BRFSS Maps: Visualizing Oral Health Surveillance Data

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BRFSS Maps Visualizing Oral Health Surveillance
Data

• James B. Holt, M.P.A., Ph.D.
• Centers for Disease Control and Prevention

Pittsburgh, PA May 4, 2005
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Outline of Presentation

• Basic concepts data tables vs. maps
• Purpose and functionality of BRFSS Maps
• Future enhancements to BRFSS Maps
• Summary

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Data Tables vs. Maps

• Different ways of looking at the data
• Specific values (tables) or spatial patterns in
  the data (maps)?
• In other words detail vs. simplification
• Data for analysis (tables) or data for
  visualization (maps)?
• Access to ancillary information (tables)?
• Confidence intervals
• Cell sizes
• Comparison of two or more variables

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What to Use Data Table or Map?
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Multivariate Relationships Tables
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Multivariate Relationships Map Comparison
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Multivariate Relationships Multivariate Map
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Maps Static vs. Interactive

• Static one-of-a kind snapshot
• If data are updated - map is outdated
• Okay if you anticipate a one-time need
• Can be produced in a graphics package or a
  geographic information system (GIS)
• Interactive dynamic
• If data are updated map automatically updates
• Good for one-time needs as well as periodic
  updates
• Can be produced via a GIS, with internet-enabled
  interactivity, controlled by end-user

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BRFSS Maps

• Interactive
• GIS-enabled
• Internet-based mapping application
• Visual depiction of BRFSS data
• States
• Metropolitan and Micropolitan Statistical Areas
  (MMSA)

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Purposes

• Visualization and exploratory spatial data
  analysis
• Highlight regional patterns and interstate
  variations
• Prompt interesting research questions
• BRFSS data in a GIS-friendly format
• Encourage the use of geographically-referenced
  risk factor data

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Functionality

• View state and MMSA data together or separately
• User selectable class breaks
• Zoom, pan, and prevalence rate retrieval
• User selectable labeling
• Image downloading
• GIS data downloading
• Access to mapping guidance

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BRFSS Maps Development Timeline

• Conceptual development July 2003
• Technical planning layout October 2003
• User feedback February 2004
• Version 1.0 August 2004
• Enhancement planning continuous
• Version 1.1 January 2005
• Version 2.0 June 2005, expected

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Initial Map Screen
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Prevalence Data
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User Control over Mapping Options

• Natural breaks
• Quantiles
• Equal intervals
• Standard deviations

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Mapping by Standard Deviations
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Mapping by Quintiles
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Zooming and Panning
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Saved Graphic Image
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Download GIS Data
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New DevelopmentsSince Initial Release

• Improved internet response time in Version 1.1
• Adapted for rapid response to emerging public
  health issues (e.g., influenza vaccination
  surveillance, 2004-05)

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System Components

• Web server
• IIS (Microsoft web server software)
• ASP.Net (webpage development software)
• Database server
• SQL Server 2000
• NCCDPHP data repository
• GIS server
• ArcIMS
• Internet GIS development
• map generation

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System Architecture
Get the data
Send map request
I want to see a map!
Web Server
HTTP request
Retrieve dataset
image streamed back
Web Browser
Data being mapped are passed to GIS service
image streamed back
ArcIMS generates map image
GIS Server
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GIS Web Service

• Mapping capability easily integrated into
  existing Web sites
• Increased data security
• GIS service does not require database access
• Mapped data sent with each map request
• Sensitive datasets are not exposed
• Performance enhancement
• Very fast response time
• No lengthy browser downloads

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BRFSS Maps Future Enhancements

• Version 2.0
• New user interface
• Redesigned map frame
• New visualization tools
• Versions 3.0 and 4.0
• Visualization of multivariate relationships
• Visualization of county-level data

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New User Interface and Map Frame
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New Visualization Tools

• Natural breaks
• Quantiles
• Equal intervals
• Standard deviations
• Manual breaks

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Visualization of Multivariate Relationships

• Many options
• Map-to-map comparison
• Bivariate map (e.g., Census map)
• Proportional symbol over choropleth
• Stacked bars over choropleth
• Conditioned choropleth
• Would require cognitive testing and technical
  feasibility study

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Multivariate Relationships Multivariate Map
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Mapping County-level BRFSS Data

• Data availability (sample size)
• Statistical noise
• Spatial smoothing small area ests.
• Purpose and limitations of maps of spatially
  smoothed sample data
• Pattern recognition
• Rate retrieval

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Raw Data Counties 50 interviews

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Raw Data All Counties
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Spatially-Smoothed All Counties
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Isopleth Map Spatially-Smoothed
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Cognitive Issues

• Rate retrieval and recall
• Pattern recognition and recall
• Map comparison
• Visual dominance
• User preferences

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Technical Issues

• Data-related
• Cartography-related
• Internet-related

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Summary

• BRFSS Maps enables visualization of oral health
  and other public health surveillance data
• Development emphasized usability and utility
• Future developments will focus on visualizing
  multivariate relationships, county-level mapping
  and additional functionality
• Innovation in mappingnot merely an
  out-of-the-box application

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Questions or Comments?

• Jim Holt
• jgh4_at_cdc.gov
• 770-488-5510
• BRFSS Maps
• http//apps.nccd.cdc.gov/gisbrfss/

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Visualization of County Level Data

• Planned for BRFSS Maps version 3.0 or 4.0
• Many technical and cognitive issues