GIS AND CENSUS MAPPING IN ST. LUCIA

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GIS AND CENSUS MAPPING IN ST. LUCIA
Presented by Sherma Lawrence
Central Statistical Office, St. Lucia
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Census History - Dissemination

• The previous dissemination of census results had
  been limited to tables and reports.

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Census History - Maps

• In 1980 aerial photographs were used to guide the
  enumerators along their designated Enumeration
  Districts (ED).
• 1991 the aerial photographs were used in
  collaboration with hand drawn maps.
• Subdivision of island into Enumeration
  Districts (approximately 100 households per unit)
• Delineation project by Statistics Department to
  identify areas previously left out
• New EDs hand drawn to scale from 12500
  topographic map sheets.

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Introduction of GIS

• Reasons for the introduction of GIS at the
  Statistics Department
• Preparation for 2001 census
• Increasing demand for updated maps
• Technological initiatives
• Development of human and physical resources

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GIS Software

• Arcview 3.0 was chosen as the first GIS software
  package of the Statistics Department
• Simple User Interface
• Great functionality
• Upgrading from 3.0 through to 3.2

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GIS Software

• Arcview uses prior to 2001
• Digitize topographic map sheets using heads-down
  digitizing
• Subdividing of digital map in to Enumeration
  Districts using heads up digitizing

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GIS Software

• Creating multiple ED layouts within one project

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GIS Software

• Creating dot density map to represent population
  distribution at District level

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ArcGIS
Arcview
ARC MAP
ARC TOOLBOX
(Floating Toolbar in Arc Map)
ARC CATALOG
ArcReader
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ArcEditor
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Global Positioning Systems (GPS)

• Why GPS?......
• Topographical maps were out dated
• Inaccuracy in ED maps
• Rate of national development
• Need for regular updating and maintaining of
  Enumeration Districts.

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ED Development with GPS

• GPS used to update roads, footpaths and
  buildings.
• Differential correction done with pathfinder
  office
• Base files from Cable and Wireless Base Station
• New files exported as shapefiles

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Mobile GIS

• Upgrade to Trimble Geo XM GPS unit
• Functionality of a PDA with a high-tech GPS
  system
• 1-2 meter accuracy
• Microsoft Windows CE operating system
• Terrasync Software
• Arcpad software
• Import Arcview project unto the unit
• Realtime editing
• Easy transfer from desktop to mobile unit

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Updating EDs using Aerial Photos

• 2004 aerial photos obtained from the Survey and
  Mapping Section of the Ministry of Physical
  Development\
• Individual images were used because of the size
  of the file
• Inserted into Arcview as graphic
• Used as a back drop for updating EDs
• Too many trees in certain areas obstructed the
  view of houses and parts of the road
• Ground truthing field trips.

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Developing Settlements

• During the 2001 census each building was numbered
  sequentially and given a unique identifier
  comprising the 5-digit ED number and three digit
  number from 001-999.
• e.g. 14705042 would be ED number 14705 and
  building number 042

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Creating Settlement Boundaries

• Buildings with the same address were grouped
  together using the select by attributes feature
  in Arcview

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Generating Settlement Codes

• A unique 9 digit settlement code was developed
• 2 digit district code (standard)
• 3 digit main settlement number
• 2 digit sub settlement number
• 2 digit sub-sub settlement number
• e.g. Sans Souci in La Borne is 120330403
• Gros Islet Monchy - La Borne - Sans Souci
• 12 - 033 - 04 - 03

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Generating Settlement Codes
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GIS Applications

• Settlement boundaries have revolutionized the
  dissemination of census data within the
  Statistics Department.
• Statistical information can now be mapped
  relative to the administrative boundaries used by
  an agency such as Health Regions, Education
  Districts, Political Constituencies, etc

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GIS Application..Demographics

• Dot Density
• is a simple application where the value of the
  variable is represented by dots
• In the case of St. Lucia, used to represent
  population count where
• 1 dot 200 persons

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GIS Application..Demographics

• Population By Settlement ..
• It is easier to disseminate demographic
  information at the settlement level
• A Settlement map can now be provided to accompany
  the information

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GIS Application..Health

• Heath..
• Undefined boundaries
• Heath Regions were developed by combining the
  settlement catered to by the Health Centres and
  Hospitals in the Regions
• Reported case of Diabetes relative to the
  location of Health facilities by settlements

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GIS Application..Health
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GIS Application..Crime

• Crime.
• A K-mean Cluster Classification Analysis was
  performed using the results of the 2001 census to
  determine areas most prone to crime

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GIS Application..Crime
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GIS Application..Economy

• Economy.
• Combined average income per household
• Useful for poverty assessment, feasibility
  studies

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GIS Application..Elections

• General Elections..
• Redefining and re-digitizing of Electoral
  Boundaries prior to the 2001 National Elections
• Subdividing or Electoral Constituencies into
  Poling Divisions
• Providing maps for National Voter registration
  project
• Displaying Election Results on Statistics
  website http//www.stats.gov.lc/election.htm

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GIS Application..General Elections
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GIS Application..Industry

• Industry.
• Data entry of 2001 census visitation records
• Classification based on the United Nations
  International Standard Industrial Classification
  of All Economic Activities

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GIS Applications.Industry
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GIS Applications.Web Maps
http//www.stats.gov.lc/mapping_page/map_index.htm
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Conclusion

• The applications mentioned above are a mere
  demonstration of capabilities of GIS
• GIS is a valuable investment and has proven to be
  an asset at the St. Lucia Statistics Department
• GIS has positively affected the way we collect,
  analyze and use data

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• The end