Transcript BRFSS Maps: Visualizing Oral Health Surveillance Data

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
Outline of Presentation
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Basic concepts: data tables vs. maps
Purpose and functionality of BRFSS Maps
Future enhancements to BRFSS Maps
Summary
Data Tables vs. Maps
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Different ways of looking at the data
Specific values (tables) or spatial patterns
in the data (maps)?
• In other words: “detail” vs. “simplification”
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Data for analysis (tables) or data for
visualization (maps)?
Access to ancillary information (tables)?
• Confidence intervals
• Cell sizes
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Comparison of two or more variables
What to Use: Data Table or Map?
Tooth Loss from Tooth Decay or Gum Disease, United States, 2002
Percentage of adults who reported
ever having lost more than six teeth
due to decay or gum disease
10.4 - 15.4
15.5 - 17.0
17.1 - 18.3
18.4 - 21.7
Source: Behavioral Risk Factor Surviellance System
21.8 - 33.8
Multivariate Relationships: Tables
Multivariate Relationships:
Map Comparison
Tooth Loss from Tooth Decay or Gum Disease, United States, 2002
Had Teeth Cleaned Within the Past Year, 2002
Percentage of adults who reported
ever having lost more than six teeth
due to decay or gum disease
Had teeth cleaned by a dentist or
dental hygienist within the past year
10.4 - 15.4
58.0 - 65.4
15.5 - 17.0
65.5 - 68.1
17.1 - 18.3
68.2 - 72.0
72.1 - 75.5
18.4 - 21.7
Source: Behavioral Risk Factor Surviellance System
21.8 - 33.8
Source: Behavioral Risk Factor Surviellance System
75.6 - 80.0
Multivariate Relationships:
Multivariate Map
Maps: Static vs. Interactive
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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• If data are updated - map is outdated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
BRFSS Maps
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Interactive
GIS-enabled
Internet-based mapping application
Visual depiction of BRFSS data
• States
• Metropolitan and Micropolitan Statistical
Areas (MMSA)
Purposes
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Visualization and exploratory spatial
data analysis
• Highlight regional patterns and
interstate variations
• Prompt interesting research questions
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BRFSS data in a GIS-friendly format
Encourage the use of geographicallyreferenced risk factor data
Functionality
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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
BRFSS Maps
Development Timeline
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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
Initial Map Screen
Prevalence Data
User Control over Mapping Options
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Natural breaks
Quantiles
Equal intervals
Standard deviations
Mapping by Standard Deviations
Mapping by Quintiles
Zooming and Panning
Saved Graphic Image
Download GIS Data
New Developments
Since Initial Release
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Improved internet response time in
Version 1.1
Adapted for rapid response to
emerging public health issues (e.g.,
influenza vaccination surveillance,
2004-05)
System Components
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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
System Architecture
I want to see
a map!
Web Server
HTTP request
Get
the
Send
data…
map
request
Database Server
Retrieve dataset
image streamed back
Web Browser
image streamed back
Data being mapped are
passed to GIS service
ArcIMS generates map image
GIS Server
GIS Web Service
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Mapping capability easily integrated
into existing Web sites
Increased data security
• GIS service does not require database
access
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Mapped data sent with each map request
Sensitive datasets are not exposed
Performance enhancement
• Very fast response time
• No lengthy browser downloads
BRFSS Maps
Future Enhancements
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Version 2.0
• New user interface
• Redesigned map frame
• New visualization tools
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Versions 3.0 and 4.0
• Visualization of multivariate relationships
• Visualization of county-level data
New User Interface and Map Frame
New Visualization Tools
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Natural breaks
Quantiles
Equal intervals
Standard
deviations
Manual breaks
Visualization of Multivariate
Relationships
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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
Multivariate Relationships:
Multivariate Map
Mapping County-level BRFSS Data
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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
Percentage of Adults with Fair or Poor Health,
U.S. Counties*, 1998-2001
Raw Data
*Counties with 50 or more
completed interviews, 1998-2001.
*Counties
> 50
interviews
Source: Behavioral Risk Factor Surveillance System.
Percent
2.2 - 13.1
13.2 - 15.6
15.7 - 19.0
19.1 - 24.1
24.2 - 49.6
Insufficient Data
Percentage of Adults with Fair or Poor Health,
U.S. Counties, 1998-2001
Raw Data
Note: Includes prevalence estimates for counties
with less than 50 completed interviews, 1998-2001.
All Counties
Source: Behavioral Risk Factor Surveillance System.
Percent
0.0 - 13.1
13.2 - 15.6
15.7 - 19.0
19.1 - 24.1
24.2 - 68.5
Percentage of Adults with Fair or Poor Health,
U.S. Counties, 1998-2001
Percent
Spatially-Smoothed
Note: These county-level estimates were produced through a
weighted two-dimensional median-based smoothing algorithm
("weighted headbanging"), in which the data are geographically
smoothed by adjusting each county's proportional response
based on the responses of its neighboring counties.
All Counties
Source: Behavioral Risk Factor Surveillance System.
4.3 - 13.1
13.2 - 15.6
15.7 - 19.0
19.1 - 24.1
24.2 - 41.2
Percentage of Adults with Fair or Poor Health,
U.S. Counties, 1998-2001
Percent
Isopleth Map
Note: This isopleth (contour) map is based on an inverse
distance weighted (IDW) spatial interpolation of county-level
estimates derived from a weighted two-dimensional
median-based smoothing algorithm.
Spatially-Smoothed
Source: Behavioral Risk Factor Surveillance System.
4.6 - 13.1
13.2 - 15.6
15.7 - 19.0
19.1 - 24.1
24.2 - 38.6
Cognitive Issues
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Rate retrieval and recall
Pattern recognition and recall
Map comparison
Visual dominance
User preferences
Technical Issues
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Data-related
Cartography-related
Internet-related
Summary
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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 mapping…not merely an “outof-the-box” application
Questions or Comments?
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Jim Holt
• [email protected]
• 770-488-5510
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BRFSS Maps
• http://apps.nccd.cdc.gov/gisbrfss/
Visualization of County Level Data
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Planned for BRFSS Maps version 3.0
or 4.0
Many technical and cognitive issues