Are liquor stores too close to schools, libraries, and parks?

Note:

This example presents an approach to using ArcGIS to find out if any liquor stores in a city are within 1,000 feet of places where children congregate. The information will help the city monitor and regulate liquor stores. While the data is real, the scenario, analysis, and resulting decisions are hypothetical.

Too many liquor stores

The state department of alcoholic beverage control has recently notified the city manager that there is a high number of liquor stores in the city given its size, and it is placing a moratorium on new licenses. At the same time, the police department reports an increase in complaints from citizens about nuisance activity near liquor stores, including public drunkenness, disturbing the peace, and vandalism. The police department has also noticed an uptick in crimes such as assault and theft near the stores.

Liquor stores within the city boundary. You have to admit, there are quite a few.

The city considers an ordinance

Due to concerns with the number of liquor stores in the city and the related undesirable activity, the city council unanimously passed an initiative to review all the policies relating to liquor sales in the city. The council is particularly concerned about the impact of the prevalence of liquor stores on the city's children.

Not content to wait for the full review, one council member has written an ordinance based on ones in place in other cities around the state. The draft ordinance includes limiting the locations of liquor stores to areas more than 1,000 feet from places where children congregate—specifically, schools, libraries, and parks. Under the ordinance, any such stores will face more stringent regulations, such as limits on advertising, and will be closely monitored to prevent sales to minors. If they don't meet certain performance standards their licenses will be revoked.

Finding noncompliant liquor stores

The council member asks the city planner to find out if any existing liquor stores are within this distance. For the analysis, the planner's staff members create buffers of 1,000 feet around each liquor store. The staff members display the buffers on a map with schools, parks, and libraries.

1,000-foot buffers around liquor stores in the city, with locations of schools, parks, and libraries

As it turns out, one liquor store is within 1,000 feet of one of the city's libraries. The same liquor store is within 1,000 feet of a school and a park. One other liquor store is also within 1,000 feet of a school and a park, while three additional liquor stores are within 1,000 feet of a school. If the ordinance passes, all five liquor stores will face the new regulations, which will be backed up by law enforcement. The staff can select a buffer to get information about the feature it was created around, such as the name and address of the store.

Several liquor stores are within 1,000 feet of a school, library, or park and are not compliant with the proposed ordinance. This particular liquor store is within 1,000 feet of all three.

The council member sponsoring the new ordinance presents the results of the analysis at the next council meeting in an effort to build support for passing the ordinance. The council votes to move forward with the ordinance and directs the city manager to undertake a legal review of the proposed ordinance and schedule a public hearing. It also presses the city manager to complete the full review of liquor sales within the next six weeks.

Creating a restricted zone

Anticipating that the ordinance will eventually be enacted, the planning staff members decide to create a map showing the area off-limits to any future liquor stores. To make the map, the staff members first create 1,000-foot buffers around schools, libraries, and parks, in turn. They then combine the buffers into a single layer. If and when the state moratorium is lifted, the council members will be able to quickly see if the proposed location for any new liquor store is within the restricted zone.

Restricted zone around schools, parks, and libraries—new liquor stores cannot be located in this zone.

The city planner presents the map of the restricted zone to the council members at their next meeting. They are impressed, but anticipating pushback from liquor store owners—and the business community in general—about the new restrictions and regulations, the council members ask the planning staff to do some additional analysis. They would like to know how much of the city is outside the restricted zone. Using ArcGIS, the planning staff members summarize the amount of the city within the restricted zone—about 4.8 square miles. They then subtract this number from the area of the city (14.5 square miles) to get the amount outside the zone (9.7 square miles). So about two-thirds of the city is outside the restricted zone. They enter the numbers into a spreadsheet and create charts to make it easier for the council members to visualize. They also create an accompanying map showing the portions of the city inside and outside the restricted zone.

With this information, the council members are confident they can defend their support for the ordinance.

