Next message: Jared Sherman: "Re: fire & police department navigation"
Hi:
In the Santa Clara county area of California the street numbers are 5
digits with the first 3 indicating the distance from a N-S meridian
through the center of the county (middle of San Jose), so emergency
responders for county addresses know right away about where in an E-W
direction they are going. This gives them a big picture right away and
allows crews to roll in the correct direction without any further details.
In San Francisco the street names are alphabetical on the first letter
of the name to make it easier for emergency crews to find a street.
Have Fun,
Brooke Clarke, N6GCE
--
http://www.PRC68.com
http://www.pacificsites.com/~brooke/PRC68COM.shtml
Paul Hirose wrote:
>George Huxtable wrote:
>
>
>>The trouble with many road atlases is in their gridding. In many cases, the
>>grid markings relate only to each map-page and are unrelated to the
>>gridding of adjacent map-pages and bear no relation to a national
>>coordinate system or to latitude or longitude or WGS84. So there's no way
>>to relate them to coordinates taken from a GPS receiver.
>>
>>
>
>Based on what I've heard on my scanner, the Los Angeles County Fire
>Department "coordinate system" consists of the map page and grid
>square from the Thomas Brothers road atlas! On the other hand, Kern
>County Fire uses the township and section number from the U.S. public
>land survey system. Neither system is usable with common GPS
>receivers.
>
>Recently I heard an LA fire engine respond on an assistance call into
>Kern County. They had difficulty locating the assignment, and said
>that in the future they would need a Thomas Brothers map reference
>from the dispatcher.
>
>Having totally incompatible georeferencing systems in two adjacent
>counties is common in the United States. According to a 2002
>government report:
>
>"Table 44 and 45 (pp. 89-90) collectively address the ability of fire
>departments to access a map coordinate system with sufficient
>standardization of format to provide effective functionality in
>directing the movements of emergency response partners.
>
>"Table 44 indicates that nearly half of all fire departments have no
>map coordinate system. This is a problem particularly for smaller
>communities, up to 99,999 population. About one-seventh of all
>communities with at least 500,000 population have no map coordinate
>system.
>
>"Table 45 indicates that the vast majority of departments with a map
>coordinate system have only a local system, which means the system
>they have is unlikely to be usable with global positioning systems
>(GPS) or familiar to, or easily used by, non-local emergency response
>partners, such as Urban Search and Rescue, the National Guard, and
>state or national response forces. Moreover, interoperability of
>spatial-based information systems, equipment, and procedures will
>likely be rendered impossible beyond the local community under these
>circumstances. This reliance almost exclusively on local systems
>exists across-the-board, in all sizes of communities."
>
>
>I suspect the use of a coordinate system is more common in the big
>counties of the West. It would be hard to function without one, due to
>the great areas involved. For example, Kern County is 8070 square
>miles, bigger than the state of New Jersey. Two other counties in
>California are even bigger.
>
>As far as I can tell from the radio traffic, LA and Kern county fire
>and sheriff units navigate the old fashioned way, with paper maps and
>pilotage. Dispatchers announce the location's street address and
>bracketing cross streets. Sometimes it's an obscure place and
>responding units have to discuss the route on the radio, or get talked
>in by the dispatcher.
>
>GPS is obviously available on fire engines, because they're able to
>provide lat/lon when they need a helicopter to land. In fact, "GPS" is
>sometimes synonymous with lat/lon coordinates. A fireman might say on
>the radio, "I have GPS for the medevac copter, when you're ready to
>copy."
>
>However, the fire and sheriff departments I monitor don't seem to use
>electronics for navigation. And any system whereby the dispatcher
>could load coordinates directly into a vehicle's GPS receiver is pure
>science fiction, at least in my area.
>
>
>
>
