Subject: PNT file format
From: Paul B. Anderson (804) 853-7595 E-mail: pbander@infi.net

  The PNT format was devised by Fred Popeschil and Antonio Rivera for their
public domain Micro World Data Bank II (MWDBII) data base.  The PNT file is
a binary file where each full record consists of 3 short integer values. 

				Possible
  1st short Integer value:	Header Values	Feature
				-------------	-------
				1		Data Level 
				2		Data Level
				3		Data Level
				4		Data Level
				5		Data Level
				1000 -> 1999	coastlines
				2000 -> 2999	country
				4000 -> 4999	internal political borders
  				5000 -> 5999	island
				6000 -> 6999	lake
				7000 -> 7999	river
 
   2nd short Integer value:   Latitude in signed minutes (+/- 5400)

   3rd short Integer value:   Longitude in signed minutes (+/- 10800)

POLYLINES:
Latitude and longitude data in PNT files are arranged into polylines (or
spaghetti). As an example (from MWDB-POLY), France is one polyline. All the
lat/lon data points that make up France's coastlines and political borders
are in one continuous line. 

HEADER:
The start of a new polyline is Indicated by a header value that is greater
than 5. The list above, indicates all the possible polyline starting values.

DATA LEVEL:
The data level (1 -> 5) determines the amount of detail in your map.  When
writing programs using this data, level 1 is full detail and level 5 is the
least amount of detail.

Level 1 -> plot all data points => 1
Level 2 -> plot all data points => 2
Level 3 -> plot all data points => 3
Level 4 -> plot all data points => 4
Level 5 -> plot all data points = 5

The start of each new polyline is understood to be at level 5.  The end
of each polyline will be at level 5.

NOTEs: 

Because the Short Integer is used, all latitude and longitude values
are ROUNDED TO THE NEAREST MINUTE. This limits the usefulness of this
data to small scale maps only.

Multiply the 2nd or 3rd short integer values by 2.908882086657222D-04
to go from signed minutes straight to Radians.
 
Divide the 2nd or 3rd short integer values by 60 to go from signed minutes
straight to Decimal Degrees.
 
