How many streetlights and miles of bike route in each district?

Nota:

This example use case presents an approach to using ArcGIS to find out how many streetlights and how many miles of bicycle route are in each maintenance assessment district. The information will allow the city to select districts that can help maintain the infrastructure. While the data is real, the scenario, analysis, and resulting decisions are hypothetical. The purpose of the example is to illustrate the type of problem that can be addressed by summarizing point and line features within area features.

So many projects, so few dollars

The city is underfunded on infrastructure projects and is facing a backlog of at least $900 million. The projects include everything from street paving to streetlight maintenance, flood channel clearing, and construction of new storm drains. The city council recently voted to create an Infrastructure Committee to focus on the backlog. Their goal is to cut red tape and process contracts more quickly. They will also look at ways to get the community involved in doing some of the maintenance work so the city can focus its limited funds on construction projects.

Seeking maintenance help

One approach they are considering is working with the city's maintenance assessment districts to cover some of the maintenance costs. The districts were set up by local property owners in various neighborhoods to assess themselves for services above and beyond those provided by the city for street cleaning, median maintenance, and streetlights, among other things. There are over fifty of the districts in the city, covering both business and residential neighborhoods.

Maintenance assessment districts

The Infrastructure Committee decides to approach the districts about streetlight maintenance, as this impacts the safety of the neighborhoods. The city is in the process of converting from high-pressure sodium lights to energy-efficient LED streetlights when the lights need repair or replacement. The committee will encourage the districts to take on this conversion, and the city will pass the energy savings to the property owners in the form of rebates on their property tax assessments.

Close-up view showing locations of streetlights with several of the maintenance assessment districts

The committee is also interested in maintenance of the city's designated bicycle routes, which are becoming more and more popular. Many of the routes pass through maintenance assessment districts, so the committee will also approach the districts about paying for the extra street cleaning needed to keep the routes clear and about providing and maintaining signage.

Close-up view showing locations of bicycle routes with the maintenance assessment districts

It will likely take some convincing, as well as incentives, to get cooperation from the districts. Due to budget cuts the city council is operating with a skeleton staff, so the committee is assigned a single staff person. Rather than trying to work with all 55 districts at once, the committee's assigned staffer will start with 10 or 15 districts and see how receptive they are. She decides to identify the districts that are in the middle of the pack in terms of number of streetlights. If she picks districts with too few streetlights the program won't have much impact; too many and the assessment district is more likely to balk at the cost. She'll take the same approach for the bike routes.

Selecting the districts to contact

The staffer uses ArcGIS to do the analysis. ArcGIS allows her to calculate the number of point features or total length of line features falling within each area-in this case, the number of streetlights and miles of bike route in each district.

The staffer creates a new map in ArcGIS. From the online countywide GIS database, she adds the city's maintenance assessment districts and streetlights, and bike routes for the county. She summarizes the number of streetlights in the assessment districts and does the same for miles of bike route.

She then maps the districts color coded by the calculated values. Using a quantile classification with seven classes will create a map with about eight districts in each class. She can then identify the districts that fall in the middle.

Maintenance assessment districts symbolized by the number of streetlights in each

Maintenance assessment districts symbolized by miles of bicycle route in each

The middle value range for streetlights is 165 to 250, and for bicycle routes it's 2.3 to 3.9 miles. The staffer filters the two result layers to find the districts that fall in these ranges.

The districts that have between 165 and 250 streetlights

The districts that have between 2.3 and 3.9 miles of bicycle routes

As it turns out, two of the districts are on both lists, so there are 14 districts to contact in total. That's a manageable number to start with. The staffer gives the list of candidate districts to the members of the Infrastructure Committee. The committee gives its approval to go ahead and asks her to report back on the initial response from the districts at the next meeting of the committee in four weeks.

Mixed results

At the meeting, the staffer reports that the response was varied - a couple of the districts that are mainly composed of businesses along commercial strips are receptive to paying for upgrades to the streetlights and getting the energy rebates, but they have no interest in maintaining the bike routes. One of the suburban districts is considering maintaining the bike routes but is not interested in upgrading the streetlights. The other districts have no interest. Undeterred, the committee directs the staffer to pursue working with the districts that are interested in the hope that if the approach is successful, other districts may be more willing to join in the program.

Workflow using ArcGIS Online

Find the maintenance assessment districts in the midrange of values in terms of number of streetlights

1. Use the Summarize Within tool to count the number of streetlights in each maintenance assessment district.

   

2. Change the symbology to use a Quantile classification with seven classes.

   

3. Filter the resulting layer to find the districts containing between 165 and 250 street lights.

   

Find the maintenance assessment districts in the midrange of values in terms of miles of bicycle route

1. Use the Summarize Within tool to sum the length of bicycle routes in each maintenance assessment district.

   

2. Change the symbology to use a Quantile classification with seven classes.

   

3. Filter the resulting layer to find the districts containing between 2.3 and 3.9 miles of bicycle routes.

   

Workflow using ArcGIS Desktop

Find the maintenance assessment districts in the midrange of values in terms of number of streetlights

1. Use the Tabulate Intersection tool to count the number of streetlights in each maintenance assessment district.

   

2. Join the summary table to the attribute table for the maintenance assessment districts.

   

3. Map the maintenance assessment districts by number of streetlights, using a Quantile classification with seven classes.

   

4. Use Select By Attributes with the maintenance assessment districts to find the districts containing between 165 and 250 streetlights.

   

Find the maintenance assessment districts in the mid-range of values in terms of miles of bicycle route

1. Before summarizing the bicycle routes, remove the existing join (the streetlight summary table) from the maintenance assessment district layer. Now use the Tabulate Intersection tool to count the length of bicycle routes in each maintenance assessment district. Specify miles as the output units.
2. Join the bicycle route summary table to the attribute table for the districts.

   

3. Map the assessment districts by miles of bicycle route, using a Quantile classification with seven classes.

   

4. Use Select By Attributes with the maintenance assessment districts to find the districts containing between 2.3 and 3.9 miles of bicycle route.

   

Automation using ArcGIS Desktop

The ArcGIS Desktop workflow can be automated, as shown in this diagram.

Nota:

The model is available for download in the GPK using the button at the top of this case study.

Workflow using ArcGIS Pro

Find the maintenance assessment districts in the midrange of values in terms of number of streetlights

1. Use the Tabulate Intersection tool to count the number of streetlights in each maintenance assessment district.

   

2. Join the summary table to the attribute table for the maintenance assessment districts.

   

3. Map the maintenance assessment districts by number of streetlights, using a Quantile classification with seven classes.

   

4. Use Select Layer By Attribute with the maintenance assessment districts to find the districts containing between 165 and 250 streetlights.

   

Find the maintenance assessment districts in the mid-range of values in terms of miles of bicycle route

1. Before summarizing the bicycle routes, remove the existing join (the streetlight summary table) from the maintenance assessment district layer. Now use the Tabulate Intersection tool to count the length of bicycle routes in each maintenance assessment district. Specify miles as the output units.

   

2. Join the bicycle route summary table to the attribute table for the districts.

   

3. Map the assessment districts by miles of bicycle route, using a Quantile classification with seven classes.

   

4. Use Select Layer By Attribute with the maintenance assessment districts to find the districts containing between 2.3 and 3.9 miles of bicycle route.