1. Geographic Information Systems and Science
by Longley, P.A. Goodchild, M.F., Maguire, D.J. and Rhind, D.W.
Concepts & Techniques of Geographic Information Systems
by Lo and Albert K.W. Yeung
Text Books

2. Objectives
• To introduce concepts and the techniques of
handling geographical data through a particular
form of information system - GIS;
• To introduce the skills and techniques to input,
manage, analyse and display spatial
information; and
• To introduce the concepts and techniques for
spatial data analysis and modelling.

3. Outline
1. What is a GIS?
2. Representing the real world
3. GIS software
4. The nature of geographical data
5. GIS data modelling
6. Geographical databases
7. Geographical query
8. Spatial analysis
9. Digital terrain modelling
10. Network analysis
11. GIS as decision making tool
12. GIS applications

4. Graphics areGraphics are holistic:holistic:
““a picture says more than a thousand words...”a picture says more than a thousand words...”
““First road left, then crossFirst road left, then cross
the railroad and continuethe railroad and continue
until you cross the river,until you cross the river,
then the first right andthen the first right and
right again on theright again on the
crossroads...”crossroads...”
IntroductionIntroduction
Why Use GraphicsWhy Use Graphics

5. What is a GIS?What is a GIS?
A GIS is a database management system forA GIS is a database management system for
spatiallyspatially distributed features and thedistributed features and the
associated attributes.associated attributes.
• Spatial data captureSpatial data capture
• ManagementManagement
• AnalysisAnalysis
• DisplayDisplay
• Decision makingDecision making
• ResearchResearch

6. WHAT IS A GIS ?WHAT IS A GIS ?
GEOGRAPHICGEOGRAPHIC implies that locations of the data items are known, orimplies that locations of the data items are known, or
can be calculated, in terms of Geographiccan be calculated, in terms of Geographic coordinatescoordinates ((LatitudeLatitude,,
LongitudeLongitude))
INFORMATIONINFORMATION implies that the data in a GIS are organized to yieldimplies that the data in a GIS are organized to yield
useful knowledge,useful knowledge, e.ge.g
• colored maps and images,colored maps and images,
• statistical graphics,statistical graphics,
• tables, andtables, and
• various on-screen responses to interactive queriesvarious on-screen responses to interactive queries..
SYSTEMSYSTEM implies that a GIS is made up from several inter-related and linkedimplies that a GIS is made up from several inter-related and linked
components with different functions.components with different functions.
Thus, GIS have functional capabilities for data capture, input,Thus, GIS have functional capabilities for data capture, input,
manipulation, transformation, visualization, combinations, query, analysis,manipulation, transformation, visualization, combinations, query, analysis,
modelling and output.modelling and output.

7. A container of maps in digital form
A computerised tool for solving geographical problems
A mechanised inventory of geographically distributed features and
facilities
A tool for revealing what is otherwise invisible in geographical
information
A tool for performing operations on geographical data more efficiently
A spatial decision support system
Definitions of a GIS and the groups who find them useful (from
Longley, et al., 2001, pp. 10)
Some DefinitionsSome Definitions

8. •Government: where to locate public facilities (e.g. schools, hospitals and
police stations)?
•Transportation: where to build the new highway that serves most critical
bottleneck of the road network?
•Commercial: where to build new shops or good distribution centres that
make most cost effective services?
•Travellers: where am I and how can I travel from Jeddah International
Airport to Taif University?
•Country park management: where to locate ring roads in Hada that
provide the best scenery for driving at different levels with the minimum
impact on the environment?
Examples of geographical problems

9. Components of GISComponents of GIS
A working GIS systemA working GIS system
integrates these five key components:integrates these five key components:
 HardwareHardware
 SoftwareSoftware
 DataData
 PeoplePeople
 Methods/TrainingMethods/Training

10. Hardware
Hardware comprises the equipment needed to support
the many activities of GIS.
e.g. data collection and data analysis.
The central piece of equipment is the workstation, which
runs the GIS software
• Data collection requires the use of
Digitizer for conversion of hard copy data to digital data
GPS data logger to collect data in the field.
The advent of web-enabled GIS, web servers have also
become an important piece of equipment for GIS.

11. Software
• Software is essential for creating, editing
and analyzing spatial and attribute data
• e.g. Xtools, Arc View

12. Data
• Data is the core of any GIS.
• There are two primary types of data that are used in GIS.
– Geodatabase: is a database that is in some way referenced to
locations on the earth.
• Geodatabases are grouped into two different types: vector and
raster.
– Attribute data. Attribute data generally defines additional
information, which can then be tied to spatial data.

