The map is available in different levels of accuracy:
- VMAP Level 0 is based on the Operational Navigation Chart (ONC) on a scale of 1: 1,000,000 and is freely available,
- VMAP Level 1 is based on the scale 1: 250,000 and is largely reserved for military purposes.
Frames and Accuracy
- The horizontal datum is WGS84 , with an accuracy between approximately 2000 and 4000 meters
- The vertical date is Mean Sea Level (MSL, height above sea level ), accuracy between 150 ( contour lines ) and 30 meters (height points)
The VMAP-0 data is divided into four areas (North America, South America and Africa, Europe and northern Asia, Southeast Asia and Australia). Each data package is zipped a good 200 MB. The VMAP-1 data are divided into 234 zones, 57 of which are freely available.
The VMAP is divided into various topics (coverages), which in turn contain sub-categories:
- Political Entities
- Place Names
- Data quality
- Elevation (height information)
- Hydrography ( hydrography )
- Physiography ( morphology of the earth's surface)
- Vegetation (vegetation)
The VMAP is stored in the Vector Product Format (VPF), which is divided into directories and binary files. The VPF is described in the military standard MIL-STD-2407.
The detailed VMAP description is documented in specification MIL-PRF-89039, supplemented by the second amendment of June 27, 2001
- NGA portal with specifications for spatial data including VMAP0 (MIL-PRF-89039) and VPF (MIL-STD-2407)
- Entry in the GIS lexicon
- Downloads of the free VMAP-1 data
- Processing of VMAP-0 data with free GIS software: SRTM and VMAP0 data in OGR and GRASS . GRASS Newsletter , 3: 2-6, 2005 (M. Neteler)