Gallery – Geospatial Analyses via ArcGIS
Geographic Information Systems (GIS) is an innovative way of visualizing data spatially to understand
relationships, patterns, and trends. The Third Coast CFAR offers GIS services to members through the
BSIS Core. This gallery includes several examples of the types of maps useful in HIV research. If you
are interested in using geospatial analyses in your work, please contact a CFAR research navigator
at cfar@northwestern.edu.
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Descriptive MapsDescriptive Maps are used for reference of geographic locations, or places.
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Choropleth MapsChoropleth Maps use aggregate data to depict geographic distribution
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Categorical MapsCategorical Maps are used to show data or places that are different in kind rather than in amount. Typical ways of depicting these differences is through color, symbol type, or size.
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Buffer Analysis shows data within a specific distance or time of a pointBuffer Analysis
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Density MapsDensity Maps show high and low density areas of specific points.
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Combining Map TypesTo show possible relationships between two types of geographic data. Great for brainstorming new research questions and understanding resource allocations.
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Story Slider maps are interactive and allow you to show various types of maps across two different data points.ArcGIS Online: Story Slider MapsThey are hosted on the Northwestern ArcGIS online platform. A link to the map for distribution will be provided.
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Story Map Series are interactive and allow you to present a series of related maps, videos, images and text in a story format.ArcGIS Online: Story Map SeriesThey are hosted on the Northwestern ArcGIS online platform, but offer an HTML code block for your website.
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Hot Spot Analysis identifies statistically significant hot spots and cold spots for a specific attribute.Spatial Statistics: Hot Spot Analysis
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Emerging Hot Spot Analysis identifies statistically significant hot spots and cold spots for a specific attribute over a period of time to identify trends.Spatial Statistics: Emerging Hot Spot Analysis
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Spatial Statistics: Average Nearest NeighborAverage Nearest Neighbor measures the distance between a feature centroid (or point) and its nearest neighbor's centroid (or point). It then averages all the distances to determines if the distance between the points are based on random chance.This Average Nearest Neighbor is computed from the CTA Bus Stops Map (see Density Map example)
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Spatial Statistics: Moran's I Spatial AutocorrelationMoran's I measures spatial autocorrelation, or correlation of a variable with itself through space, based on feature locations and values simultaneously. To measure this, it needs a set of features and an associated attribute. It then evaluates whether the pattern expressed is based on random chance.This Moran's I Spatial Autocorrelation is computed from the CDPH 2013-14 Average Annual HIV Infections Map (see Choropleth Map example)