Introduction to GIS

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					 Introduction to Geographical
  Information Systems (GIS).
• For a number of reasons, GIS is more difficult to
  define than might at first be imagined. Although
  there has been some debate about the origin of
  the term and the date of initiation of work in the
  field, it is clear that GIS are relatively recent
  phenomena. Throughout the last 35 years there
  has been a rapid rate of theoretical, technological
  and organizational development in the GIS field,
  culminating in a period of intense activity in the
  last 10 years or so. The recent origin and rapid
  rate of progress has not been conducive to the
  analysis and definition of GIS.
                                                    1
INTRODUCTION TO GIS CONTD.
• The commercial orientation of much GIS activity
  has led to a great deal of rhetoric. There has
  been a mushrooming of new computer systems
  which purport (pretend to be intended) to be GIS,
  many of which are existing system re-packaged
  and re-labeled in an attempt to exploit market
  opportunities. Associated with this has been a
  rise in the number of GIS consultants, many of
  whom appear to offer conflicting advice and
  information regarding GIS. Any discipline or
  concept, which is in widespread use by a
  heterogeneous group of users, is almost certain
                                                   2
  to be difficult to define.
INTRODUCTION TO GIS CONTD.
• The GIS field is further characterized by a
  great diversity of applications. GIS are
  integrating systems which bring together
  ideas developed in many areas including the
  fields of agriculture, botany, computing,
  economics, mathematics, surveying, geology,
  hydrology, environmental sciences and, of
  course, Geography. Inevitably, it is difficult to
  distinguish between the competing claims of
  different organizations and individuals, all of
  which wish to be represented in a vibrant and
  profitable sector.                                3
INTRODUCTION TO GIS CONTD.
• It is also difficult to define GIS because there
  are many different ways of defining and
  classifying objects and subjects. Not
  surprising, given the diversity of the field,
  many different methods have been applied to
  defining GIS. The main reason for definitional
  difficulties stems from genuine academic
  debate about the central focus of current GIS
  activity. Some people believe that hardware
  and software are the central focus, others
  argue that the key element is information
  processing or even applications.                 4
INTRODUCTION TO GIS CONTD.
• GIS are seen by many as special cases of
  information systems in general. Information is
  derived from the interpretation of data, which are
  symbolic representations of features. The value
  of information depends upon many things
  including its timeliness, the context in which it is
  applied and the cost of collection, storage,
  manipulation and presentation. Information is
  now a valuable asset, a commodity that can be
  bought and sold for a high price. Information and
  its communication are one of the key
  development processes and characteristics of
                                                       5
  contemporary societies.
HISTORY AND DEVELOPMENT
         OF GIS
• GIS is a relatively new science (art?) and has
  developed through a number of well-defined steps,
  normally paralleling computer technological
  development. This section is tackled by considering
  the statement that "…the pattern of GIS development
  since 1965 has been largely attributable to the
  changing balance between the costs of hard-ware,
  communications and soft-ware development".




                                                    6
    Pioneer/Research Frontier
              Period:
•   1950's - 1975 in USA and UK.
•   Strength of individuals, limited
    international links, little data.
•   Ambition greater than technological
    capability.



                                          7
  Formal Experimental and
Government-funded Research
• 1973 - early 1980's
• Role of individual diminished at
  international level, still strong at local
  level eg. head of mapping agencies.




                                               8
       Commercial Phase:

•   ca. 1982
•   Strong competition between vendors -
    gives way to fourth phase of:-




                                           9
User Dominance and Control:

•   Seen as the "end of the beginning for GIS".
•   A vital characteristic of both the latter
    phases is that these activities became
    routine: in earlier phases, skilled people
    were required to be on hand to cope with
    problems in the software, data or hardware.


                                              10
 HISTORY AND DEVELOPMENT
          CONTD.
• GIS developments, other than in the United States, where more
  limited until late in the 1980s, although Japan, the United
  Kingdom and several other countries in mainland Europe are in
  rapid evolution and have well developed GIS systems in place.
  The developed perception by informed decision makers of the
  need for spatial data and solutions has led potential users to
  seek GIS solutions and has encouraged commercial providers
  to develop and offer systems to convert that perceived need into
  a reality.
• What is not so clear from the evidence, however, is the ratio of
  failures to successes or how many operational systems are fully
  used and living up to their promises.




