The Nautical Chart Numbering System, Continued
Number of Digits
5 (11000-99999) Larger than
In this category are all standard
nautical charts at a scale larger
than 1:2,000,000. At scales such
as this, the charts cover portions
of the coastline rather than
significant portions of ocean
This category consists of combat
charts and combat training charts.
A random numbering system is
used to prevent the identification
of the geographical area covered
by a classified combat chart
without referring to the catalog.
One reason for this is to allow you
to order classified combat charts
with an unclassified requisition.
The five-digit category contains all the large-scale and medium-scale
charts of the world. These are the primary nautical charts. The
five-digit charts are based on the nine regions of the world, as shown in
figure 1-15. The first of the five digits indicates the region in which the
chart is depicted. The first and second digits together indicate the
geographic subregion within the region, and the last three digits identify
the geographic order of the chart within the subregion.