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Geographical Information Systems (GIS) for Public Safety Applications NC EMToday 2000


Title: GIS for EMS and Fire Author: William E. Ott Last modified by: William E. Ott Created Date: 9/11/2000 4:25:34 PM Category: NCEMS Document presentation format – PowerPoint PPT presentation

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Title: Geographical Information Systems (GIS) for Public Safety Applications NC EMToday 2000

Geographical Information Systems (GIS)for Public
Safety ApplicationsNC EMToday 2000
  • Pressley Lorbacher
  • William E. Ott
  • Scott Roberts
  • Mike Smith
  • Joseph Zalkin

What is GIS?
  • Geographic Information Systems
  • In the strictest sense, a GIS is a computer
    system capable of assembling, storing,
    manipulating, and displaying geographically
    referenced information , i.e. data identified
    according to their locations. Practitioners also
    regard the total GIS as including operating
    personnel and the data that go into the system.

How does GIS work?
  • A GIS, which can use information from many
    different sources, in many different forms can
    help with such analyses. The primary requirement
    for the source data is that the locations for the
    variables are known.
  • Location may be annotated by x,y, and z
    coordinates of longitude, latitude, and
    elevation, or by such systems as ZIP codes or
    highway mile markers. Any variable that can be
    located spatially can be fed into a GIS.
  • Several computer data bases that can be directly
    entered into a GIS are being produced by Federal
    agencies and private firms. Different kinds of
    data in map form can be entered into a GIS.

How does GIS work?
  • A GIS can also convert existing digital
    information, which may not yet be in map form,
    into forms it can recognize and use. For example,
    digital satellite images can be analyzed to
    produce a map like layer of digital information
    about vegetative covers.
  • Likewise, census or hydrologic tabular data can
    be converted to map-like form, serving as layers
    of thematic information in a GIS.

GIS Buzzwords
  • Shape Files
  • Layers
  • Geocoding
  • Networking

Data Capture How can a GIS use the information
in a map?
  • If the data to be used are not already in digital
    form, that is, in a form the computer can
    recognize, various techniques can capture the
  • Maps can be digitized, or hand-traced with at
    computer mouse, to collect the coordinates of
  • Electronic scanning devices will also convert map
    lines and points to digits.
  • Global Positioning System (GPS) surveying and
    input from stationary receivers or mobile AVL
  • Data capture - putting the information into the
    system - is the time-consuming component of GIS
    work. Identities of the objects on the map must
    be specified, as well as their spatial

Data Systems
  • GIS data can be accumulated in a variety of ways,
  • GPS (most accurate method of exact incident
  • AVL - GPS
  • Manual address keying into a data system which is
    then geocoded to the GIS system

Projection and Registration
  • A property ownership map might be at a different
    scale from a soils map. Map information in a GIS
    must be manipulated so that it registers, or
    fits, with information gathered from other maps.
    Before the digital data can be analyzed, they may
    have to undergo other manipulations - projection
    conversions, for example - that integrate them
    into a GIS.
  • Projection is a fundamental component of
    mapmaking. A projection is a mathematical means
    of transferring information from the Earth's
    three-dimensional curved surface to a
    two-dimensional medium - paper or a computer
    screen. Different projections are used for
    different types of maps because each projection
    is particularly appropriate to certain uses. For
    example, a projection that accurately represents
    the shapes of the continents will distort their
    relative sizes.

Projection Example
Data Modeling
  • It is difficult to relate flood plain maps to
    rainfall amounts recorded at different points
    such as airports, television stations, and high
  • GIS, however, can be used to depict two- and
    three-dimensional characteristics of the Earth's
    surface, subsurface, and atmosphere from
    information points.

Info Retrieval, Modeling, and Networking
  • What do you know about the swampy area at the end
    of your street? With a GIS you can "point" at a
    location, object, or area on the screen and
    retrieve recorded information about it from
    off-screen files.
  • Using scanned aerial photographs as a visual
    guide, you can ask a GIS about the geology or
    hydrology of the area or even about how close a
    swamp is to end of a street. This kind of
    analytic function allows you to draw conclusions
    about the swamp's environmental sensitivity.
  • In the past 35 years, were there any gas stations
    or factories operating next to the swamp? Any
    within two miles and uphill from the swamp? A GIS
    can recognize and analyze the spatial
    relationships among mapped phenomena. Conditions
    of adjacency (what is next to what), containment
    (what is enclosed by what), and proximity (how
    close something is to something else ) can be
    determined with a GIS.