                                                                 11
              South Africa:
• GIS interest in South Africa first manifested
  itself approximately 10-15 years ago. Yet only
  in the last 8-10 years has there been
  significant progress in this field. Interest in
  technology dealing with the processing of
  geo-referenced data has been present in
  South Africa for many years, but this has
  been concentrated in Image Processing
  methods and technologies. The actual
  impetus for GIS investigation can be traced to
  a number of institutions around the country.
                                                12
         GIS IN SA. CONTD.
• More accurately, it could be traced to the
  initiatives of a number of individuals in those
  institutes. Of these, the ones that come to
  mind are the Directorate of Surveys and
  Mapping, Environmental Affairs,
  Development and Aid, Geological Surveys
  and City Councils such as Cape Town and
  Johannesburg. The later two organizations
  were some of the first organizations to realize
  the potential of computer systems for
  capturing and processing land or parcel
  related data.                                   13
        GIS IN SA. CONTD.
• Automated mapping never seems to have
  played any significant role in the South
  African context. More prominent were the
  Computer Aided Design (CAD) applications
  that were introduced to major organizations
  such as ESKOM and numerous other
  institutions involved in some form of graphic
  input and output. This might or might not
  have had a geographical context.
                                                  14
           GIS IN SA. CONTD.
• Since the early 1980s, many more organizations have
  shown interest in acquiring information systems that deal
  with the management of geo-referenced data. For
  example the Surveyor General is implementing a Land
  Information System which concentrates primarily on
  managing parcels of land. The same applies to many city
  and town councils. However, the so-called GIS tools in
  certain institutions are not true GIS. In many cases they
  are interactive graphic systems capable of interfacing with
  database management systems, but not necessarily able
  to process all aspects of geo-referenced data such as
  projections or spatial analysis. In other instances the
  technology caters for the full spectrum of GIS functionality,
  but they are underutilized.
                                                             15
         GIS IN SA. CONTD.
• There are certain logical reasons for this:
• The organization in question does not require full
  GIS functionality,
• The technology being used is out of date and
  does not have the capabilities of a fully-fledged
  geo-referenced system,
• The purchase of the system was technologically
  driven rather than application centered,
• The users have not yet fully recognized the
  benefits of a GIS to the organization as a whole.
                                                   16
       GIS IN SA. CONTD.
• Organizations that deal with resource
  management seem to be more acutely
  aware of the synthesizing and
  management capabilities of GIS.
  Furthermore, successful implementation
  requires support from the top-
  management and a thorough Needs
  Assessment study before developing
  GIS capabilities.
                                       17
        GIS IN SA. CONTD.
• The above outline is only intended to
  give an idea of the status of GIS in
  South Africa. The potential of the South
  African market is vast, but exploitation
  thereof is still in its infancy. There are
  major difficulties facing the South
  African user, namely;

                                           18
          GIS IN SA. CONTD.
• Little educational infrastructure to train both users
  and maintainers of GIS systems. Presently the
  expertise resides mainly in the organizations that
  have initiated interest, and in the vendors which sell
  the systems. For the most part, knowledge has been
  gained through personal experience.
• Because of the above the user base is ill informed,
  often misguided by vendor's interests or by personal
  biases
• The potential of GIS is typical first perceived by the
  application user, who is generally not at managerial
  level. Convincing management of advantages of the
  technology can be a difficult task.                    19
          GIS IN SA. CONTD.
• Further factors of resistance to change,
  misunderstanding or ignorance of the technology and
  lack of funds available also restricts the potential of
  users at research level.
• Due to lack of experience amongst some users,
  those who have purchased systems have often highly
  underestimated the financial and human resources
  required implementing and maintaining these
  systems.
• The availability of data in digital form can hamper
  certain potential users. The cost of capturing base
  data is often to high for a single institution to bear,
  making it difficult to justify investment in this       20
  technology.
       THE TECHNOLOGICAL
       ENVIRONMENT OF GIS
• Issue of GIS vs CAD vs DBMS
• Often argued that GIS is a sub-set of CAD, DBMS,
  computer cartography and remote sensing.
• CAD = design and drafting of new objects, graphic
  based, uses symbols, rudimentary links to a
  database, small quantities of data used. Very limited
  analytical capabilities.
• Computer Cartography = focus on data retrieval,
  classification and automatic symbolization. Emphasis
  display over analysis and high quality output.
• DBMS = well-developed for storing/retrieving non-
  graphic attribute data. Limited graphical ability.
  Simple analytical functions.                          21
   TECHNICAL ENVIRONMENT
           CONTD.
• Remote Sensing = Collect, manipulate and
  display raster data, typically derived from
  scanners mounted on aircraft/satellites.
• All above systems pre-date GIS. Advantage of
  GIS is that it has all these above capabilities
  PLUS a greater emphasis and ability to perform
  analytical operations.
• Are three distinct but overlapping views: the map,
  the database and spatial analysis.
• Not in conflict with each other. A single system is
  viewed in all three ways depending on
  perspective of user/application.                   22
  TECHNICAL ENVIRONMENT
          CONTD.
• The relationship between GIS and
  computer-aided design, computer
  cartography, database management
  and remote sensing information system
  is important as it is sometimes argued
  that GIS is a subset of these systems


