1) Geographic Information Systems (GIS) allow users to visualize and analyze spatial data by linking geographical features to tabular data. 2) Pioneered in the 1960s, GIS has since become a valuable tool for epidemiology by allowing disease data to be mapped and analyzed in relation to environmental, demographic, and other spatial factors. 3) Key functions of GIS in spatial epidemiology include disease mapping, cluster detection, and risk analysis to better understand patterns and associations between disease occurrence and location.

1. Geographic Information System
– An Introduction
Dr Vinodh Kumar O.R
Division of Epidemiology
ICAR-Indian Veterinary Research Institute
Izatnagar, Bareilly-243 122

2. Dr John Snow is known as the ‘father
of modern epidemiology’ because of
the famous case of the 1854 Cholera
outbreak in London’s Broad Street
region.
Dr. John Snow
1854 Cholera outbreak in London's Broad Street region
Disease Mapping

3. Father of
Geographic Information Systems (GIS)
Roger Tomlinson
1933-2014
Canada Geographic Information System

4. GIS
+
Information System
Geography
GIS links geographical features (spatial) to tabular data (attribute)
GIS has two key activities: (1) to visualize spatial information, or “make
maps,” and (2) to analyze spatial information, or “ask questions of the maps
and data.”

5. Geographic information system
• GIS is computerized information system
that allows for the capture, storage,
manipulation, analysis, display and
reporting of geographically referenced
data.
• The geographic information is
organized in the form of various layers
or strata of thematic maps with their
related attributes.
• GIS can be used as a tool for any
discipline which handles data that can
be connected with geographical
locations, such as countries, regions,
communities, or co-ordinates
(Norstrom, 2001).

6. Methods of representing geographic
space

7. How GIS works?

8. Data structure in GIS
• Spatial data
• Vector: In vector-based
systems, geographical
features are represented
as points, arcs and
polygons.
• Raster: In grid- or raster-
based systems, spatial
information is
aggregated by
superimposing a grid
over the area of
interest; the user can
specify the dimensions
of the grid pattern.

9. Difference

10.  Epidemiology
Place (Geography)
It is estimated that over 90% of health data (animal and human) has a spatial or
geographical component .
Population
Time
 A picture is worth thousand words
 It provides insight about a disease situation and is a
value-addition
Need for Spatial Epidemiology

11. Questions to be asked in spatial epidemiology are:
 Where are the incidences located?
 What are the environmental characteristics of these
areas?
 Are there associations between incidences and the
environment at other locations?
 And, what patterns are evolving?”
(Nicol, 1991)

12. Spatial analysis … what we require?
Disease data
Time (if available date wise very good)
No of cases (no. affected)
Total population
No of deaths
Demographic Data
Species wise data
weather Data
Rainfall
Temperature
Wind speed
Wind direction
Relative humidity
Vector Data
Socio-economic Data
Land Cover and Land Use Data
Soil Data
Remote sensing data
Digital Maps – shape file
Lat Long
GIS Software
Skill and interest

13. Analysis that can be done
in spatial epidemiology
 Disease mapping
 Cluster detection
 Geographic correlation studies
 The assessment of risk in relation to a point or line-source
(predictive risk mapping)

14. 2004 2006 2007
Dotmaps Choropleth Isopleth

17. Cluster detection

18. Bhuvan portal
bhuvan.nrsc.gov.in/

19. KRISHI – ICAR Geo portal

20. EpiInfo
https://www.cdc.gov/epiinfo/index.html

21. QGIS for GIS
www.qgis.org/

22. GIS Software

23. QGIS

24. Adding shape file

25. Adding locations

26. QGIS

27. QGIS- CSV file

28. QGIS

29. Point locations