Documentation

vmap0data

Read selected data from Vector Map Level 0

Syntax

struct = vmap0data(library,latlim,lonlim,theme,topolevel)
struct = vmap0data(devicename,library, ...)
[struct1, struct2, ...] = vmap0data(...,{topolevel1,topolevel2,...})

Description

struct = vmap0data(library,latlim,lonlim,theme,topolevel) reads the data for the specified theme and topology level directly from the VMAP0 CD-ROM. There are four CDs, one for each of the libraries: 'NOAMER' (North America), 'SASAUS' (Southern Asia and Australia), 'EURNASIA' (Europe and Northern Asia), and 'SOAMAFR' (South America and Africa). The desired theme is specified by a two-letter code string. A list of valid codes is displayed when an invalid code, such as '?', is entered. topolevel defines the type of data returned. It is a string containing 'patch', 'line', 'point', or 'text'. The region of interest can be given as a point latitude and longitude or as a region with two-element vectors of latitude and longitude limits. The units of latitude and longitude are degrees. The data covering the requested region is returned, but will include data extending to the edges of the tiles. The result is returned as a Mapping Toolbox™ Version 1 display structure.

struct = vmap0data(devicename,library, ...) specifies the logical device name of the CD-ROM for computers that do not automatically name the mounted disk.

[struct1, struct2, ...] = vmap0data(...,{topolevel1,topolevel2,...}) reads several topology levels. The levels must be specified as a cell array with the entries 'patch', 'line', 'point', or 'text'. Entering {'all'} for the topology level argument is equivalent to {'patch', 'line', 'point', 'text'}. Upon output, the data structures are returned in the output arguments by topology level in the same order as they were requested.

Background

The Vector Map (VMAP) Level 0 database represents the third edition of the Digital Chart of the World. The second edition was a limited release item published in 1995. The product is dual named to show its lineage to the original DCW, published in 1992, while positioning the revised product within a broader emerging family of VMAP products. VMAP Level 0 is a comprehensive 1:1,000,000 scale vector base map of the world. It consists of cartographic, attribute, and textual data stored on compact disc read-only memory (CD-ROM). The primary source for the database is the Operational Navigation Chart (ONC) series of the U. S. National Geospatial Intelligence Agency (NGA), formerly the National Imagery and Mapping Agency (NIMA), and before that, the Defense Mapping Agency (DMA). This is the largest scale unclassified map series in existence that provides consistent, continuous global coverage of essential base map features. The database contains more than 1,900 MB of vector data and is organized into 10 thematic layers. The data includes major road and rail networks, major hydrologic drainage systems, major utility networks (cross-country pipelines and communication lines), all major airports, elevation contours (1000 foot (ft), with 500 ft and 250 ft supplemental contours), coastlines, international boundaries, and populated places. The database can be accessed directly from the four optical CD-ROMs that store the database or can be transferred to magnetic media.

Examples

The devicename is platform dependent. On an MS-DOS based operating system it would be something like 'd:', depending on the logical device code assigned to the CD-ROM drive. On a UNIX® operating system, the CD-ROM might be mounted as '\cdrom', '\CDROM', '\cdrom1', or something similar. Check your computer's documentation for the right devicename.

s = vmap0data(devicename,'NOAMER',41,-69,'?','patch');

??? Error using ==> vmap0data
Theme not present in library NOAMER

Valid theme identifiers are: 
libref : Library Reference
tileref: Tile Reference   
bnd    : Boundaries       
dq     : Data Quality     
elev   : Elevation        
hydro  : Hydrography      
ind    : Industry         
phys   : Physiography     
pop    : Population       
trans  : Transportation   
util   : Utilities        
veg    : Vegetation       

BNDpatch = vmap0data(devicename,'NOAMER',...
                     [41 44],[-72 -69],'bnd','patch')
BNDpatch = 
1x169 struct array with fields:
    type
    otherproperty
    altitude
    lat
    long
    tag

Here are other examples:

[TRtext,TRline] = vmap0data(devicename,'SASAUS',...
     [-48 -34],[164 180],'trans',{'text','line'});

[BNDpatch,BNDline,BNDpoint,BNDtext] = vmap0data(devicename,...
     'EURNASIA',-48 ,164,'bnd',{'all'});

More About

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Tips

Data are returned as Mapping Toolbox display structures, which you can then update to geographic data structures. For information about display structure format, see Version 1 Display Structures in the reference page for displaym. The updategeostruct function performs such conversions.

Latitudes and longitudes use WGS84 as a horizontal datum. Elevations and depths are in meters above mean sea level.

Some VMAP0 themes do not contain all topology levels. In those cases, empty matrices are returned.

Patches are broken at the tile boundaries. Setting the EdgeColor to 'none' and plotting the lines gives the map a normal appearance.

The major differences between VMAP0 and the DCW are the elimination of the gazette layer, addition of bathymetric data, and updated political boundaries.

Vector Map Level 0, created in the 1990s, is still probably the most detailed global database of vector map data available to the public. VMAP0 CD-ROMs are available from through the U.S. Geological Survey (USGS):

USGS Information Services (Map and Book Sales)
Box 25286
Denver Federal Center
Denver, CO 80225
Telephone: (303) 202-4700
Fax: (303) 202-4693

    Note   For details on locating map data for download over the Internet, see the following documentation at the MathWorks Web site: Finding Geospatial Data.

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