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October 2007 GIS and Census Mapping in St. Lucia
GIS AND CENSUS MAPPING IN ST. LUCIA
Presented by Sherma Lawrence
Central Statistical Office, St. Lucia
October 2007 GIS and Census Mapping in St. Lucia
Census History - Dissemination
• The previous dissemination of census results had been limited to tables and reports.
October 2007 GIS and Census Mapping in St. Lucia
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 1:2500 topographic map sheets.
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
GIS Software
• Creating multiple ED layouts within one project
October 2007 GIS and Census Mapping in St. Lucia
GIS Software• Creating dot density
map to represent population distribution at District level
October 2007 GIS and Census Mapping in St. Lucia
ArcGIS
ARC CATALOG
ARC MAP
ARC TOOLBOX(Floating Toolbar in Arc Map)
Arcview
ArcReader
October 2007 GIS and Census Mapping in St. Lucia
ArcEditor
October 2007 GIS and Census Mapping in St. Lucia
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.
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
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.
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
Creating Settlement Boundaries
• Buildings with the same address were grouped together using the select by attributes feature in Arcview
October 2007 GIS and Census Mapping in St. Lucia
October 2007 GIS and Census Mapping in St. Lucia
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 numbere.g. Sans Souci in La Borne is 120330403
Gros Islet – Monchy - La Borne - Sans Souci
12 - 033 - 04 - 03
October 2007 GIS and Census Mapping in St. Lucia
Generating Settlement Codes
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
GIS Application…..Health
October 2007 GIS and Census Mapping in St. Lucia
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
GIS Application…..Crime
October 2007 GIS and Census Mapping in St. Lucia
GIS Application…..EconomyEconomy….• Combined average income per household• Useful for poverty assessment, feasibility studies
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
GIS Application…..General Elections
October 2007 GIS and Census Mapping in St. Lucia
GIS Application…..IndustryIndustry….• Data entry of 2001 census visitation records• Classification based on the United Nations
“International Standard Industrial Classification of All Economic Activities”
NUMBERS OF BUSINESS
0
10
20
30
40
50
60
70
80
Baker
y
Man
Of C
loth
ing
Man
of F
urnitu
re
Garag
e
Mar
ket/M
inim
art/S
uperm
arke
ts
Retai
l Sto
res
Other
Ret
ail S
tore
s
Other
Non S
tore
Ret
ail
Guest H
ouse/H
otels
Resta
urant &
Bar
s
Regula
tioon o
f Public
Ser
vice
Pre/P
rimar
y
Other
Ente
rtain
men
t Act
iviti
es
Beauty
Sal
on
Type of Business
Co
un
t
October 2007 GIS and Census Mapping in St. Lucia
GIS Applications….Industry
October 2007 GIS and Census Mapping in St. Lucia
GIS Applications….Web Maps
http://www.stats.gov.lc/mapping_page/map_index.htm
October 2007 GIS and Census Mapping in St. Lucia
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
October 2007 GIS and Census Mapping in St. Lucia
The end
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