Summary readings Introduction GIS (GEO2-3031)
Academic year 2020-2021, Utrecht University
Written by Marte Vroom
Table of content
Chapter 1: What is GIS?..........................................................................................................................3
Introduction........................................................................................................................................3
Defining GIS........................................................................................................................................5
Components of a GIS..........................................................................................................................6
Chapter 2: Spatial data...........................................................................................................................7
Introduction........................................................................................................................................7
Maps and their influence on the character of spatial data.................................................................8
Thematic characteristics of spatial data...........................................................................................11
Other sources of spatial data............................................................................................................12
Chapter 3: Spatial data modelling........................................................................................................13
Introduction......................................................................................................................................13
Entity definition................................................................................................................................14
Spatial data models..........................................................................................................................14
Spatial data structures......................................................................................................................15
Modelling surfaces...........................................................................................................................16
Modelling networks..........................................................................................................................17
Building computer worlds.................................................................................................................17
Modelling the third dimension.........................................................................................................18
Modelling the fourth dimension.......................................................................................................18
Chapter 5: Data input and editing........................................................................................................19
Introduction......................................................................................................................................19
Methods of data input......................................................................................................................20
Data editing......................................................................................................................................24
Towards an integrated database......................................................................................................25
Chapter 6: Data analysis.......................................................................................................................26
Introduction......................................................................................................................................26
Measurements in GIS – lengths, perimeters and areas....................................................................27
Queries.............................................................................................................................................27
Reclassification.................................................................................................................................27
Buffering and neighbourhood functions...........................................................................................28
Integrating data – map overlay.........................................................................................................28
Spatial interpolation.........................................................................................................................29
1
, Analysis of surfaces..........................................................................................................................30
Network analysis..............................................................................................................................31
Chapter 7: Analytical modelling in GIS..................................................................................................32
Introduction......................................................................................................................................32
Process models.................................................................................................................................33
Modelling physical and environmental processes............................................................................34
Modelling human processes.............................................................................................................34
Modelling the decision-making process...........................................................................................35
Problems with using GIS to model spatial processes........................................................................36
Chapter 8: Output: from new maps to enhanced decisions.................................................................37
Introduction......................................................................................................................................37
Maps as output.................................................................................................................................38
Non-cartographic output..................................................................................................................40
Spatial multimedia............................................................................................................................40
Mechanisms of delivery....................................................................................................................40
GIS and spatial decision support.......................................................................................................40
Chapter 9: The development of computer methods for handling spatial data.....................................41
Introduction......................................................................................................................................41
Handling spatial data........................................................................................................................41
The development of computer methods for handling spatial data..................................................42
The development of GIS...................................................................................................................43
Chapter 10: Data quality issues............................................................................................................44
Introduction......................................................................................................................................44
Describing data quality and errors....................................................................................................45
Sources of error in GIS......................................................................................................................45
Finding and modelling errors in GIS..................................................................................................47
Managing GIS error...........................................................................................................................48
Chapter 11: Human and organizational issues.....................................................................................49
Introduction......................................................................................................................................49
GIS applications................................................................................................................................50
GIS users...........................................................................................................................................51
Justifying the investment in GIS........................................................................................................52
Choosing and implementing a GIS....................................................................................................53
Organizational changes due to GIS...................................................................................................55
Geertman: Planning Support Systems (PSS) as research instruments..................................................56
Introduction......................................................................................................................................56
2
, Planning support..............................................................................................................................57
Instruments for planning support.....................................................................................................57
Research application of PSS..............................................................................................................58
Recommendations for PSS research.................................................................................................59
Kraak: Statistical mapping....................................................................................................................60
Statistical surveys.............................................................................................................................60
Data analysis.....................................................................................................................................61
Data classification.............................................................................................................................62
Cartographical data analysis.............................................................................................................63
Mapping methods............................................................................................................................64
Chapter 1: What is GIS?
Introduction
GIS has particular value when you need to answer questions about:
3
, 1. Location – example: nearest bookshop
Generic question: Where are particular features found?
2. Patterns – example: where high concentrations of students live in a city
Generic question: What geographical patterns exist?
3. Trends – example: how patterns of retailing are changing in response to development of out-
of-town superstores
Generic question: Where have changes occurred over a given period?