13. People
• Well-trained people knowledgeable in spatial analysis and skilled in
using GIS software are essential to the GIS process.
• There are three factors to the people component:
– education, career path, and networking.
• A person highly skilled in GIS analysis should not seek a job as a
GIS developer if they haven’t taken the necessary programming
classes.
• Finally, continuous networking with other GIS professionals is
essential for the exchange of ideas as well as a support community.

14. Training
• People working with GIS software must be
well trained how to use them.

15. BASIC FUNCTIONS OF GISBASIC FUNCTIONS OF GIS
WHAT IS IT….?WHAT IS IT….?
(LOCATIONS)(LOCATIONS)
Taif AreaTaif Area
(X,Y
)
WHERE IS IT ….?WHERE IS IT ….?
(CONDITIONS)(CONDITIONS)
WITHIN THEWITHIN THE
Subra AreaSubra Area
HOW HAS ITHOW HAS IT
CHANGED …?CHANGED …?
(TRENDS)(TRENDS)
IMPROVEMENT INIMPROVEMENT IN
GROWTHGROWTH
IN FIVE YEARSIN FIVE YEARS
WHICH DATA AREWHICH DATA ARE
RELATED ….?RELATED ….?
(PATTERNS)(PATTERNS)
NEARESTNEAREST
SafaSafa
WHAT IF….?WHAT IF….?
(MODELS)(MODELS)
FINDING SOLUTIONS TOFINDING SOLUTIONS TO
THE THIRD QUESTIONSTHE THIRD QUESTIONS

16. BASIC FUNCTIONS OF GISBASIC FUNCTIONS OF GIS
• DATA AQUISITION ANDDATA AQUISITION AND
PREPROCESSINGPREPROCESSING
DIGITIZINGDIGITIZING EDITINGEDITING
TOPOLOGY BUILDINGTOPOLOGY BUILDING
PROJECTIONPROJECTION ATTRIBUTIONATTRIBUTION

17. WHY GIS ?WHY GIS ?
• To inventory and monitor resourcesTo inventory and monitor resources
• To test the sensitivity of our analysisTo test the sensitivity of our analysis
assumptionsassumptions
• To simulate potential impacts ofTo simulate potential impacts of
management alternativesmanagement alternatives
• To make the map the 2nd time, the 50thTo make the map the 2nd time, the 50th
time, the 100th time...time, the 100th time...

18. ADVANTAGES OF GIS IN SIMPLE TERMSADVANTAGES OF GIS IN SIMPLE TERMS
• Though collection of data is difficult once it isThough collection of data is difficult once it is
collected, it can be stored safely in digital formcollected, it can be stored safely in digital form
(in computer) forever without damage, which(in computer) forever without damage, which
usually happens to our maps.usually happens to our maps.
• Once if a map is prepared accurately it can beOnce if a map is prepared accurately it can be
printed in any scale without any redrawing.printed in any scale without any redrawing.
• Large scale maps at smaller units (Beats) levelLarge scale maps at smaller units (Beats) level
can be joined for creating maps at divisions orcan be joined for creating maps at divisions or
district level, very accurately within few minutes.district level, very accurately within few minutes.
Contd..Contd..

19.  Changes can be incorporated very easily in computerChanges can be incorporated very easily in computer
and it doesn’t require any redrawing.and it doesn’t require any redrawing.
 Same map can be generated even after 100s of yearsSame map can be generated even after 100s of years
later.later.
 New things can be known after overlay of differentNew things can be known after overlay of different
themes and a new types of maps can be generated.themes and a new types of maps can be generated.
 Work can be done faster than manually.Work can be done faster than manually.
 The work of decision makers and end users willThe work of decision makers and end users will
become easier.become easier.
ADVANTAGES OF GIS IN SIMPLE TERMSADVANTAGES OF GIS IN SIMPLE TERMS

20. OriginOrigin
The Cave Paintings
1351
The Medici sea atlas is published that
contains a ‘world’ map.
1375
The Catalan atlas is prepared by
Catalan cartographers who made great
contribution in the completion of
reformation of world map.
1477
The first printed edition of the
‘Geography’, Bologna is published on
the basis of manuscript atlases,
produced by Dominus Nicholaus
Germanus
Cave Paintings are considered to be the first GIS Maps as
some unknown information (attributes) is linked to it.
A. Cave Paintings have graphic information
regarding the animals and their tracks of
migration.
B. These paintings used to get shared with in
the tribe groups through generations.
C. Most of the ancient civilizations are found by
its Cave Paintings.
1.Mesapotomia
2.Central Asia

