VMAP (see
VMAP format) is a comprehensive vector base map of the
world. It consists of cartographic, attribute, and textual data, usually
stored on CD-ROM in a specified file and folder structure. The data
is tiled and spatially indexed for rapid access. The precision levels
for VMAP data for
JViews Maps for Defense are: level 0 (1:1,000,000 scale),
level 1 (1:250,000 scale), and level 2 (1:100,000 and 1:50,000 scale).
VMAP data is in geographic projection and coordinates are expressed
in degrees.
There are two ways of reading VMAP data:
Use an
IlvVMAPReader instance directly. In this case, you must write
all of the code required to render the VMAP map features into graphic
objects, and to add them to the manager.
Use an
IlvVMAPDataSource. This is a convenient way of performing all of the
above operations at once and is more integrated with the data model
of the map.