4. Conditions – example: where to find a holiday accommodation that is within 1 km of a wind
surfing beach and accessible by public transport
Generic question: Where do certain conditions apply?
5. Implications – example: if someone moves to a new home in a location, how far will it be
from the office, gym or coffee shop?
Generic question: What will the spatial implications be if an organization takes certain
action?
There are three types of GIS application:
Searching for sites
GIS application. Using siting factors to find a location/site, following a rational procedure for
site identification. GIS techniques allows quick remodeling for slight changes in siting criteria,
and produce results as maps eminently suitable for presentation at public enquiries. GIS
software can be used to combine new data layers with additional layers of information
representing other siting criteria. Final result will be a map showing locations where all the
specified siting criteria were satisfied. Allows comparative re-evaluation and testing of data
and conditions. Three issues associated with GIS: 1) the problem of errors in spatial data sets;
2) the difficulty in establishing criteria for abstract spatial concepts; and 3) the potential value
of using GIS to communicate ideas. Examples:
o Find a site for a new retail outlet
o Find a site for a new oil terminal
o Find a site for a new airport
o Find a location for radioactive waste
Evaluating land use planning
GIS application. GIS as a tool to help with policy formulation. Bring together disparate data
and information about the character and activities that take place in a region, using data
such as maps, aerial photographs and socio-economic surveys. Sources can be used: 1) paper
maps (soil type and geology); 2) contour maps (topography); 3) ecological field maps
(drainage conditions); and 4) remote sensing (land use). Three issues associated with GIS: 1)
deciding which map projection to adopt as the common frame of reference; 2) GIS can be
used to create models of environmental processes with maps used as the building blocks for
the model; and 3) bringing people together to search for a solution to a common problem is
often difficult. Example:
o Identify areas of the landscape for conservation
Finding a new home
Find a suitable location using a decision support system with a series of factors, such as
insurance costs, proximity to schools and roads. First a weighting process will be completed
using factors reflecting importance and constraints excluding certain areas. Data selected will
be combined in a GIS using a multi-criteria modelling technique. Information on the map
should be linked with a database of certain features; attribute data. Three issues associated
with GIS: 1) clear understanding of the way GIS software works is crucial if you are to be able
4
Academic year 2020-2021, Utrecht University
Written by Marte Vroom
Table of content
Chapter 1: What is GIS?..........................................................................................................................3
Introduction........................................................................................................................................3
Defining GIS........................................................................................................................................5
Components of a GIS..........................................................................................................................6
Chapter 2: Spatial data...........................................................................................................................7
Introduction........................................................................................................................................7
Maps and their influence on the character of spatial data.................................................................8
Thematic characteristics of spatial data...........................................................................................11
Other sources of spatial data............................................................................................................12
Chapter 3: Spatial data modelling........................................................................................................13
Introduction......................................................................................................................................13
Entity definition................................................................................................................................14
Spatial data models..........................................................................................................................14
Spatial data structures......................................................................................................................15
Modelling surfaces...........................................................................................................................16
Modelling networks..........................................................................................................................17
Building computer worlds.................................................................................................................17
Modelling the third dimension.........................................................................................................18
Modelling the fourth dimension.......................................................................................................18
Chapter 5: Data input and editing........................................................................................................19
Introduction......................................................................................................................................19
Methods of data input......................................................................................................................20
Data editing......................................................................................................................................24
Towards an integrated database......................................................................................................25
Chapter 6: Data analysis.......................................................................................................................26
Introduction......................................................................................................................................26
Measurements in GIS – lengths, perimeters and areas....................................................................27
Queries.............................................................................................................................................27
Reclassification.................................................................................................................................27
Buffering and neighbourhood functions...........................................................................................28
Integrating data – map overlay.........................................................................................................28
Spatial interpolation.........................................................................................................................29
1
, Analysis of surfaces..........................................................................................................................30
Network analysis..............................................................................................................................31
Chapter 7: Analytical modelling in GIS..................................................................................................32
Introduction......................................................................................................................................32
Process models.................................................................................................................................33
Modelling physical and environmental processes............................................................................34
Modelling human processes.............................................................................................................34
Modelling the decision-making process...........................................................................................35
