Introduction to GIS 1
Introduction to GIS
http://www.sli.unimelb.edu.au/gisweb/
Dr F. Escobar, Assoc Prof G. Hunter, Assoc Prof I. Bishop, Dr A. Zerger
Department of Geomatics, The University of Melbourne
Introduction to GIS ........................................................................................................................ 1
INTRODUCTION ............................................................................................................................... 2
Definition of GIS ....................................................................................................................... 2
GIS applications ....................................................................................................................... 3
Geospatial data ........................................................................................................................ 3
data for GIS applications........................................................................................................... 4
digital representation of geospatial data.................................................................................... 4
VECTOR BASED GIS ....................................................................................................................... 4
general definitions..................................................................................................................... 4
Vector representation of data.................................................................................................... 5
vector models ........................................................................................................................... 5
data bases................................................................................................................................ 9
RASTER BASED GIS...................................................................................................................... 10
raster representation of data................................................................................................... 10
grid size and resolution........................................................................................................... 10
raster data structures.............................................................................................................. 10
advantages/disadvantages of raster and vector data models................................................... 12
data capture ........................................................................................................................... 12
rasterisation of vector data...................................................................................................... 12
raster to vector conversion...................................................................................................... 12
REFERENCES ............................................................................................................................... 13
, Introduction to GIS 2
Introduction
Definition of GIS
Like the field of geography, the term Geographic Information System (GIS) is hard to define. It
represents the integration of many subject areas. Accordingly there us no absolutely agreed upon
definition of a GIS (deMers, 1997). A broadly accepted definition of GIS is the one provided by the
National Centre of Geographic Information and Analysis:
a GIS is a system of hardware, software and procedures to facilitate the management, manipulation, analysis,
modelling, representation and display of georeferenced data to solve complex problems regarding planning and
management of resources (NCGIA, 1990)
Geographic information systems have emerged in the last decade as an essential tool for urban and
resource planning and management. Their capacity to store, retrieve, analyse, model and map large
areas with huge volumes of spatial data has led to an extraordinary proliferation of applications.
Geographic information systems are now used for land use planning, utilities management,
ecosystems modelling, landscape assessment and planning, transportation and infrastructure
planning, market analysis, visual impact analysis, facilities management, tax assessment, real estate
analysis and many other applications.
Functions of GIS include: data entry, data display, data management, information retrieval and
analysis.
A more comprehensive and easy way to define GIS is the one that looks at the disposition, in layers
(Figure 1 ), of its data sets. "Group of maps of the same portion of the territory, where a given location
has the same coordinates in all the maps included in the system". This way, it is possible to analyse
its thematic and spatial characteristics to obtain a better knowledge of this zone.
Introduction to GIS
http://www.sli.unimelb.edu.au/gisweb/
Dr F. Escobar, Assoc Prof G. Hunter, Assoc Prof I. Bishop, Dr A. Zerger
Department of Geomatics, The University of Melbourne
Introduction to GIS ........................................................................................................................ 1
INTRODUCTION ............................................................................................................................... 2
Definition of GIS ....................................................................................................................... 2
GIS applications ....................................................................................................................... 3
Geospatial data ........................................................................................................................ 3
data for GIS applications........................................................................................................... 4
digital representation of geospatial data.................................................................................... 4
VECTOR BASED GIS ....................................................................................................................... 4
general definitions..................................................................................................................... 4
Vector representation of data.................................................................................................... 5
vector models ........................................................................................................................... 5
data bases................................................................................................................................ 9
RASTER BASED GIS...................................................................................................................... 10
raster representation of data................................................................................................... 10
grid size and resolution........................................................................................................... 10
raster data structures.............................................................................................................. 10
advantages/disadvantages of raster and vector data models................................................... 12
data capture ........................................................................................................................... 12
rasterisation of vector data...................................................................................................... 12
raster to vector conversion...................................................................................................... 12
REFERENCES ............................................................................................................................... 13
, Introduction to GIS 2
Introduction
Definition of GIS
Like the field of geography, the term Geographic Information System (GIS) is hard to define. It
represents the integration of many subject areas. Accordingly there us no absolutely agreed upon
definition of a GIS (deMers, 1997). A broadly accepted definition of GIS is the one provided by the
National Centre of Geographic Information and Analysis:
a GIS is a system of hardware, software and procedures to facilitate the management, manipulation, analysis,
modelling, representation and display of georeferenced data to solve complex problems regarding planning and
management of resources (NCGIA, 1990)
Geographic information systems have emerged in the last decade as an essential tool for urban and
resource planning and management. Their capacity to store, retrieve, analyse, model and map large
areas with huge volumes of spatial data has led to an extraordinary proliferation of applications.
Geographic information systems are now used for land use planning, utilities management,
ecosystems modelling, landscape assessment and planning, transportation and infrastructure
planning, market analysis, visual impact analysis, facilities management, tax assessment, real estate
analysis and many other applications.
Functions of GIS include: data entry, data display, data management, information retrieval and
analysis.
A more comprehensive and easy way to define GIS is the one that looks at the disposition, in layers
(Figure 1 ), of its data sets. "Group of maps of the same portion of the territory, where a given location
has the same coordinates in all the maps included in the system". This way, it is possible to analyse
its thematic and spatial characteristics to obtain a better knowledge of this zone.