                                       23
  TECHNICAL ENVIRONMENT
          CONTD.
• Computer aided design (CAD) systems were
  developed for designing and drafting new
  objects. They are graphic based and use
  symbols as primitives to represent features in
  the interactive design process. CAD systems
  have only rudimentary links to databases that
  typically might contain part listings of stock
  reference numbers. They use only simple
  topological relationships and, on the whole,
  deal with relatively small quantities of data.
  CAD systems have limited analytical
  capabilities.                                  24
  TECHNICAL ENVIRONMENT
          CONTD.
• Computer cartography systems focus on data
  retrieval, classification and automatic
  symbolization. They emphasize display rather
  than retrieval and analysis. Computer
  cartography systems utilize simple data
  structures that lack information on topology.
  They can be linked to a database
  management system but only simple retrieval
  operations are normally undertaken.
  Computer cartography systems usually have
  many facilities for designing maps and
  producing high quality output in vector format.
                                                25
  TECHNICAL ENVIRONMENT
          CONTD.
• Database management systems (DBMS) are
  well-developed software systems optimized
  for storing and retrieving non-graphic attribute
  data. They have limited graphical retrieval
  and display capabilities. DBMS are designed
  for the short-term retrieval and update of
  relatively small quantities of data and lack
  anything other than simple analytical
  functions. They have limited capabilities for
  implementing spatial analytical operations
                                                 26
  TECHNICAL ENVIRONMENT
          CONTD.
• With the enhancement of digital
  cartographic capabilities, links were
  added to the rapidly expanding
  database technology. The use of DBMS
  is very important to the current concept
  of GIS, which involves the integrating of
  both attribute and spatial data.

                                          27
  TECHNICAL ENVIRONMENT
          CONTD.
• These systems all predate GIS, which,
  because they have evolved from them,
  have many features in common. GIS,
  however, have a number of other
  features not available in other systems.
  The major characteristic of GIS is the
  emphasis placed on analytical
  operations.
                                             28
   TECHNICAL ENVIRONMENT
           CONTD.
• More recently developments in GIS have been a part
  of the wider revolution in information management.
  GIS is no longer a stand-alone system, but is
  becoming an increasingly integral part of the digital
  desktop. A key skill of the GIS specialist today is the
  management of Geographical Information across a
  range of integrated information systems, including
  decision support systems and executive support
  systems (EIS). Information is power and its
  successful management is critical to most
  organizations. Further technical advances, such as
  multimedia, can also enhance information
  management, particularly in the areas of image-
                                                          29
  based systems.
  TECHNICAL ENVIRONMENT
          CONTD.
• Multimedia facilities allow the integration of
  text, graphics, images (static and moving)
  and sound into one single system. As a
  consequence, communication and
  visualization of information are playing an
  increasingly important role in GIS. The
  Internet is also increasingly playing an
  important role in information systems. In GIS,
  a number of products are on the market that
  enables interactive GIS across the Internet.
                                               30
THREE STAGE DEVELOPMENT
         OF GIS
1. Orientated towards data collection and
   inventory operations.
2. After 3-5 years emphasis shifts to
   analytical operations.
3. Maturity after another 5 years - true
   decision support systems, spatial
   analysis and modeling operations are
   routinely performed.