Problems with using GIS to model spatial processes........................................................................36
Chapter 8: Output: from new maps to enhanced decisions.................................................................37
Introduction......................................................................................................................................37
Maps as output.................................................................................................................................38
Non-cartographic output..................................................................................................................40
Spatial multimedia............................................................................................................................40
Mechanisms of delivery....................................................................................................................40
GIS and spatial decision support.......................................................................................................40
Chapter 9: The development of computer methods for handling spatial data.....................................41
Introduction......................................................................................................................................41
Handling spatial data........................................................................................................................41
The development of computer methods for handling spatial data..................................................42
The development of GIS...................................................................................................................43
Chapter 10: Data quality issues............................................................................................................44
Introduction......................................................................................................................................44
Describing data quality and errors....................................................................................................45
Sources of error in GIS......................................................................................................................45
Finding and modelling errors in GIS..................................................................................................47
Managing GIS error...........................................................................................................................48
Chapter 11: Human and organizational issues.....................................................................................49
Introduction......................................................................................................................................49
GIS applications................................................................................................................................50
GIS users...........................................................................................................................................51
Justifying the investment in GIS........................................................................................................52
Choosing and implementing a GIS....................................................................................................53
Organizational changes due to GIS...................................................................................................55
Geertman: Planning Support Systems (PSS) as research instruments..................................................56
Introduction......................................................................................................................................56
2
, Planning support..............................................................................................................................57
Instruments for planning support.....................................................................................................57
Research application of PSS..............................................................................................................58
Recommendations for PSS research.................................................................................................59
Kraak: Statistical mapping....................................................................................................................60
Statistical surveys.............................................................................................................................60
Data analysis.....................................................................................................................................61
Data classification.............................................................................................................................62
Cartographical data analysis.............................................................................................................63
Mapping methods............................................................................................................................64
Chapter 1: What is GIS?
Introduction
GIS has particular value when you need to answer questions about:
3
, 1. Location – example: nearest bookshop
Generic question: Where are particular features found?
2. Patterns – example: where high concentrations of students live in a city
Generic question: What geographical patterns exist?
3. Trends – example: how patterns of retailing are changing in response to development of out-
of-town superstores
Generic question: Where have changes occurred over a given period?
4. Conditions – example: where to find a holiday accommodation that is within 1 km of a wind
surfing beach and accessible by public transport
Generic question: Where do certain conditions apply?
5. Implications – example: if someone moves to a new home in a location, how far will it be
from the office, gym or coffee shop?
Generic question: What will the spatial implications be if an organization takes certain
action?
There are three types of GIS application:
Searching for sites
GIS application. Using siting factors to find a location/site, following a rational procedure for
site identification. GIS techniques allows quick remodeling for slight changes in siting criteria,
and produce results as maps eminently suitable for presentation at public enquiries. GIS
software can be used to combine new data layers with additional layers of information
representing other siting criteria. Final result will be a map showing locations where all the
specified siting criteria were satisfied. Allows comparative re-evaluation and testing of data
and conditions. Three issues associated with GIS: 1) the problem of errors in spatial data sets;
2) the difficulty in establishing criteria for abstract spatial concepts; and 3) the potential value
of using GIS to communicate ideas. Examples:
o Find a site for a new retail outlet
o Find a site for a new oil terminal
o Find a site for a new airport
o Find a location for radioactive waste
Evaluating land use planning
GIS application. GIS as a tool to help with policy formulation. Bring together disparate data
and information about the character and activities that take place in a region, using data
such as maps, aerial photographs and socio-economic surveys. Sources can be used: 1) paper
maps (soil type and geology); 2) contour maps (topography); 3) ecological field maps
(drainage conditions); and 4) remote sensing (land use). Three issues associated with GIS: 1)
deciding which map projection to adopt as the common frame of reference; 2) GIS can be
used to create models of environmental processes with maps used as the building blocks for
the model; and 3) bringing people together to search for a solution to a common problem is
often difficult. Example:
o Identify areas of the landscape for conservation
Finding a new home
Find a suitable location using a decision support system with a series of factors, such as
insurance costs, proximity to schools and roads. First a weighting process will be completed
using factors reflecting importance and constraints excluding certain areas. Data selected will
be combined in a GIS using a multi-criteria modelling technique. Information on the map
should be linked with a database of certain features; attribute data. Three issues associated
with GIS: 1) clear understanding of the way GIS software works is crucial if you are to be able
4
