by Christy Jacobs Walk Distance Maps & Analysis Using Network Analyst by Christy Jacobs

What’s a walk distance map? Walk Distance Polygons School A walk distance map is a map of one or more individual polygons around each school of interest. Each polygon is created around a school and designates an area of a certain distance on the street network. A lot of times these polygons are used to analyze and count students that are within the designated walking distance of each school.

Introducing Network Analyst Network Analyst allows you to create and manage network data sets and generate routing systems Use for network-based spatial analysis - location analysis - spatial interaction modeling

Using Network Analyst – Analyses Types Finding the best route - the shortest or most scenic route from set location to set location Finding the closest facility Finding a service area - finding the service areas around facilities based on a cost attribute (length/distance, time) Creating an OD (Origin-Destination) Cost Matrix - used for routing of multiple originations to one destination and manages individual impedances for each origination

What’s a Service Area in Network Analyst? - the area around a facility, based on a network, that the facility can service depending on the cost attribute Understanding Service Areas In this map in Network Analyst terms : The cost attribute is miles, schools are the facilities and the service area is the 1- mile area shown as a polygon on the street network in the area around the school Service Area Polygon Facility Point In this map: Each blue area displays the area within 1 mile of each school, based on the street network around the school

Using Network Analyst How can Network Analyst help me in my work? Create walk/drive distance maps to show distances and/or routes to and from facilities - cost attributes can be shown as length, like in miles, or time, like in minutes - use Service Area creation for this Create multiple street routing scenarios for more sophisticated analysis of potential new facility locations or attendance boundary adjustments - could use Routing, Closest Facility or OD Cost Matrix for this depending on variables used and outcome desired

Creating Network Analyst Datasets Before beginning to work with Network Analyst to create network routing and areas, you have to create a network dataset to work with:

Creating Network Analyst Datasets In ArcCatalog, right click on the dataset that contains the data to be used in the Network dataset New Network Analyst Wizard Go to “New”, then click on “Network Dataset”

Creating Network Analyst Datasets Name the Network Dataset Choose the participating data Connectivity settings

Creating Network Analyst Datasets Modeling Turns Elevation Data Settings

Creating Network Analyst Datasets Choose Cost Attributes Can Use Shape Length as a Cost Attribute

Creating Network Analyst Datasets Set Driving Directions, if desired Summary Click on “Finish” and then when prompted to “Build” the network dataset, select “Yes”

Introducing the Network Analyst Extension toolbar Check on Network Analyst Toolbar Note: Be sure the extension is turned on in Tools – Extensions before bringing in the Network Analyst toolbar

Navigating the Network Analyst toolbar Choose Network type Create Network Location Tool Select/ Move Network Location Tool Active Network Dataset Network Identify Tool Solve Button Build Button Show/Hide Network Analyst Window

Network Analyst in ArcMap Network Analyst Window Network Analyst Layers

What’s a Service Area in Network Analyst? - the area around a facility, based on a network, that the facility can service depending on the cost attribute Review of Service Area Features In this map in Network Analyst terms : The cost attribute is miles, schools are the facilities and the service area is the 1- mile area shown as a polygon on the street network in the area around the school Service Area Polygon Facility Point In this map: Each blue area displays the area within 1 mile of each school, based on the street network around the school

I have walk distance polygons of 1 mile. Now what?? Using Service Areas to Analyze Walk Distance and Student Location Bring in your Bring in your students file and select, query and analyze the students that are within the walk distances polygons or outside students file and select, query and analyze the students that are within the walk distances polygons or outside Use “Select by Location” to isolate students that reside within the polygons

Using Network Analyst Let’s use Network Analyst to create a service area that displays a walk/drive distance of 1 mile around school locations, then select students that are within those service area polygons