Multi-Layers OR Function

Updated by PolicyMap

The default search of the Multi-Layer feature allows users to find places that intersect up to 5 data layers. This query is called an AND function which only shows places that meet the "intersection" of each data layer added. This query is useful to identify exact places that meet specific data criteria.

If you select the locations around places that meet the AND you can see that some places meet a few or none of the data layers added. This could give users more information on the areas matching the AND query.

AND OR option in multi-layer legend

Users can select the OR function in the legend to change the query for the data layers to the "overlay". This will over the overlap of data layers. The OR function introduces colors and patterns to show how 1, 2, or more data layers might over lap. The OR function can show more information about the surrounding area of the places that met the AND function.

In this example, we show two census tracts in Knoxville, TN that have at least 15% of the households do not own a car, 25% are person 65 or older living in poverty, and are in Medically Underserved areas. Both close to local hospitals.

If we change to query to OR, we can see that more tracts north are captured but just missed on criteria. Many of the northern census tracts are Medically Underserved but miss the car ownership or over 65 living in poverty. Some tracts are a combination of Medically Underserved and a variation of the two other data layers. We can see that there is potentially more need around the census tracts that met the AND function.

animation of Knoxville example

In another example, we should a handful of neighborhoods in New Orleans that are in high risk flood zones, at least 20% of the homes were built before 1940, and 25% are housing units with one or more physical or financial selected conditions.

A "selected condition" includes lacking complete plumbing facilities, lacking complete kitchen facilities, having 1.01 or more occupants per room, having selected monthly owner costs as a percentage of household income greater than 30 percent, and having gross rent as a percentage of household income greater than 30 percent.

These homeowners might have many potential challenges ahead from home repair, to flooding, to general repair. Some financial outreach and planning might help these homeowners for future events.

if we change the query to OR, we see that much of New Orleans have homes built before 1940 and have one or more selected conditions but not in a high risk flood zone. While flooding might not occur immediately, this entire area would benefit on planning to face upcoming costs of home repair and maintenance. The OR query allowed us to expand the search beyond the limited boundaries of flood zones.

animation of New Orleans example

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