[aprssig] strange map behavior

[WA8LMF@aol.com]

Art Snapper wrote on 8/28/2004, 8:22 PM:

 > I have been playing around with aprs on my sail oat (nk8x-8) on Lake
 > Michigan. The maps on findu.com and aprsworld.net behave strangely for
 > plots on the lake. I captured a plot and saved it here:
 > http://lakemichiganfun.com/plot.png
 > Perhaps this is an old problem. I subscribe to the APRS sig in a
 > digest and must confess to not reading all the posts!
 >
 >

The aprsworld maps that are used by findu are composed (like most GIS 
and map display systems) of multiple layers of data displayed one on top 
of the other.  Highways, city streets, state and county boundries, etc 
may come from different sources with wildly differing levels of 
completeness and accuracy.

There appear to be numerous errors and omissions in the database 
aprsworld uses to place bodies of water (ocean coastline, lakes, rivers 
and streams, etc) on the maps.  I have noticed here on the west coast 
that many portions of the Pacific Coast Highway are "under water" also 
while several major lakes and reservoirs don't show at all!