Thematic MappingTom E SellstedCity of Yakima, WashingtonTsellste@ci.yakima.wa.us

SafetyNet Conference

What is Thematic Mapping?

A thematic map enables statistics to speak through visual representation of the facts and further enables their geographic interpretation.

Burglaries

Basic Pin Mapping Can select by Date and/or Time

Range Could be for a specific area of

interest

Sex Offenders

Use of color to designate level Use of marker size to designate

severity of level

Events Near a Location/Person Proximity to a defined address or

person Types of Events

Density Mapping Defined areas – can be large or small Shading by the occurrence of a selected

type of event Darker indicates a higher concentration

of events Lighter shade indicates a lower

concentration of events

Repeat Calls Locations of 10 or more Size indicates the number of repeat

calls Color could also be used Could show just top Repeat Call

locations

Hot Spot Mapping

Surface Density or Raster Repeating call locations Proximity to other events

Stolen/Recovered Vehicles

Defined Date/Time Range Color for Stolen or Recovered Draw link between associated

cases Look for trends

Time Series Animation Ability to look for trends based on time Date/Time Range Can do Individual or Cumulative range

study Time range can be: hour, day, month or

year

Street Capacity Analysis

Displaying Multiple Themes Correlation between Themes Trying to not Over Visualize…

Intersection Analysis

Have Multiple Meanings at a point Can take time to digest…

Pedestrian Accidents

Different Marker Symbols

Severity of Injuries

Marker Size Marker Color Color Coded Descriptive Table

Total Collisions

Marker Size Labeling Markers Descriptive Summary Table

Contributing Factors

Stacking Markers Using Sizes and Marker Styles

Type of Collisions

Use Pie charts Size indicates Number Slices indicate Frequency of Type