Chapter 4 & 5: GIS Database & Vector Analysis

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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

Source: www.onemap.sg

Working with Tables – Data TypeField & Data TypeDifferent fields will store different kind of valuesChoice 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/StringDoubleShortDateText/String Hyperlink4

Geospatial data (textual & geometry)

e.g. Building

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Attribute Data Spatial DataGIS manages both spatial & attribute data

AttributesSpatial

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BranchRef Branch StaffNum Manager PostcodeA0023 Novena 200 Justin Bieber 478103

T0247 Clementi 182 Stefanie Sun 393910

B0021 Bedok 126 Simon Cowell 637456

Table 1

StaffName JoinDate Dept BranchRefBarb Simpson 18 Dec 2002 Dairy T0247

Randy Jackson 29 Jan 2004 Dairy B0021

Tanya Chua 4 Sep 1998 Vegetables T0247

Table 2

Which is the common field you can link table 1 and table 2?StaffNum Postcode BranchRef Manager

Ans: BranchRef

Geo-Brain Tickler 6:

***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.

Branch Locations

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Geo-Brain Tickler 7:How many tables 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

Ans: 3 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, so as other layers.

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Chapter Five: Vector AnalysisProximity Analysis, Route Planning

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Data Analysis – Vector DataIn 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 either single geographical layer or multiple layers. Firstly, you need to understand the Spatial Relationships formed within geographical layers.

Spatial Relationship

• 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

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Satellite Imagery

Weather DataTerrain Data Health DataBusiness Data

Demographic Data Property Data

Transportation Data

Geographical Information System (GIS)

You can integrate many thematic data into GIS

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You can use GIS to:Find the high density area of residential housingLocate potential area to set up new childcare centreHow 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 buildings near to selected primary schoolFind schools near to a selected building Source: www.onemap.sgSchool Query service

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Route Planning Using GISTransportation professionals the world over have discovered and embraced GIS as an important tool in managing, planning, evaluating, and maintaining transportation systems.

http://www.esri.com/~/media/Files/Pdfs/library/newsletters/transportation-gis-trends/summer-2012.pdf

For more reading:

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 catchmentAMK Hub & NEX (5, 10 , 15 minutes service area)

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Geo-Brain Tickler 8: Can you get your route planned via OneMap (www.onemap.sg)?

Which service on OneMap you will be using if you would like to find out the list of service bus passes through particular roads?

Answer: BusRoute Explorer

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Geo-Brain Tickler 9:A tourist would like to plan his/her daily tour visiting Singapore places of interest via public transportation mode, which service on OneMap you would suggest he/she to refer to?

Answer: Get Directions (*you can choose mode of transportation: drive, bus or combination of Bus & MRT)

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Geo-Brain Tickler 10: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: Few solutions are proposed, which solution provides the cheapest and the fastest route to reach Asian Civilisations Museum?

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Geo-Brain Tickler 10: Answer

Q1: How much is the cheapest bus fare?S$0.73

Q2: 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