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PolicyMap: 3-Layer Maps

Instructional guide on how to use PolicyMap, a Graphic Information System (GIS) data and mapping tool.

3-Layer Maps

3-Layer Maps allow you to create a map with up to three data layers.

1. Go to the 3-Layer Maps tab at the top of the screen.
 


2. Enter a location in the Location search bar. (The 3-Layer Maps feature requires the map to be zoomed in, so you need to select a location first.)
 


3. Add a data layer from the data menu or data search bar above the map.
 


4. Adjust the year, the variable, and geography types by clicking on Edit Layer, and move the sliders or enter criteria values to set the ranges. It is important to adjust the sliders to reflect the majority of data points and disregard outlying information. Adjusting the lower end of the slider above 0% with respect to percentages will get rid of outlying information that could skew the results. If you do not adjust the ranges, it could show too many results.
 


 

In this example directly below, a 0%-100% range gives you all areas that have zero percent and one hundred percent single family homes. It also defaults to showing you a range of home prices that are unrealistically low and $8,000,000.
 


Adjusting the sliders can give you more realistic results. As an example, you could look for the areas where there are relatively affordable single-family homes. This can be achieved by searching for areas where there are at least 25% single family homes under $1,000,000.
 


5. To add additional criteria, choose another data layer from the data menus or data search bar.

6. Select any area on the map to see values for all the layers you have added.