Info Retrieval, Modeling, and Networking
  • If all the factories near a wetland were
    accidentally to release chemicals into the river
    at the same time, how long would it take for a
    damaging amount of pollutant to enter the wetland
  • A GIS can simulate the route of materials along a
    linear network. It is possible to assign values
    such as direction and speed to the digital stream
    and "move" the contaminants through the stream
  • This same networking process can be applied to
    public safety response data, thus allowing best
    route type planning to be done for given areas,
    units, times of day, days of week, or any
    combination of these

Data Output Information
  • A critical component of a GIS is its ability to
    produce graphics on the screen or on paper that
    convey the results of analysis to the people who
    make decisions about resources.
  • Wall maps, mapbooks, and other graphics can be
    generated, allowing the viewer to visualize and
    thereby understand the results of analyses or
    simulations of potential events.

Application of GIS
  • Mapmaking (cartography)
  • Site Selection (stations, command posts, etc..)
  • Emergency Response Planning
  • Simulation of environmental effects or impact of
    events (chemical spill, spraying, flooding, etc..)

Coordinate Systems
  • There are many basic coordinate systems familiar
    to students of geometry and trigonometry.
  • These systems can represent points in
    two-dimensional or three-dimensional space.
  • René Descartes (1596-1650) introduced systems of
    coordinates based on orthogonal (right angle)
  • These two and three-dimensional systems used in
    analytic geometry are often referred to as
    Cartesian systems.
  • Similar systems based on angles from baselines
    are often referred to as polar systems.

Coordinate Systems
  • The most commonly used coordinate system today is
    the latitude, longitude, and height system.
  • The Prime Meridian and the Equator are the
    reference planes used to define latitude and
  • The geodetic latitude (there are many other
    defined latitudes) of a point is the angle from
    the equatorial plane to the vertical direction of
    a line normal to the reference ellipsoid.
  • The geodetic longitude of a point is the angle
    between a reference plane and a plane passing
    through the point, both planes being
    perpendicular to the equatorial plane.
  • The geodetic height at a point is the distance
    from the reference ellipsoid to the point in a
    direction normal to the ellipsoid.

Coordinate SystemsUniversal Transverse Mercator
  • Universal Transverse Mercator (UTM) coordinates
    define two dimensional, horizontal, positions.
  • UTM zone numbers designate 6 degree longitudinal
    strips extending from 80 degrees South latitude
    to 84 degrees North latitude.
  • UTM zone characters designate 8 degree zones
    extending north and south from the equator.
  • There are special UTM zones between 0 degrees and
    36 degrees longitude above 72 degrees latitude
    and a special zone 32 between 56 degrees and 64
    degrees north latitude.
  • Each zone has a central meridian. Zone 14, for
    example, has a central meridian of 99 degrees
    west longitude. The zone extends from 96 to 102
    degrees west longitude.
  • Eastings are measured from the central meridian
    (with a 500km false easting to insure positive
  • Northings are measured from the equator (with a
    10,000km false northing for positions south of
    the equator).

Geodetic Datums
  • Referencing geodetic coordinates to the wrong
    datum can result in position errors of hundreds
    of meters. Different nations and agencies use
    different datums as the basis for coordinate
    systems used to identify positions in geographic
    information systems, precise positioning systems,
    and navigation systems. The diversity of datums
    in use today and the technological advancements
    that have made possible global positioning
    measurements with sub-meter accuracies requires
    careful datum selection and careful conversion
    between coordinates in different datums.

Earth Surfaces
GIS Software
  • ESRI ArcInfo / ArcView plus many add in modules
  • ESRI is the market leader and gold standard
    within the government and engineering communities
  • Other vendors offer competing products, which
    combined make up less than 15 of the GIS market

GIS Software Costs
  • 8,000 and up for full GIS system
  • 1,000 and up for GIS modeling only. This is
    what the typical public safety agency would need
    if their local government has a GIS system that
    can feed map data to analyze with response data

GIS Hardware Costs
  • Full blown GIS will need a server, Oracle, SQL
    Server, DB2, etc.. as a repository. This easily
    can be 15,000 to 20,000.
  • GIS and GIS modeling will need workstations,
    faster is better, LARGE screen monitors. This
    would run in the 1,500 to 4,000 range.
  • Color printers / plotters for maps. Pricing from
    200 up to tens of thousands of dollars.