                                        31
         Three Views of GIS

• The various ideas about GIS can be synthesized
  and presented in the form of 3 distinct but
  overlapping views. The map focuses on
  cartographic aspects of GIS. Supporters of this
  view see GIS as map processing or display
  systems. In map processing each data set is
  represented as a map (also called a layer, theme
  or coverage). The output of these operations is
  another map. The database view of GIS
  emphasizes the importance of a well-designed
  and implemented database. A sophisticated
  database management system is seen as an
                                                  32
  integral part of a GIS.
     THREE VIEWS CONTD.
• This view predominates among members of
  the GIS community who have a computer
  science background. The third view of GIS
  emphasizes the importance of spatial
  analysis. This view focuses on analysis and
  modeling in which GIS is seen more as a
  spatial information science than a technology.
  This view looks likely to become the most
  widely accepted by the GIS community and
  already it can be used to differentiate
  between GIS and other information systems.
                                               33
     THREE VIEWS CONTD
• Although these views of GIS are widely held,
  few people see them as conflicting. A single
  system may be viewed in all three ways
  depending on the perspective of the user or
  the application in hand. Nevertheless, this
  classification system serves a useful function
  in highlighting the ways in which GIS are
  used by the GIS community. It also illustrates
  once again the widespread applicability of
  GIS and the heterogeneity of the GIS
                                               34
      COMPONENTS OF GIS
• To some, GIS means only the suite of software
  used to analyse geographically referenced data.
  To others the term includes the hardware utilized
  by the system. Yet others would include all
  processes from data acquisition to data
  presentation. One recent definition reads "… a
  system for capturing, storing, checking,
  integrating, manipulating, analysing and
  displaying data which are spatially referenced to
  the Earth" This is normally considered to include
  a spatially referenced computer database and
  appropriate applications software.
                                                  35
COMPONENTS OF GIS CONTD.
FROM THE VARIOUS DEFINITIONS OF GIS IT CAN BE DEDUCED
THAT GIS CANNOT EXIST WITHOUT SOME BASIC COMPONENTS.
THESE ARE PEOPLE, DATA, HARDWARE, SOFTWARE AND
PROCEDURES.

PEOPLE: THIS IS THE MOST IMPORTANT COMPONENT IN A GIS.
PEOPLE MUST DEVELOP THE PROCEDURES AND DEFINE THE
TASKS OF THE GIS. PEOPLE CAN OFTEN OVERCOME SHORTFALLS
IN OTHER COMPONENTS OF THE GIS, BUT THE OPPOSITE IS NOT
NECESSARILY TRUE. THE BEST SOFTWARE AND COMPUTERS
CANNOT COMPENSATE FOR INCOMPETENCE.

DATA: THE AVAILABILITY AND ACCURACY OF DATA CAN
AFFECT THE RESULTS OF ANY QUERY OR ANALYSIS.




                                                        36
   COMPONENTS CONTD.
HARDWARE: HARDWARE CAPABILITIES AFFECT
PROCESSING SPEED, EASE OF USE AND TYPE OF OUTPUT
AVAILABLE. ALSO CERTAIN SOFTWARES REQUIRE
SPECIFIC NEEDS FROM THE HARDWARE.

SOFTWARE: THIS INCLUDES NOT ONLY THE ACTUAL GIS
SOFTWARE, BUT ALSO VARIOUS DATABASE, DRAWING,
STASTICAL, IMAGING OR OTHER SOFTWARE.

PROCEDURES: ANALYSIS REQUIRES WELL DEFINED,
CONSISTENT METHODS TO PRODUCE CORRECT AND
REPRODUCIBLE RESULTS




                                                   37
      FUNCTIONS OF GIS
ANY GIS SHOULD BE CAPABLE OF AT LEAST THE
FOLLOWING FUNDAMENTAL OPERATIONS IN ORDER TO BE
USEFUL FOR FINDING SOLUTIONS TO REAL-WORLD
PROBLEMS.

