Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Re: fire & police department navigation
    From: Brooke Clarke
    Date: 2004 Jul 20, 14:25 -0700

    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

    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
    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
    "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
    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.

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site