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VMAP1 Introduction
¤ This page introduces the Vector Map Level 1, and explains some of the ways that you can use this free data in your own mapping projects.
 

As I said in the introduction to the VMAP0 section, it comes as a pleasant surprise to discover that despite secrets and closed access in government circles, there is a huge quantity of mapping data available to anyone, free of charge. This data has complete word coverage, and an astonishing range of data types all gathered together in one package. However, in the case of VMAP1 all is not quite so simple. Is the whole dataset de-classified and in the public domain ? Supposedly. However, in actual fact, NIMA have not released the full datasets to the public. To find out about VMAP1, and what's available to download, read on...

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About VMAP1

Vector Map Level 1 product resolution is based on 1:250,000 map scale source, i.e. 1cm=2.5km, and is 4 times the resolution of VMAP0. It is based primarily on the vectorized versions of 1:250,000 scale NIMA Joint Operations Graphics (JOGs) - nearly 10,000 sheets.

Both VMAP0 and VMAP1 are structured similarly, and contain all the standard topographic vector data types familiar to GIS users. Data content includes 10 thematic layers: boundaries and coastlines; elevation and contour lines; road and rail networks; hydrography; utility networks; vegetation cover; and so on. These themes are arranged in over 100 vector layers of information, with mass numbers of features, attributes, and geographic names appropriate to their respective scales.

The horizontal datum for this VMap product is WGS84. The vertical datum for this VMap product is mean sea level (MSL). The unit of measure for VMap is metric. The geographic extent of the VMap Level 1 product is global and consists of multiple regional databases. VMap Level 1 data from standard DMA source products are derived from the feature content defined in the associated military specification VMAP_89033 and allied appendix, available for download as .pdf files from NIMA Publications. Data gaps between a VMap Level 1 library may exist due to absence of data. VMap Level 1 products are organized into thematic layers. Each VMap thematic layer is stored as a single coverage within a VPF library. There are two reference coverages and ten thematic coverages in the data library level.

The VMAP1 data is divided into a rather complex global mosaic of 234 geographic zones, with each available on a single CD-ROM. However at the present time, NIMA are only releasing 57 selected areas of the VMAP1 dataset, even though the whole dataset has been de-classified, is in the public domain, and could be made available via FTP at minimum cost. Some of the excuses given include the protection of cartographic monopolies of it's overseas partners, that it is not ready for the public to see it, that their security office has not approved it, and that NIMA is afraid the public might "misuse" it. They are currently ignoring FOIA (Freedom Of Information Act) petitions to release the data. There are even a number of organisations offering to host the data if NIMA does not wish to provide sufficient FTP facilities; so far this offer has not been taken up. If you would like to find out more about this, or learn how to attempt a request under the Freedom Of Information Act, visit Here or Here. Other resources can be located via the Google Search Engine.

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VMAP1
 
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