Vector Map (VMAP), AKA Vector Smart Map, is a vector-based collection of GIS data covering the earth at various detail levels. Level 0 (low resolution) coverage is global, and is entirely in the public domain. Level 1 (global coverage at medium resolution) is only partly in the public domain.
Description
- Coordinate reference system: Geographic coordinates stored in decimal degrees with southern and western hemispheres using a negative latitude and longitude
Thematic data layers
Features and data attributes are tagged utilizing the international Feature and Attribute Coding Catalogue (FACC).
- major road networks
- railroad networks
- hydrologic drainage systems
- utility networks (cross-country pipelines and communication lines)
- major airports
- elevation contours
- coastlines
- international boundaries
- populated places
- index of geographical names
Levels of resolution
The vector map product comes in three flavors: low resolution (level 0), medium resolution (level 1) and high resolution (level 2).
Level 0 provides worldwide coverage of geo-spatial data and is equivalent to a small scale (1:1,000,000). The data are offered either on CD-ROM or as direct download, as they have been moved to the public domain. Data are structured following the Vector Product Format (VPF).
The entire coverage has been divided into four data sets:
- North America (NOAMER)
- Europe and North Asia (EURNASIA)
- South America, Africa, and Antarctica (SOAMAFR)
- South Asia and Australia (SASAUS).
Level 1 data are equivalent to a medium scale resolution.
- Horizontal accuracy: 125-500m
- Vertical accuracy: 0.5-2m
VMAP Level 1 is divided in 234 geographical tiles. Only 57 of them are currently (2006) available for download from NGA. Amongst the available datasets, coverage can be found for parts of:
- Costa Rica
- Libya
- United States
- Mexico
- Iraq
- Russia
- Panama
- Colombia
- Japan
Level 2 data are equivalent to a large scale resolution.
Debate about availability of data
The U.S.A. Freedom of Information Act and the Electronic Freedom of Information Act guarantee access to virtually all GIS data created by the US government. Following the trend of the United States, much of the VMAP data has been offered to the public domain.
Still many countries consider mapping and cartography a state monopoly; for such countries, the VMAP Level1 data are kept out of the public domain. With the privatization of public agencies, some data are sold for a profit.
Efforts are being made by various public groups towards moving all VMAP1 data to the public domain.
Further steps have been taken (by the Free World Maps Foundation among others) to licence the data under the GNU General Public License while remaining copyrighted, as an alternative to the public domain. This is an ongoing debate (as of 2006), of which the outcome is yet to be seen.
Tools to read and convert VMAP data
- VPFView (V2.1) - developed by NIMA, is available from NGA or USGS (as part of the NIMAMUSE package); this tool can render simple plots and export GIS data to other GIS file formats
- "OGR with OGDI driver": this free software tool can convert VMAP format to standard GIS file formats such as SHAPE, PostGIS etc.
References
Main Reference
http://en.wikipedia.org/wiki/Vector_Map
NGA Home Page
Good Article about vector product format
Vector product format standards
http://www.nga.mil/NGASiteContent/StaticFiles/OCR/vpf_main.pdf
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