[aprssig] Re: APRSPoint and other map sources
Stephen H. Smith
WA8LMF2 at aol.com
Thu Dec 2 00:54:59 CST 2004
Matt Werner wrote on 12/1/2004, 8:32 PM:
> I have 2003 street
> level data for any part of the US, simply by downloading the map and
> placing it in the correct directory.
> I don't personally find the maps to be ugly either... It shows a line
> for a road - only so many ways to represent a road...
> Just one user's point of view anyway..
I fully agree with the original poster's comment about "uglyness" of
maps. The raw Tiger file database, as presented in most applications
that use it, fails to distinguish (by using different line weights
and/or colors) between dirt roads, minor side streets, major urban
streets, or secondary highways. About the only roads that look different
are the Interstate highways. Additionally, limited-access freeway-type
roads that happen to have local or state numbers (instead of federal I-
numbers) are often rendered looking like local streets instead.
Furthermore, for mobile non-Internet-connected operation, the entire raw
Tiger database, as downloaded, is enormously bulky compared to the
commercially-enhanced databases that come with Delorme Street Atlas,
MapPoint, Streets&Trips, Precision Mapping, etc. These programs encode
every street and road segment in the US, including street-address
indexing, into a total database of less than 1 GB.
For mobile applications, don't even mention the various bitmap
image-oriented formats such as Terraserver images, USGS Topo map images,
GeoTIFFs, etc. Just too incredibly bulky for large areas compared to
compressed vector formats.
By the way, both MapPoint 2004 (used by APRSpoint and UI-View's add-in
UI-Point) and Precision Mapping 6.0 (used directly by UI-View) use
the SAME commercially enhanced and cleaned-up Tiger database sold by GDT
(Geographic Data Technology) to various map publishers.
You will see almost exactly the same errors, missing streets, etc
(as well as accurate rendition of freeway exit and transition ramps,
interior roads in major airports and industrial parks, etc) in both
products because they are based on the same data source. Only the
presentation (line weights, colors, etc.) are different.
The points of interest (parks, museums, airports, schools, etc.)
called out in the two products WILL be different since this information
is purchased from completely different sources and is overlaid on the
Stephen H. Smith wa8lmf (at) aol.com
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