Workflow using ArcGIS Online

Find liquor stores within 1,000 feet of a school, park, or library

1. Use the Create Buffers tool to create 1,000-foot buffers around existing liquor stores.

   

Create a restricted zone around schools, parks, and libraries

1. Create 1,000-foot buffers around schools.
2. Create 1,000-foot buffers around libraries.
3. Create 1,000-foot buffers around parks (parks are areas and so have an additional option: you can include the park in the buffer, or create a donut around the park).

   

4. The buffers for the three layers can be displayed together but are in separate layers. Use the Overlay Layers tool with the Union option to combine them. First combine the school and library buffers (the Overlay Layers tool is in the Manage Data toolset).

   

5. Use the Overlay Layers tool with the Union option again to combine the previous overlay with the parks buffers.

   

6. Now use the Dissolve Boundaries tool to create the restricted zone (the Dissolve Boundaries tool is also in the Manage Data toolset).

   

Calculate the amount of the city outside the restricted zone

1. Use Summarize Within to calculate the amount of the city within the restricted zone. Specify that area be calculated in square miles. Then show the table for the summarized layer to get the area. Compare it to the area of the city (contained in the city boundary layer) to calculate the portion of the city outside and inside the restricted zone.

   

2. Use the Overlay Layers Erase tool to remove the portion of the city covered by the restricted zone. The erased layer can be displayed on top of the full city boundary layer to create the map showing areas of the city outside and inside the restricted zone.

   

Workflow using ArcGIS Desktop

Find liquor stores within 1,000 feet of a school, park, or library

1. Use the Buffer tool to create 1,000-foot buffers around existing liquor stores. Specify Distance as Linear unit with a value of 1,000 feet, and specify the Dissolve Type as NONE.

Create a restricted zone around schools, parks, and libraries

1. Use the Buffer tool with the schools, libraries, and parks layers in turn. Again, specify Distance as Linear unitwith a value of 1,000 feet, and specify the Dissolve Type as NONE.

   

2. The buffers can be displayed together but are in separate layers. Use the Union tool to combine them.

   

3. Now use the Dissolve tool to create the restricted zone.

   

Calculate the amount of the city outside the restricted zone

1. Use the Identity tool with the city boundary and the restricted zone. Identity clips the restricted zone (buffer_union_dissolve) at the city boundary and creates an output layer with two features: the area inside the zone and the area outside.

   

2. The Identity output layer can be used to create the map showing the portions of the city inside and outside the restricted zone. Use the charting capabilities in ArcGIS Desktop to create the pie chart from the values in the table, or copy the area values to a spreadsheet and create the chart there.

Automation using ArcGIS Desktop

The ArcGIS Desktop workflow can be automated by creating a model, as shown in this diagram.

Note:

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

Workflow using ArcGIS Pro

Find liquor stores within 1,000 feet of a school, park, or library

1. Use the Buffer tool to create 1,000-foot buffers around existing liquor stores. Specify Distance as Linear unit with a value of 1,000 feet, and specify the Dissolve Type as No Dissolve.

   

Create a restricted zone around schools, parks, and libraries

1. Use the Buffer tool with the schools, libraries, and parks layers in turn. Again, specify Distance as Linear unitwith a value of 1,000 feet, and specify the Dissolve Type as No Dissolve.

   

2. The buffers can be displayed together but are in separate layers. Use the Union tool to combine them.

   

3. Now use the Dissolve tool to create the restricted zone.

   

Calculate the amount of the city outside the restricted zone

1. Use the Identity tool with the city boundary and the restricted zone. Identity clips the restricted zone (Buffer_Union_Dissolve) at the city boundary and creates an output layer with two features: the area inside the zone and the area outside.

   

2. The Identity output layer can be used to create the map showing the portions of the city inside and outside the restricted zone. Use the charting capabilities in ArcGIS Pro to create a bar graph from the values in the table, or copy the area values to a spreadsheet and create the chart there.