PROJECT DESIGN 

SPATIAL PROBLEM

To constuct optimal response routes from local firestations and hospitals to Alexander Humbolt School (Upper Manhattan) and Hernando Desoto School (Lower Manhattan).  Based on time of day, see which firestations and hospitals fall into up to 5 min, 10 min, 15min, 20min, 25min, and over 25 min response time intervals.  In the event of an emergency, this would help emergency response teams arrive at the scene as fast as quickly as possible.  It would also allow for those first on site to estimate how long it would take for reinforcments to arrive. 

METHODOLOGY

My first step was to create a road layer for Manhattan.  Using the base provided from mn_streets ShapeFile I reclassed my data into Major, Secondarily Major, and Minor roads.  Once this layer was imported and rasterized I assigned a value of 2 or 3 to each major or secondarily major road.  Having over 11,000 road segments to assign values to I filled in the 2 and 3 values using filter and streetnames in the database workshop.  Then exported the table so I could fill in the remaining 5000+ values as 1.  After having reassigned each street a value, I linked the man_class.avl to the road layer using assign.

road class cartographic model
 

Next was to select the schools which would be used in the analysis.  The schools had to meet the minimum 1000 student enrollment criteria.  I linked the mn_schools.mdb to the school layer which I had imported and rasterized and reclassed the school based on capacity.  This left me with 12 schools from which to choose.  I chose one school which would represent Upper Manhattan (Alexander Humbolt School) and one to represent Lower Manhattan (Hernando Desoto School).  From their ID's I created an edit file and assigned values to only those two schools creating school_sel. 

selected schools cartographic model
 

Friction value files were now needed for each of the traffic time zones.  I set 80km/hr as my max speed which an emergency response vehicle could obtain and set that at a friction of 1.  All other speeds travelled were set at a friction proptional to how much longer it would take the vehicle to traverse the same distance.  One optimal surface was created in which emergency response vehicles could travel 80km/hr, down all road classes using the costpush option from distance operators.  This surface would serve as a reference.  Three other surfaces were created for each traffic time zone.  From this point, it becomes apparent into which response time each firestation or hospital falls.

NOTE: To change my distance surface from a distance layer to a time layer, I first used scalar to change the distance from the screen distance to a real world distance based on the resolution of the layer.   Once the layer was in real world distances I reclassed the layer using the distance which could be travelled going 80km/hr in 5 minute intervals from 5 minutes to 30 minutes.  I was able to do this because I already incorporated the difference in speeds on each route into the friction layers. 

response times based on traffic zone time of day cartographic model

• zone 0
• zone 1
• zone 2
• zone 3

For the optimal route layers I found the fastest route between the school and the three closest firehalls and the three closest hospitals as these would be the first to respond in the case of an emergency.  The positions of many of the firehalls and many of the hospitals did not fall exactly on top of the roads layer, after being converted from vector to raster.  Each one then had to be accurately digitized so that it would intersect the roads layer.  From that point it was easy to run the least-cost pathway and produce optimal routes to the schools. 

optimal response routes cartographic model