[aprssig] Re: FindU Maps Quirky
Stephen H. Smith
WA8LMF2 at aol.com
Mon Feb 7 02:53:02 CST 2005
Ray McKnight wrote on 2/6/2005, 11:21 PM:
> Steve, if you zoom in to street level on my FindU map,
> You’ll notice that although I am actually located about 1 mile
> From the water, a significant amount of the streets in my neighborhood
> Are depicted as being in Puget Sound, yeah, in the water!
> Gee, looking at Seattle a little closer now, there seems to be
> thousands of streets
> Depicted as being in the drink. Any hope of correcting this??
> Does this link show what I’m talking about:
This has nothing to do with findu!
Street information, outlines of cities, counties, states, and of bodies
of water are typically stored in separate databases and then drawn as
multiple layers on top of each other. The map you see is assembled
on-the-fly from multple databases at aprsworld.com at findu's request.
In turn, the various layers of data come from different public-domain
sources and have varying degrees of accuracy, especially when data
referenced to one datum is converted to another.
The water features database which contains coastlines, lakes and rivers
seems to have major errors in it. I see the same problems here in
Southern California where most of Santa Monica, LAX and parts of the San
Diego Freeway (I-405) are "underwater". [And, please, no smart cracks
about them really being that way after the recent January floods!]
The real issue is how much do you want to <<PAY>> to have access to
commercially enhanced and corrected data versus using free public domain
Note: You can see some similar errors in Precision Mapping 7.0 Zoom
in on the channel between the eastern tip of Michigan's Upper Peninsula
and Sault Ste Marie, Ontario. You will see Canadian roads, including
Ontario Route 548 apparently in the water, along with a bunch of small
towns. Somehow the outline of an entire island (St Joseph's) slipped
through the cracks of the Canadian database provided to Undertow
software by GDT (Geographic Data Technology).
Stephen H. Smith wa8lmf (at) aol.com
Home Page: http://wa8lmf.com
New/Updated Symbols for http://members.aol.com/wa8lmf/ham
UI-View and APRSplus:
More information about the aprssig