21. Manual MappingManual Mapping
Manual Mapping
Dr.John Snow in 1854 used London City Map to Depict
Cholera effected areas.
•Dr.John snow has used a manual Map to track the
cholera effected area of the central London, which
has been ultimately resulted in finding a
contaminated well. This is considered as the first GIS
analysis in the world.
•Europeans produced first Manual Maps to travel
over seas.(Vascodigama,Columbus).
• In American Rervolution Maps are used with huge
Overlays to track the Troop Movements.
Manual Mapping is an art of
showing the real time objects
on a piece of paper with a uniq
concept located in it.
(geography,History,social
changes)

22. CAD (Computer Aided Drafting)CAD (Computer Aided Drafting)
CAD is rooted in drafting—CAD has a great facility for creating and representing geographic features
as drawings in a computer
In early graphics systems, the data model was simple and
consisted almost entirely of symbolized graphic features
Advantages:
• Features were represented by a graphic symbol
• Features were stored in a single file format.
•Tracking of the data was much easier.
In graphic system software, map files (i.e., layers) can be
edited, manipulated, displayed, & generally managed..
Disadvantages:
• Features were not so intelligent as today.
• The time taken to regenerate the drawing is very high.
• Performance of the system is very poor due to graphic size.
• Editing of the existing drawing/Map is is very hectic as if
one feature is effected in one area then all the feature with
the same symbol need to be changed again.

23. AM/FM a Semi GISAM/FM a Semi GIS
After 1970’s CAD have been implemented in many sectors and was very
successful.
However, Large Utility companies and other companies which needed
Facility Mapping suffered with the inabilities of CAD systems.
The Concept of facility Mapping has been into the lime lite around mid 70’s.
FM is nothing but CAD but it has its own defined features in it (transformers,
repeaters) along with the default text. Some advanced FM systems even
provided a data linking facility to the features.
In one word an AM/FM systems is 90% Automated CAD systems with its
defined features.
Later on FM has become the stepping stone for GIS

24.  1988 - Indian Remote Sensing Satellite (IRS) system is commissioned with
the launch of IRS-1A.
 1989 - The National Remote Sensing Agency prepares the first Wasteland
Atlas.
 1989 - The National Remote Sensing Agency prepares the first Wasteland
Atlas.
 1996
-ESRI India is formed.
- Tata Consultancy Services (TCS), India established in 1968, starts with the
TCS GIS group to provide services in the areas of GIS, Digital Image
Processing, Automated Mapping and Facility Management.
-The Mountain Natural Resource Information Systems (MENRIS),Nepal is
established to facilitate the application of GIS and remote sensing
( contd…)
Mile Stones in GIS

25.  1998
- Tata Infotech is appointed as exclusive distributor of MapInfo products in
SAARC region.
- Bentley India is established.
- Kampsax India Ltd. a photogrammetry is formed.
- Tele Atlas starts its operation in India.
1999
-The first "GIS Forum South Asia’99" is organised at Nepal.
- Autodesk India Ltd. is formed.
- Landsat 7 carrying Enhanced Thematic Mapper Plus (ETM+) is launched.
- IKONOS is launched
Mile Stones in GIS

26. TrendsTrends
Era of Manual Mapping
AMFMGIS
Desktop GIS
Application GIS
CADCAM
Web GIS Mobile GIS
MapObjects
MapX
GeoPbjects
Internet GIS
ArcIMS
MapXtreame
WebMap
MapGuide
Handheld GIS
ArcPAd
MapInfo
SuperGIS
Server Based GIS

27. Implementing GIS in various DomainsImplementing GIS in various Domains
 UtilitiesUtilities
 Transport & logisticsTransport & logistics
 CommunicationCommunication
 Urban planningUrban planning
 MilitaryMilitary
 ForestryForestry
 EnvironmentEnvironment
 AgricultureAgriculture
List Of some important DomainsList Of some important Domains

28. What Data is in Your GIS?What Data is in Your GIS?
• WhatWhat featuresfeatures do you map?do you map?
• WhatWhat attributesattributes do you need to collectdo you need to collect
data on?data on?
• WhatWhat attribute valuesattribute values can you give thecan you give the
attribute?attribute?

