UI for selecting data from Vector Map Level 0
vmap0ui(dirname) launches a graphical user
interface for interactively selecting and importing data from a Vector
Map Level 0 (VMAP0) data base.
dirname is a character
vector that specifies the folder containing the data base. For more
vmap0ui, click the Help button
after the interface appears.
devicename uses the logical device (volume) name specified
in the character vector
devicename to locate CD-ROM
drive containing the VMAP0 CD-ROM. Under the Windows® operating
system it could be
or some other letter. Under Macintosh OS X it should be
Under other UNIX® systems it could be
vmap0ui can be used on Windows without
any arguments. In this case it attempts to automatically detect a
drive containing a VMAP0 CD-ROM. If
to locate the CD-ROM device, then specify it explicitly.
vmap0ui screen lets you read data from
the Vector Map Level 0 (VMAP0). The VMAP0 is the most detailed world
map database available to the public.
You use the list to select the type of data and the map to select the region of interest. When you click the Get button, data is extracted and displayed on the map. Use the Save button to save the data in a MAT-file or to the base workspace for later display. The Close button closes the window.
The Map controls the geographic
extent of the data to be extracted.
data for areas currently visible on the map. Use the mouse to zoom
in or out to the area of interest. Type
help zoom for
more on zooming.
The VMAP0 divides the world into tiles of about 5–by–5 degrees. When extracting, data is returned for all visible tiles, including those parts of the tile that are outside the current view. The map shows the VMAP0 tiles in light yellow with light gray edges. The data density is high, so extracting data for a large number of tiles can take much time and memory. A count of the number of visible tiles is above the map.
The List controls the type
of data to be extracted. The tree structure of the list reflects the
structure of the VMAP0 database. Upon starting
the list shows the major categories of VMAP data, called themes. Themes
are subdivided into features, which consist of data of common graphic
types (patch, line, point, or text) or cultural types (airport, roads,
railroads). Double-click a theme to see the associated features. Features
can have properties and values, for example, a railroad tracks property,
with values single or multiple. Double-click a feature to see the
associated properties and values. Double-clicking an open theme or
feature closes it. When a theme is selected,
all the associated features. When a feature is selected,
all of that feature's data. When properties and values are selected,
the data for any of the properties and values that match (that is,
the union operation).
The Get button reads the currently selected VMAP0 data and displays it on the map. Use the Cancel button on the progress bar to interrupt the process. For a quicker response, press the standard interrupt key combination for your platform.
The Clear button removes any previously read data from the map.
The Save button saves the currently displayed VMAP0 data to a MAT-file or the base workspace. If you choose to save to a file, you are prompted for a filename and location. If you choose to save to the base workspace, you are notified of the variable names that will be overwritten.
Data are returned as Mapping Toolbox™ display structures
with variable names based on theme and feature names. You can update
vector display structures to geographic data structures. For information
about display structure format, see Version 1 Display Structures in the reference page
updategeostruct function performs such conversions.
redisplay the data from a file on a map axes. You can also use the
to read and display the data from a file. To display the data in the
base workspace, use
displaym. To display all the
display structures, use
To display all of the display structures using the
The Close button closes the
automatically detect a CD-ROM on Microsoft® Windows:
vmap0ui on Macintosh OS X (need
to specify volume name):