Import Drawing - VMAP

VMap data set products use the "vector product format" (vpf) utilized first by the US Defense Mapping Agency and later by its successor, the National Imagery and Mapping Agency (NIMA). They feature a vast number of files organized into libraries. "VMap" is derived from "Vector Smart Map". The Manifold VMAP importer can also handle World Vector Shoreline Plus (WVS+) data as published in "vpf" form.

 

VMAP data set products are produced in several levels of resolution:

 

·      VMap Level 0 - Details similar to 1:1 million-scale or 1:2 million-scale paper charts.

·      VMap Level 1 - Details similar to 1:250,000-scale paper charts.

·      VMap Level 2 - Details similar to 1:50,000-scale and 1:100,000-scale paper charts.

 

VMAP Level 0 is equivalent to the famous Digital Chart of the World with slightly different attribute coding. Some, but not all, VMAP Level 1 data sets are available to the public in the US. VMAP Level 2 may or may not be available to the public. Manifold's VMAP importers read all three VMAP variations.

 

images\dlg_import_vmap_01.gif

 

VMAP data sets are organized as "libraries" that are kept in DHT files. There is no extension to the DHT file, as see above. In the illustration above we open a DHT file on CD number 155 of the VMAP Level 1 collection that cover the entire Earth.

 

images\dlg_import_vmap_02.gif

 

Most VMAP1 files have both a "lib" library and a "rference" library. The lib library contains most of the points, lines and areas while the rference library contains place names and other text labels that will be imported into Manifold as labels.

 

Library

Choose the library within this DHT to be imported.

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Select All - Check all the boxes in the coverages pane.

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Select None - Uncheck all the boxes in the coverages pane.

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Select Inverse - Check all unchecked boxes and uncheck all checked boxes in the coverages pane.

Coverages

A list of layer categories within the library. Most layer categories will import as several drawings.

Import each coverage to separate folder

A good idea to leave checked: will create a new folder in the project into which all of the components from this coverage will be imported. Helps keep the project organized.

Import Fields

Check to import data attributes along with object geometry.

Import Z

Import elevation if provided for an object. Import Z causes an additional drawing to be created filled with points, each of which has a Z coordinate.

 

Tip: The fastest way to check just one box is to first Select None and then check the box desired. The fastest way to check all boxes except one is to first Select All, uncheck that box, and then choose Select Inverse.

 

Typical VMap Contents

 

Data in most VMap data sets are separated into twelve categories that NIMA calls coverages . Although the word "coverage" in legacy GIS usage normally means "layer", in this case the word is used to mean "category of layers." In VMap each coverage contains data related to a particular subject category, for example "Transportation."

 

VMap data sets group coverages within "libraries." A reference library containing four reference coverages is also provided with general information to orient the user. The usual arrangement is that a VMap data set is provided on a CD together with a main DHT file that lists all the libraries on that CD. The reference library contains overview cartographic information showing the very broad area (at low resolution) within which the more detailed libraries on the CD are provided.  

 

VMap Level 0 organizes data sets for the entire world onto four CDs. VMap Level 1 organizes worldwide coverage on over 200 CDs. VMap Level 2, of course, uses many hundreds of CDs. The following VMap 1 coverages are typical of all three VMap versions.

 

Data Library

 

bnd

Boundaries

dq

Data Quality

elev

Elevation

hydro

Hydrography

ind

Industry

phys

Physiography

pop

Population

trans

Transportation

util

Utilities

veg

Vegetation

libref

Library Reference

tileref

Tile Reference

Reference Library

 

libref

Library Reference

dbref

Database Reference

polbnd

Political Entities

placenam

Place Names

 

VMap Import Results

 

images\win_import_vmap.gif

 

Importing most VMap "coverages" results in the automatic import of numerous drawings. For convenience, these are organized into maps that correspond to the "coverage." In the example above, we have imported the bnd "coverage" and so have created a bnd map that includes the various drawings listed.

 

images\sc_import_vmap_01.gif

 

The illustration above shows part of the map in a greatly reduced map window (using camouflage green color for the background, of course!).

 

VMap Data Fields

 

For specific information on the numerous data fields and other data characteristics of VMap data sets, visit NIMA's page at http://www.nima.mil and download the various online publications that describe VMap.

 

See Also

 

See the Example Import a VMAP Level 1 File