29. GIS Topology
Node Line (Arc) Area(polygon)
Basic Elements

30. GIS Topology

31. Point FeaturesPoint Features
• Points have a single geographicPoints have a single geographic
coordinate such as:coordinate such as:
– TreeTree
– Traffic accidentTraffic accident
– Lamp postLamp post

32. Line FeaturesLine Features
• Lines (Arcs) are a series of geographicLines (Arcs) are a series of geographic
coordinates joined to form a line suchcoordinates joined to form a line such
as:as:
– RoadRoad
– StreamStream
– RailwayRailway

33. Area FeaturesArea Features
• Areas (Polygons) are a series ofAreas (Polygons) are a series of
geographic coordinates joined togethergeographic coordinates joined together
to form a boundary such as:to form a boundary such as:
– LakeLake
– Soil typesSoil types

34. Geography Data Types and Data
Models
Map data. (SPATIAL) Map data contains the location
and shape of geographic features. (CartographicCartographic (Map(Map
Data)Data))
Attribute data. Attribute (tabular) data is the descriptive
data that GIS links to map features.
Image data. Image data ranges from satellite images
and aerial photographs to scanned maps (maps that
have been converted from printed to digital format).

35. Data models for GIS
(Spatial Data)
Spatial Data refers to information related to a
location anywhere on the earth's surface, and allows
users to look at an area or geographic feature in
relation to other areas (in relation to changes over
time and in relation to various factors)

36. Data models for GIS
(Spatial Data)
SPATIAL DATASPATIAL DATA
Vector (Object-Based)
Raster (Field-Based)

37. Object-based model (vector)
Geographic space is populated by
discrete and identifiable objects

38. Discrete Data
Data that can only take certain values.
For example: the number of students in a class
(you can't have half a student).

39. Continuous Data
Data that can take any value (within a range)
Examples: heights. People's heights could be
any value (within the range of human heights),
not just certain fixed heights.

40. A discrete object
• Has identifiable boundaries
• Is relevant to some intended application
• Is describable by one of more attributes
(characteristics)

41. Objects
• Exact objects - are generally man-
made features with precise boundaries
(e.g. buildings, bridges, etc.)
• Inexact objects - are generally natural
features with transitional, or “fuzzy”
boundaries. (rivers, trees, etc.)

42. Objects are represented as:
• Points
• Lines
• Polygons

43. Vector Data StructuresVector Data Structures
Vector data files has been captures asVector data files has been captures as
points, lines and polygonspoints, lines and polygons- Land cover- Land cover
classes is a fine example.classes is a fine example.

44. Field-based model (raster)
Geographic space is populated by one
or more spatial phenomena

45. Spatial phenomena
Are real-world features that vary
continuously over space with no obvious
or specific extent and are represented as
surfaces

46. The surfaces in a field-based model
can be conceptualized as being
composed of:
• Grid cells or pixels
– regular tessellations
• Polygons (i.e., triangles)
– irregular tessellations
RASTER MODELRASTER MODEL

47. Spatial data structuresSpatial data structures
Raster data files consists of rows ofRaster data files consists of rows of
uniform cells coded according to datauniform cells coded according to data
vvalues- Land cover classes is a finealues- Land cover classes is a fine
example.example.

48. ADVANTAGES OF VECTOR MODELADVANTAGES OF VECTOR MODEL
• PRECISE EXPRESSIONPRECISE EXPRESSION
• LESS DATA VOLUMELESS DATA VOLUME
• FAST RETRIEVALFAST RETRIEVAL
• FAST CONVERSIONFAST CONVERSION
ADVANTAGES OF RASTER MODELADVANTAGES OF RASTER MODEL
• SIMPLE DATA STRUCTURESIMPLE DATA STRUCTURE
• EASY FOR MODELLINGEASY FOR MODELLING
• SUITABLE FOR 3D DISPLAYSUITABLE FOR 3D DISPLAY
• INTEGRATION OF IMAGE DATAINTEGRATION OF IMAGE DATA
• AUTOMATED DATA CAPTUREAUTOMATED DATA CAPTURE
DISADVANTAGES OF VECTOR MODELDISADVANTAGES OF VECTOR MODEL
• COMPLICATED STRUCTURECOMPLICATED STRUCTURE
• DIFFICULTY IN UPDATINGDIFFICULTY IN UPDATING
• EXPENSIVE DATA CAPTUREEXPENSIVE DATA CAPTURE
DISADVANTAGES OF RASTER MODELDISADVANTAGES OF RASTER MODEL
• LARGE DATA VOLUMELARGE DATA VOLUME
• LOW PRECISIONLOW PRECISION
• DIFFICULTY IN NETWORKDIFFICULTY IN NETWORK
ANAYLYSISANAYLYSIS
• SLOW CONVERSIONSLOW CONVERSION

