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Assessment of Advanced GIS Tools for E-911 Services. Cole Kelleher Benjamin Post CSCI 5980. Outline. Motivation Goals Assumptions Existing GIS Applications Dijkstra’s Algorithm Fortune’s Algorithm Solution Validity of Goals Issues and Limitations. Motivation.
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Assessment of Advanced GISTools for E-911 Services Cole Kelleher Benjamin Post CSCI 5980
Outline • Motivation • Goals • Assumptions • Existing GIS Applications • Dijkstra’s Algorithm • Fortune’s Algorithm • Solution • Validity of Goals • Issues and Limitations
Motivation • Proliferation of location aware devices • Increase in GIS analysis • Large potential for application of new GIS services and workflows for emergency responders • Improved response time • Efficient resource management • Post emergency response analysis
Goals • Identify potential value added GIS functionality for emergency response • Identify infrastructure to support this functionality • Verify validity of GIS functionality • Does it already exist? • Would it be useful?
Assumptions • Emergency calls collected via automated and manual methods • Call vs. triggered alarm • Formal emergency types for multi-entity (Fire Dept., Police Dept., etc.) use. • Use of location aware devices by emergency response personnel • Smart-phones, GPS enabled laptops and receivers
Existing GIS Applications • Crime Stat • Post crime analysis tool • Automatic Vehicle Location (AVL) • Tracks emergency vehicles • CAD / GIS • ESRI, AutoCAD • Display EMR locations • Display critical infrastructure
Overview • Well known search algorithm within CSci • Finds the shortest path between two points • Can be run on a variety of inputs • Graphs – both pure and weighted • Rasters • Speed dependent upon heap • O(V²) to O(E + V log V)
Dijkstra’s Modification • Graphs are weighted by Time • Road Network: road speed/distance = time • Algorithm is modified to allow the search to run until a specified time value has been reached along each path. • Once the search has reached its maxima of allowed travel time across all nodes, we receive that heap of all nodes which meet the time constraint • Useful for determining time based suspect search perimeter and/or optimal route
Overview • Maintain Voronoi polygons for emergency personnel to query for optimal response • Functional for nearest entity/response team determination • Three separate sets of polygons • Fire and EMTs, which are static • Police, which would are dynamic • Operates in O(n log n) time • n = number of entities
Algorithm • Assumes point set is sorted • Runs a sweep line across the set • Once a point is reached, calculates a parabola which forms the trailing beach line • At the intersection of 3 beach lines, creates a vertex for one of the set’s polygons
Interview with Wayne Betcher • Dispatcher, Goodhue County Sheriff • Committee, Sheriff’s Assoc NG9-1-1 • Future Technology • 911 via text, VoIP • Send/Receive video • Social Media • Use of collected data • Spatio-Temporal analysis of patrol routes
Validity of Goals • Use of state-of-the-art technologies to support efficient emergency response • Increased response time and delivery of spatial data relevent to the emergency • Able to meet the needs of multiple emergency entities • Recording of spatial location data for post emergency response assessment and improvement • Compatible with future crime reporting methods (text messages, social media, etc.)
Issues and Limitations • Difficult to Implement and test • Real-world testing, infrastructure, input specifications, and delivery method will need to be addressed • Modified Dijkstra’s Algorithm • Unknown at this time, would likely be more useful once NG911 services are enabled • Cordons: Manhunts and Amber Alerts • Fortune’s Algorithm • Difficult to assess, nature of patrol officer might prohibit closest officer from responding • Expressed need for polygons representing E911 areas, Fortune’s might not be appropriate
Sources • Dijkstra’s Algorithm • http://en.wikipedia.org/wiki/Dijkstra's_algorithm • Fortune’s Algorithm • http://en.wikipedia.org/wiki/Fortune%27s_algorithm • Automatic Vehicle Location • http://en.wikipedia.org/wiki/Automatic_vehicle_location • Next Generation 911 • http://en.wikipedia.org/wiki/Next_generation_911