CAPTURING DATA: A GIS MUST PROVIDE METHODS FOR
INPUTTING GEOGRAPHIC(COORDINATE) AND
TABULAR(ATTRIBUTE) DATA. THE MORE INPUT METHODS
AVAILABLE, THE MORE VERSATILE THE GIS.

STORING DATA: THERE ARE TWO BASIC DATA MODELS
FOR GEOGRAPHIC(SPATIAL) DATA STORAGE, VECTOR AND
RASTER. ATTRIBUTE DATA IS MANAGED VIA DATABASE
MANAGEMENT MODELS EG, THE RELATIONAL DATABASE.


                                               38
      FUNCTIONS CONTD.
QUERYING DATA: A GIS MUST PROVIDE UTILITIES FOR FINDING
SPECIFIC FEATURES BASED ON THEIR LOCATIONS OR ATTRIBUTE
VALUES.

ANALYZING DATA: A GIS MUST HAVE THE ABILITY TO ANSWER
QUESTIONS REGARDING THE INTERACTION OF SPATIAL
RELATIONSHIPS BETWEEN MULTIPLE DATA SETS.

DISPLAYING DATA: THERE MUST BE TOOLS FOR VISUALISING
THE GEOGRAPHIC FEATURES USING A VARIETY OF SYMBOLOGY.

OUTPUT: RESULTS OF DISPLAY SHOULD BE ABLE TO BE OUTPUT
IN A VARIETY OF FORMS, SUCH AS MAPS, REPORTS AND GRAPHS,
EVEN IN DIGITAL FORM EG. CDS.




                                                        39
 Selected Definitions of GIS:

• Department of the Environment (1987): "… a system
  for capturing, storing, checking, manipulating,
  analysing and displaying data which are spatially
  referenced to the Earth".
• Aronoff (1989): "… any manual or computer based
  set of procedures used to store and manipulate
  geographically referenced data".
• Carter (1989): "… an institutional entity, reflecting an
  organizational structure that integrates technology
  with a database, expertise and continuing financial
  support over time".
• Parker (1988): "… an information technology which
  stores, analyses and displays both spatial and non- 40
  spatial data".
        DEFINITIONS CONTD.
• Dueker (1979): "… a special case of information systems where
  the database consists of observations on spatially distributed
  features, activities or events, which are definable in space as
  points, lines or areas. A GIS manipulates data about these
  points, lines and areas to retrieve data for ad hoc queries and
  analysis".
• Smith et al (1987): "… a database system in which most of the
  data are spatially indexed, and upon which a set of procedures
  operated in order to answer queries about spatial entities in the
  database."
• Ozemoy et al (1981): "… an automated set of functions that
  provides professionals with advanced capabilities for the
  storage, retrieval, manipulation and display of geographically
  located data".

                                                                  41
      DEFINITIONS CONTD.
• Burrough (1986): "… a powerful set of tools
  for collecting, storing, retrieving at will,
  transforming and displaying spatial data from
  the real world".
• Cowen (1988): "… a decision support system
  involving the integration of spatially
  referenced data in a problem-solving
  environment".
• Devine & Field (1986): "… a form of MIS
  [Management Information System] that allows
  map display of the general information".     42
      DEFINITIONS CONTD.
• Many of the definitions above are relatively
  general and cover a wide range of subjects
  and activities. All of the definitions, however,
  have a single common feature, namely that
  GIS are systems that deal with geographical
  information. In GIS, reality is represented as a
  series of geographical features defined
  according to two data elements. The
  geographical (also called locational) data
  element is used to provide a reference for the
  attribute (also called statistical or non-
  locational) data element.                        43
      DEFINITIONS CONTD.
• For example; administrative boundaries, river
  networks and point locations of hill tops are
  all geographical features used to provide a
  reference for, respectively, census counts,
  river water flows or site elevations. In GIS, the
  geographical element is seen as more
  important than the attribute element and this
  is one of the key features, which differentiates
  GIS from other information systems.
                                                 44
      DEFINITIONS CONTD.
• Taylor (1991) points out that there is no
  universally accepted definition of a GIS and the
  terminology in the field includes a number of
  closely related terms such as land information
  system (LIS), land and resource information
  system (LRIS), urban information system (URIS),
  environmental information system (ERIS) and
  cadastral information system (CAIS). All of these
  deal with geographical and spatial data of various
  types and at various scales, which seem to be
  the two major factors influencing the terminology
  used.
                                                  45
      DEFINITIONS CONTD.
• Most importantly GIS is an information system. A
  system is a group of connected entities and
  activities that interact for a common purpose. An
  information system is a set of processes,
  executed on raw data, to produce information
  that will be useful in decision-making. It requires
  a chain of events which leads to observations
  and collection of data through analysis.
  Furthermore, an information system must have a
  full range of functions to handle observation,
  measurement, description, explanation,
  forecasting and decision making
                                                    46
WORKING DEFINITION OF GIS

