nswvic.txt

    The file nswvic.zip contains dosAPRS maps derived from winAPRS
maps made by Mark Sproul from the Digital Chart of the World (DCW).
The DCW is a four CD set of maps made from USA miltary Air Navigation
Charts. The scale of the DCW is 1:1,000,000.  The winAPRS maps contain
roads, streams, railroads, political and ocean boundaries, populated
place outlines and 1000ft contour lines. The populated place and contour
lines were not converted for the dos maps. Dos maps are digital line
graphs and are limited to 3000 points. Mac/winAPRS does not have
this map size limitation and can have more features.

    The file nswvic.zip contains dos APRS maps for the Australian
states of New South Wales and Victoria.  The area covered is roughly
from 30S to 39S and from 140E to 154E.  This region is covered by
104 dos maps that are each 50nm N-S and 67nm E-W.

IMPORTANT NOTE:
    Not all these files are APRS ready!  Those that are less than
3000 points will work as is. These maps are usually 30K or less in
size. See *.log file info below. Change the extention of these files
from *.dmf to *.map.  The remaining big maps need to be edited for use
with dosAPRS.  The program mapfix32.exe, which is distributed with
dosAPRS, will enable the map maker to join line segments, kill unwanted
features, delete points within a line feature or split a map into
two smaller maps.  Complete instructions for using mapfix are in the
APRS readme files.  Files with extension *.log are text files generated
during map conversion.  These log files list the area covered by each
map and the approximate size of each map in points.  Any map listed in
a log file but not found in the zip file was deleted by me either
because it was blank ocean area or contained only minor islands that
I considered unimportant.

HINTS to Australian map makers
    All roads are one color because the road attributes that classify
roads as primary, secondary, major or minor are not carried over from
the DCW in the Sproul's maps.  Likewise, lakes and streams are all
the same including the many dry lake beds and intermittent streams.
You know your country best and can decide what features are important
for Australian APRS.  Deleting unimportant features will help shrink
large maps to dosAPRS size.  I was struck by the number of remarkably
straight roads in Australia.  You can compress maps by making sure
that these are only two point straight lines.  The digitization
process may have inserted a point every few cm.


Jack Cavanagh, KB4XF
Falmouth, Virginia, USA
Dec 1997
cjcav@earthlink.net