How To Guide: Create An Internal/External (IIEE) Analysis With StreetLight InSight
This tutorial shows how to easily create an Internal/External (IIEE) analysis using StreetLight InSight. This type of analysis allows you to calculate the share of trips in a Zone that are fully internal (II), fully external (EE), inbound (EI), or outbound (IE).
For this tutorial, our area of interest is Parsippany-Troy Hills Township, located in Morristown, New Jersey. With four major highways running through the town, external-external (EE), or “pass through” trips comprise a large volume of the total trips in the area. StreetLight’s O-D analysis will help to understand this share of pass through trips compared to fully internal trips, and can even be used to examine the share of external trips by each highway gateway.
This tutorial contains supporting files. Please click here to download them.
Step 1: Create Your Zone Sets
1a. Create the first Zone Set one of two ways; by uploading a shapefile or by drawing the Zones. No matter how you choose to create your Zones, you will ultimately have two Zone Sets: one with pass-through gateways, and one containing the city or area of interest that is designated as not pass-through.
1b. In this tutorial, we will first create the Zone Set that is not marked as pass-through, by uploading a shapefile of the area of interest. If a shapefile is not available, you can draw polygons within StreetLight InSight. During upload, when mapping the fields in your shapefile to StreetLight InSight, choose “Always No” under “Zone is Pass Through”. Name the Zone Set “Parsippany” and click continue.
1d. Next, create a new Zone Set named “Parsippany Gateways”. Click on “Draw New Zone”. To ensure that the gateway Zones that you draw are on the boundaries of the area of interest, use the tool called “View Other Zone Set”.
Search for the Zone Set you just created, “Parsipanny”, and zoom into the area on the map.
Using the boundaries from this Zone Set as guidance, create a “gateway” Zone on each major ingress/egress road, preferably State Route or Interstate Highways.
When creating gateway Zones, draw small polygons that are perpendicular to the road. Clicking “Show OSM Layer” will populate the map with the Open Street Map, so that you can verify that the polygon only captures the road of interest. Make sure to mark these Zones as pass through. If setting a direction, make sure to also mark as bi-directional.
After repeating this process for all major ingress/egress roads, your Zone Set will have multiple gateway Zones on the perimeter of the area of interest.
Step 2: Set Up the IIEE as an ”Origin-Destination Analysis" Project
2a. Go to the “Projects” tab and create a Project named “Parsippany IIEE Project”. Then designate its Project Type as “O-D Analysis”. The type of travel and data source will auto-populate using Personal travel and Location-Based Services with Pass-Through.
2b. Under “Available Zone Set”, click “Parsippany” Zone Set to highlight it, then click the right arrow to assign it as an Origin Zone Set and a Destination Zone Set. Do the same thing for the “Parsippany Gateways” Zone Set. If necessary, adjust the day part, data period, and other parameters under the “Project Options” tab.
2c. Click “Confirm” to run the Project.
Step 3: Download Results in StreetLight InSight
3a. Once your Project is complete, download the Metrics and complete your IIEE analyses using Microsoft Excel. To download your Metrics, go to the “Manage Projects” section, and click on the “All Projects” tab. In the Actions Column, click the Download icon.
3b. Select which files you want to download. For IIEE, you must select the “O-D Metrics CSVs”. The other downloads are optional. Click “Download” once you’ve made your selection.
Step 4: Utilize Results
4a. Open the folder you downloaded and the CSVs and shapefiles you selected will be there. There will also be a README and Project files text.
4b. Create a new column (column R) named “Origin = Dest”. Trips identified with the same Pass-through Zone for the origin and destination need to be filtered out for accurate results. Copy and paste this code into cell R2 and copy the formula down for the entire column:
4c. Create another new column (column S) named “Trip Type”. Set up filters on the whole worksheet by going to the “Data” tab, and click “Filter”. Then, filter columns D and I (which designate the Origin and Destination Zones as pass-through with “yes” and not pass through as “no”). Label each row as one of the four trip types: internal-internal (II), internal-external (IE), external-internal (EI), and external-external (EE).
- Internal-internal: Origin and Destination Zones are not pass-through
- Internal-external: Origin Zone is not pass through, Destination Zone is pass-through
- External-internal: Origin Zone is pass through, Destination Zone is not pass-through
- External-external: Origin and Destination zones are pass-through
4d. Once all rows are appropriately tagged with a trip type, select the entire worksheet again and create a pivot table. Filter by the fields shown.
If you have never worked with pivot tables before, here is an introduction to pivot tables by Microsoft.
Using the Trip Type as the Row Labels, you can easily visualize the percentage of each type of trip with a table, or pie chart, or other graph. Using the PivotTable Fields, you can also look at other metrics, such as the trip type percentages by Origin or Destination Zone.