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Read selected data from the Vector Map Level 0
Syntax
struct1 = vmap0data(library,latlim,lonlim,theme,topolevel) struct1 = vmap0data(devicename,library,...) [struct1,struct2,...] = vmap0data(...,{topolevel1,topolevel2,...})
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 basemap 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 National Imagery and Mapping Agency's (NIMA) Operational Navigation Chart (ONC) series. This is the largest scale unclassified map series in existence that provides consistent, continuous global coverage of essential basemap features. The database contains more than 1,900 megabytes 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 500ft and 250ft 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 a magnetic media. (From the NIMA Metadata referenced below).
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 geographic data 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.
Remarks
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 will give 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.
The VMAP0 is available from the following sources:
Information on the VMAP0 data can be found at <http://mapping.usgs.gov/esic/cdrom/cdlist.html>.
Examples
The devicename is platform dependent. On a 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
[TRtext,TRline] = vmap0data(devicename,'SASAUS',... [-48 -34],[164 180],'trans',{'text','line'}); [BNDpatch,BNDline,BNDpoint,BNDtext] = vmap0data(devicename,... 'EURNASIA',-48 ,164,'bnd',{'all'});
See Also
vmap0read |
Read a VMAP0 file |
vmap0rhead |
Read a VMAP0 file header |
displaym |
Project data contained in a map structure |
extractm |
Extract vector data from a map structure |
mlayers |
GUI for manipulating map layers |
| | usgsdems | vmap0read | |