Public Safety Specifics for GIS
  • Plotting and analyzing call patterns
  • Plotting and analyzing best response patterns (no
    more pins in maps)
  • Determining positioning for units
  • Modeling of hazard areas..ties to a reverse 911
    system to allow for automated evacuation
    notification in emergencies, etc..

Data Drives Decisions
  • Garbage In - Garbage Out
  • A Thing Seldom Looked for is Seldom Found
  • New Locations
  • Historical Data
  • Pre-Planning

Public Perception
  • Response Time Saves Lives
  • Where
  • When
  • How Long
  • Multi-unit Response Configurations

  • Special Services Locations
  • Dialysis
  • Womans Clinics
  • Free Standing Care Facilities (Cath Labs)

Durham North Carolina
  • County covers 299 Square Miles
  • City covers 95 Square Miles
  • Total County Population 235,000
  • Total City Population - 178,000

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EMS Responses by Unit1999
  • City Units
  • Medic 1 - 3,067
  • Medic 2 - 2,530
  • Medic 3 - 3,755
  • Medic 5 - 4,057
  • Medic 6 - 3,759
  • Medic 8 - 2,332
  • County Units
  • Medic 30 - 198
  • Medic 40 - 675
  • Medic 50 - 504
  • Medic 60 1,305
  • Medic 70 592

Calls by Area
  • City North - 9,217
  • City South - 12,133
  • County North - 1,247
  • County South - 1,173

GIS Mapping
  • TB Cases 1999 (19)
  • Stabbings - Year to Date 2000 (60)
  • Gunshots - Year to Date 2000 (130)
  • Homicides - Year to Date 2000 (25)

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Geographical Information Systems
  • Using GIS to Plan and Make Changes in the way EMS
    Serves Their Local Community
  • Durham County EMS System
  • An Actual Project

Real Life GIS
  • Defining Change

  • How Does the Public Evaluate the EMS System?
  • How Do Public Officials Evaluate the EMS System?

  • As an EMS Administrator How Do You Evaluate Your

  • Response Times!
  • Response Times!
  • Response Times!

Measuring Data for Use in Geographical
Information Systems
  • Data Has to Be Consistent.
  • Data Has to Be Accurate.
  • You Have to Know What You Want to Measure.

  • Garbage In Garbage Out

Defining Change
  • What Problems Did We Face in Our System?
  • Why?
  • What Should We Do to Fix These Problems?

Durham County EMS
  • 27,000 Annual Call Volume
  • 6 Paramedic Units in the City
  • 6 Paramedic Units in the County Fire Stations
    From 7 A.M. To 7 P.M.
  • City Fire Operates 21 First Responder Units From
    12 Stations

  • Measured All Emergency Responses Where Patient
    Contact Was Encountered in a Three Month Period
    of Time. (5123)
  • Recorded Response Times in Excess of 8 Minutes
    From Dispatch to Arrival in the Same Given Period
    of Time. (109)

  • What Does This Data Tell You As an Administrator?

  • A Picture Is Worth a Thousand Words
  • or Approximately
  • 600,000 !

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  • Now As Administrators What Does
  • This Picture Tell You?

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What did the picture identify?
  • Definite Need for Southwest Paramedic Coverage.
  • Inner City Call Volume Was Greater Than the
    Number of Available Paramedic Units.
  • Calls in the County That Were in Excess of 8
    Minute Response Times Were at Night When the
    Paramedic Coverage Was Discontinued.

What did we do ?
  • Placed a Paramedic Unit in the Southwest Portion
    of Durham Utilizing a City Fire Station.
  • Expanded Paramedic Coverage in the County Fire
    Stations to 24 Hours.

  • Implemented Three (3) City Fire Department
    EMT-Intermediate Transport Units in the Inner
    City Districts to Back-up the Inner City
    Paramedic Units When They Are Occupied.
  • County EMS Contracted With Parkwood EMS to
    Provide Paramedic Service in the South /
    Southwest Area of Durham With 2 Paramedic Units.

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Questions CommentsPlease see the GIS mapping
displays around the room
Thank You!