49. Attribute Data ModelAttribute Data Model
• Non-Cartographic (Attribute)Non-Cartographic (Attribute)--
descriptive information in a databasedescriptive information in a database
about the cartographic features locatedabout the cartographic features located
on a map.on a map.
– AttributesAttributes
– Attribute ValuesAttribute Values

50. Tabular ModelTabular Model
Hierarchical ModelHierarchical Model
Relational ModelRelational Model
Network ModelNetwork Model
Object-Oriented ModelObject-Oriented Model
Attribute Model TypesAttribute Model Types

51. AttributesAttributes can be numeric or alfa numericcan be numeric or alfa numeric
data that is assigned to a point, line or areadata that is assigned to a point, line or area
spatial featuresspatial features
Example Attributes…Example Attributes…
Stand ID, Compartment no,VegetationStand ID, Compartment no,Vegetation
type, Name of the Forest Block,Type oftype, Name of the Forest Block,Type of
Road,VSS code etc.,Road,VSS code etc.,
AttributesAttributes

52. AttributesAttributes
Description or characteristic of a featureDescription or characteristic of a feature
• Possible attributes for the feature TreePossible attributes for the feature Tree
– HeightHeight
– DiameterDiameter
– SpeciesSpecies
– ConditionCondition
– AgeAge

53. Attribute ValuesAttribute Values
The value given to an attributeThe value given to an attribute
• PossiblePossible valuesvalues for the attributes of afor the attributes of a
Tree featureTree feature
– HeightHeight = 15m= 15m
– DiameterDiameter = 0.75m= 0.75m
– SpeciesSpecies = Oak= Oak
– ConditionCondition = Good= Good
– AgeAge = 8 years= 8 years

54. Types of Attribute ValuesTypes of Attribute Values
There are a number of different types ofThere are a number of different types of
attribute valuesattribute values
Feature Attribute Attribute Values
Character Pole Pole ID ABC123
Numeric Pole Height 15m
Menu Pole Condition Good
Average
Poor
Date Pole Date User generated
Auto generated
Time Pole Time User generated
Auto generated

55. Data Quality
• “fitness for use”
• varies with
– intended use
– scale
– method of collection

56. Measures of data quality
• reliability
• accuracy
• relevance
• timeliness
• intelligibility
• completeness
• known precision
• concise
• convenience
• integrity

57. More considerations
• projection
• scale
• classification scheme
• cartographic quality
• metadata
• transfer format

58. Accuracy
• how closely the data represent the real
world
• limited by
– data collection equipment and technique
– intended use
– cost

59. Precision
• exactness of representation
• numerical data
– number of significant digits
• categorical data
– level of detail
– number of categories

60. Error
• deviation, variation, & discrepancy
• lack of accuracy & precision
• types
– systematic
– random

61. Error Sources
• original source material
• data collection
• data automation and compilation
• data processing and analysis
• inherent & operational

62. Uncertainty
• degree of doubt
• accuracy and precision are not known
• error is not known (but may be large)
• greater when data from multiple sources &
scales are mixed

63. Components of data quality
• lineage (data history)
• positional accuracy
– “one line width”
– varies with scale
– tables
• attribute accuracy
– numerical
– categorical

64. Components of data quality
• logical consistency
– with real world
– within model & system
– between data sets & files
• boundary errors
• layering errors
• completeness
– spatial
– thematic

65. Components of data quality
• temporal accuracy
– precision of temporal measurements
– age of data
• semantic accuracy
– labeling

66. Assessment of data quality
• positional accuracy
– random sample
– root mean square
error (RMSE)
– examine results for
patterns &
concentrations
• attribute accuracy
– random sample
– error matrix
– errors of inclusion &
exclusion
– percent correctly
classified

67. Data Capture SourcesData Capture Sources
• Digitizing from paper mapsDigitizing from paper maps
• ScanningScanning
• Traditional surveying techniquesTraditional surveying techniques
• Paper records & field notesPaper records & field notes
• PhotogrammetryPhotogrammetry
• Remote sensingRemote sensing
• GPSGPS

68. GIS Data StorageGIS Data Storage
• CartographicCartographic (Map Data)- observations on(Map Data)- observations on
spatially distributed features, activities, orspatially distributed features, activities, or
events, which are definable as:events, which are definable as:
– PointsPoints
– Lines (Arcs)Lines (Arcs)
– Areas (Polygons)Areas (Polygons)

69. GIS Data StorageGIS Data Storage
• Non-Cartographic (Attribute)Non-Cartographic (Attribute)--
descriptive information in a databasedescriptive information in a database
about the cartographic features locatedabout the cartographic features located
on a map.on a map.
– AttributesAttributes
– Attribute ValuesAttribute Values