Chapter 4 & 5:
GIS Database & Vector Analysis
Chapter Four: GIS Database
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What is GIS database?
• Records (formed by rows and columns)
• Descriptive information about the geographical features
• A spatial feature consists of a unique record in the
database; each distinct feature is defined by unique ID
Clicking on a building,
the detailed
information are shown
in the pop-up table
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Source: www.onemap.sg
Working with Tables – Data Type
 Field & Data Type
 Different fields will store different kind of values
 Choice of field type to match with type of data
Name
DOB
Age
Height
SocialSec
Picture
George Young
15/2/1980
32
1.70
S8067789J
D:/Picture/george.jpg
Text/String
Date
Short
Double
Text/String
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Hyperlink
Geospatial data (textual & geometry)
Attribute Data
 Spatial Data
GIS manages both spatial & attribute data

e.g. Building
Spatial
Attributes
5
Which is the common field you can link table 1 and table 2?
StaffNum
Postcode
BranchRef
Manager
Table 1
BranchRef
Branch
StaffNum
Manager
Postcode
A0023
Novena
200
Justin Bieber
478103
T0247
Clementi
182
Stefanie Sun
393910
B0021
Bedok
126
Simon Cowell
637456
Table 2
Branch Locations
StaffName
JoinDate
Dept
BranchRef
Barb Simpson
18 Dec 2002
Dairy
T0247
Randy Jackson
29 Jan 2004
Dairy
B0021
Tanya Chua
4 Sep 1998
Vegetables
T0247
***Multiple tables can be linked together based on their common keys. Table 1 and table 2 both consists of field
named BranchRef. After linking/joining both tables, you would be able to find out which staffs managed by
respective branch manager when clicking on the branch location on the map.
Ans: BranchRef
6
How many tables would you need to design if you have 3
layers (i.e Building footprints , Roads, Landlots) represented in
different form of geometries?
1 table
3 tables
2 tables
None of the above answers
***It is not possible to store different geometries within a table. In
this scenario, buildings’ layer has its own table (as do other
layers).
Ans: 3 tables
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Chapter Five: Vector Analysis
Proximity Analysis, Route Planning
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Data Analysis – Vector Data
In reality, we deal with geographical features everyday. Right at the
moment you wake up in the morning, you start to plan your
schedule of the day. You might think of going from location A to B,
then from B to C to D; what mode of transportation you will use to
reach the destinations; what is the estimated duration to reach the
destination and so on... GIS helps you to answer these sort of
questions more efficiently and visually.
 To answer the geographical-related questions, you can utilise GIS to
analyse single geographical layer or multiple layers. Firstly, you need to
understand the Spatial Relationships formed within geographical layers.
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Spatial Relationship
10
•
You can store many geographical
layers within GIS system; different
thematic layers; both vector and
raster data.
•
Each geographical layer has a
unique relationship formed with
other layers.
•
Example: Roads connects from east
to west, shopping mall 1 locates
next to post office, buildings are
located within particular town
boundary etc.
How GIS maps geographical entities in
real world?
Source: www.esri.com
Transportation
Data
Demographic
Data
Satellite Imagery
Geographical Information
System (GIS)
Terrain Data
Business Data
Health Data
Property Data
You can
integrate
many
thematic
data into
GIS
Weather Data
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You can use GIS to:
Find the high density area of residential housing
Locate potential area to set up new childcare centre
How accessible the public transportation system in
that specific area (i.e MRT, bus)
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One of the most basic questions asked of a
GIS is "what's near what?"
•
•
•
•
•
•
•
•
•
How close is this well to a landfill?
Do any roads pass within 1,000 meters of a stream?
What is the distance between two locations?
What is the nearest or farthest feature from something?
What is the distance between each feature in a layer and the features in
another layer?
What is the shortest street network route from some location to another?
How many childcare centres that are located within 1 km from my flat?
Where are the clinics, hospitals, polyclinics or 24 hrs emergency clinics from
my house?
Where is the nearest shopping malls from my office?
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Proximity Analysis (Buffer)



Create a circular region around the selected point for proximity
analysis
Search within feature or search nearby feature
Select feature from another layer
Find schools
buildingsnear
neartotoaselected
selectedprimary
buildingschool
Source: www.onemap.sg
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School Query service
Route Planning Using GIS
Transportation professionals the world over have
discovered and embraced GIS as an important tool in
managing, planning, evaluating, and maintaining
transportation systems.
For more reading:
http://www.esri.com/~/media/Files/Pdfs/library/newsletters/transportation-gistrends/summer-2012.pdf
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Examples: Road Network Analysis
•
What is the quickest way to get from Point A
to point B?
•
Which ambulances or patrol cars can
respond quickest to an incident?
•
What market areas does a business cover?
•
What are live or historical traffic conditions
like, and how do they affect my network
analysis result?
Source: www.esri.com
Using GIS to locate customer catchment
AMK Hub & NEX (5, 10 , 15 minutes service area)
Can you get your route planned via OneMap (www.onemap.sg)?
Which service on OneMap should you use to find out the list of
service bus passing through particular roads?
Answer: BusRoute Explorer
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A tourist would like to plan his/her daily tour visiting Singapore
places of interest via public transportation mode, which service
on OneMap would you suggest him/her to refer to?
Answer: Get Directions
(*you can choose mode of transportation: drive, bus or combination of Bus & MRT)
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Using OneMap, generate the cheapest route of taking bus from
Esplanade to Asian Civilisations Museum. *set 500 m for
allowable walking distance.
Q1: How much is the cheapest bus fare?
Q2: A few solutions are proposed, which solution provides the
cheapest and the fastest route to reach Asian Civilisations
Museum?
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Q1: How much is the cheapest
bus fare?
S$0.73
Q2: A few solutions are proposed,
which solution provides the
cheapest and the fastest route
to reach Asian Civilisations
Museum?
Solution 1: Total travel and
wait/walk time = appx 13
minutes
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