A COMPUTER-BASED TECHNOLOGY
AND METHODOLGY FOR
COLLECTING, MANAGING,
ANALYZING, MODELLING AND
PRESENTING GEOGRAPHIC DATA
FOR A WIDE RANGE OF
APPLICATIONS. (DAVIS, 2001)

                              47
      PLANNING PHASES
     THE PROCESS OF ENVIRONMENTAL AND
     NATURAL-RESOURCES PLANNING AND
     MANAGEMENT MAY BE DIVIDED INTO FOUR
     PHASES.
1.   AWARENESS AND ORGANIZATION:
     THE RECOGNITION THAT A PROBLEM EXISTS
     AND THAT DETAILED STUDIES BASED ON
     SPECIFIC OBJECTIVES WILL BE REQUIRED FOR
     SUCCESSFUL PLANNING.
2.   INVENTORY AND DATA HANDLING:
     THE COLLECTING, COLLATING, ANALYZING,
     AND REPORTING OF INFORMATION ON LAND
     AND NATURAL RESOURCES AND ASSOCIATED
     SOCIOECONOMIC CONDITIONS.
3.   DECISION MAKING:
     CONSIDERATION OF ALTERNATIVES,
     EVALUATION OF IMPACTS OF PROPOSED          48
     ACTIONS, AND RESOLUTION OF CONFLICTS.
 PLANNING PHASES CONTD.
4. ACTION:
   CONVERTING PLANS TO ACTION.

  A GIS IS A DECISION SUPPORT
  SYSTEM THAT TRANSFORMS DATA
  INTO INFORMATION.


                                 49
AIDS USED BY GEOGRAPHERS
  1. MAPS – AN ABSTRACTION OF
     REALITY.
  2. REMOTE SENSING IMAGES OR
     PRODUCTS – ORDINARY
     TERRESTIAL PHOTOGRAPGS,
     OBLIQUE AERIAL PHOTOGRAPS,
     VERTICAL AERIAL
     PHOTOGRAPGS, SATELLITE
     IMAGES INCLUDING DIGITAL
     SATELLITE DATA.
  3. STASTICS
                                  50
  4. COMPUTERS
 BROAD QUESTIONS GIS CAN
        ANSWER
• Where is object A located? (Lat/Long, LO,
  x;y)
• Where is object A in relation to B? (Distance)
• How many occurrences of type B are there
  within distance (d) of A?
• What is the value of function z at position y?
• How large is B? (Area, perimeter, counts of
  inclusion/exclusion)

                                               51
 QUESTIONS GIS CAN ANSWER
          CONTD.
• What is the result of intersecting various kinds of
  spatial data?
• What is the path of least cost, resistance or distance
  along the ground from x to y on a path p?
• What is at points x1, x2 … ? (co-ordinates, labels)
• What objects are next to objects having certain
  combinations of attributes? (adjacency)
• Reclassify data/objects having certain combinations
  of attributes. Using the digital database as a model of
  the real world, simulate the effect of process (p) over
  time (t) for a given scenario(s).

                                                        52
53
Quickest Route




                 54
  What distinguishes GIS from
  other information systems?
• GIS makes connections between activities based on
  spatial proximity.
• GIS integrates spatial and other kinds of information
  within one system, it offers a consistent framework for
  analyzing space.
• GIS provides the mechanisms for undertaking the
  manipulation, analysis and display of geographic
  knowledge.
• Its ability to store relationships between features in
  addition to feature locations and attributes is one of the
  most important sources of power and flexibility of GIS.


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