[aprssig] Winaprs and Precision Mapping
kc2mmi at verizon.net
Thu Apr 20 12:19:46 CDT 2006
I haven't spoken to the USCensus folks since last year so my impression could
easily be outdated or simply wrong. But at that time they were begging for
funding and updating some 100 counties per year with no indication of larger
funding in sight. Is this improvement funding something that was just recently
granted to them? Is there a schedule for completion now?
They also emphasized "Not for navigation" and did not indicate any professional
cartographers were using them as a source. In fact, they said flat out that for
some new roads, someone would just drive and enter the distance based on the car
Rather, the USGS maps and the state platte/road maps maintained by each state
appear to be the authoritatave sources. One firm actually told me they use state
mapping sources several years ago, and that (at that time) they didn't publish
for several states because the source data was too expensive for them to
purchase. (Which is not to say USGS maps are always perfect or up to date, much
as they try.<G>)
I don't know that this is the current situation.
I certainly will agree that I've seen too many "computer navigation" sources,
including the ones creditted in the Google maps, making what appear to be the
same errors that TIGER maps have in some cases already corrected.
I'd be very curious to know which map makers actually will admit they are using
official "not for navigation" maps as their sources. Mappers today just don't
seem to be the academic professionals that cartographers once were. And
end-users, certainly, seem to get no warning about the products they are using.
Which is to me the real issue here: GPS and TIGER need some caveats applied. At
sea, a 1/10th mile error may be meaningless. In a city, it can be a killer.
"Also, note that ALL of the major map makers start out with TIGER
data, then they add to it and enhance it. The census bureau is in the
middle of a 300 million dollar improvement project."
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