Digital Nautical Chart (DNC) - NGA

MIL-PRF-89023
15' x 15' TILE MKNQ4545
0045 1545 3045
0030
1530
0015 1515
3030
3015
0000 1500 3000
GEOREF 1° x 1° OFFSET = MKNQ
8
4545
4530
4515
4500
1° x 1°
FIGURE 4. 15' by 15' tiling scheme example from the
GEOREF offset "MKNQ".
3.5.7 Vector Product Format (VPF). The DNC is implemented in Vector
Product Format and conforms to MIL-STD-2407 for its data structure.
3.5.8 Distribution medium. The DNC shall be distributed on CD-ROM
discs, each of which is a single VPF database. The format of the CD-ROM discs
conforms to ISO Standard 9660.
3.5.9 Geographic organization. The DNC shall be organized on multiple
CD-ROM discs based on geographic regions of the world. There is no overlap
present on adjoining discs.
3.5.10 GIS analysis. The DNC is topologically structured and may
support GIS analysis; however, in order to perform GIS functions, the DNC must
be used with a GIS software system. The kind of GIS functions possible
depends upon the specific GIS program used to access the database. The DNC is
not a GIS. However, the DNC database can be a component of a GIS when
combined with separate GIS software.
3.5.11 Minimum hardware specification. The DNC may be accessed by any
hardware system that includes a CD-ROM reader and supports the ISO 9660
interface.
3.5.12 Operating system. The DNC directories utilize the standard DOS
system disc directory structure and file-naming conventions. All file
structures of the DNC are contained in DOS directories. The coverages within
the library are contained in DOS subdirectories. The DNC may also be accessed
by other operating systems.
3.5.13 Database size. The size of a DNC database is dependent on the
complexity of the hardcopy source used to produce the product and the number
of particular charts included in the database. A single database will not
exist on more than one CD-ROM.