Network Analyst - Analyze Week

Special Topics - Project 1 Week 2

Using the data that was prepared last week, this week the assignment was to create a map with evacuation routes for patients from Tampa General Hospital to other hospitals, evacuation routes from downtown Tampa, supply routes from the National Guard armory to the shelters, and the service areas for each of the shelters.

To accomplish these analyses I created a new network dataset and added the attributes Seconds, to create fast and simple routes, FloodPublic, to calculate routes to avoid flooded streets closed to the public, and FloodEmer, to calculate routes for emergency vehicles which may need to use flooded streets to respond to emergencies but will otherwise avoid them, verifying the evaluators had the correct type and value for each of the attributes.

Because of its location on Davis Islands and the very low elevations there, Tampa General Hospital will need to be evacuated before the hurricane hits.  Memorial Hospital of Tampa and St. Joseph’s Hospital were chosen to accept those patients.  Using Network Analyst’s New Route feature, routes were created from Tampa General Hospital to each hospital, ensuring Impedance was set to Seconds and Restriction only to Oneway to be sure the shortest time route was selected to each.

The US Army National Guard will deliver the emergency supplies from their armory to the local storm shelters.  Because the supplies may not arrive until after the storm hits the routes have been designed to avoid flooded roadways.  Three new routes were created from the armory to each of the shelters.  For these routes the Restrictions were set to FloodEmer to avoid flooded streets as much as possible, but to use them if necessary.

Multiple evacuation routes were also created for downtown Tampa because it is so heavily populated.  The DEM polygon layer, which was used in the Prepare data to specify the predicted flood elevation levels, was also used here with a new Short Integer attribute field added named ScaledCost so groups of elevations could be used with the Impedance attribute to determine the drive times affected by flooding in order to determine the best routes to take to the shelter located at Middleton High School.

To cut down on confusion and uncertainty by the general population the map has been color coded by the shelter service area to make it easier at a glance to tell what shelter they can get to the quickest.  This was done through the New Service Area Network Analyst feature using the shelter points as Facilities, setting the Impedance to Seconds and the Default Breaks value to 10,000 to make sure all areas would be included in the analysis, and the Direction to Toward Facility, with Not Overlapping selected for the polygons, which were then symbolize with different colors.