Map Service (AMS) – anything before that would now be considered “historical” data.

Digital topographic map data can be delivered as DRGs, DEMs and / or vector layers. For areas where suitable topographic maps aren't available, up to 25m resolution DEMs can be generated from ASTER stereo pairs, up to 10m DEMs can be derived from SPOT-5 or TK-350 stereo pairs (contingent upon cloud-free stereo pair imagery availability). Please note that outside of the US digital topographic map data is generally not available at low-cost, but rather has to be custom-produced (although having completed a large number of international projects we now have many areas off-the-shelf).

City / large-scale (detailed) mapping (generally 1:10,000 - 1:25,000) is available for over 1,800 cities worldwide from Russian military mapping sources -- please click here for a complete list. A more limited selection is available from US NGA -- please click here for a complete list. High-resolution satellite imagery such as Ikonos 1m and / or QuickBird 60cm can be used as a more detailed and up-to-date (with the use of GPS GCPs also more accurate) data source -- this option is also more expensive although urban areas or more likely to be in archive which does result in a lower cost and faster turn-around time compared to new image collects, and the QuickBird CitySphere product-line offers low-cost / fast turn-around on up-to-date imagery already ortho-rectified to a high degree of accuracy. High-res DEMs from Ikonos / QuickBird stereo pairs are generally not available off-the-shelf but rather have to be custom generated -- this is an expensive process and there are some limitations to the technology but in some instances it can be an excellent value.

For data selection assistance, please contact us with your area of interest and a description of your project.







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