Geografiske informasjonssystemer GIS SGO 1910 SGO 4930

Geografiske informasjonssystemer (GIS) SGO 1910 & SGO 4930 Vår 2004 Foreleser: Karen O’Brien (karen. obrien@cicero. uio. no) Seminarleder: Gunnar Berglund (gunnarbe@student. sv. uio. no)

Course Objectives n n n To provide students with a basic understanding of geographic information science; To provide students with practical experience in using Arc. GIS software; To apply both theory and practice to a real research project (”Oslo project”).

Readings: n Longley, P. A. , Goodchild, M. F. , Maguire, D. J. , and D. W. Rhind. 2001. Geographic Information Systems and Science. Chichester: John Wiley and Sons, 454 pp. Reading for Oslo Project: Wessels, T. 2001. Losing control? Inequality and Social Divisions in Oslo. European Planning Studies, 9, 7, 889 -906. Wessels, T. 2000. Social polarisation and socio-economic segregation in a welfare state: the case of Oslo. Urban Studies, 33, 11, 1947 -1967.

Grading n n 30% Six laboratory assignments (5 points each) 20% Two mid-term quizzes (10 points each) (Uke 6 & Uke 10) 25% Final Project (25 points) 25% Final Exam (25 points)

Lab Assignments n n n Submitted on your own home page Due dates: two weeks after each lab Criteria for evaluation will be provided with each lab

GIS Labs n n n Arc. GIS 8. 0 (GIS) Excel (data base files) Hot Metal (web pages) Adobe Photoshop (sizing maps and pictures) Win. Zip (decompressing files)

Mid-term quizzes n n n Each quiz worth 10 points Multiple choice, true-false questions based on readings and lectures 45 minutes to complete the quiz

Project n n Identify a problem or question to address related to Oslo; Collect and edit data (including new data with a GPS); Use GIS to map and analyze data; Present results. Due: May 3 rd, 2004

Final Exam n n n 28. mai kl. 09: 00 (3 timer) Essays, short answer, multiple choice, true-false Based on lectures, readings, and labs

Masters Students n n a brief review of two academic articles that use GIS in relation to the student’s field of interest (urban geography, development geography, political geography, etc. ); a discussion of potential ways that GIS can contribute to their masters thesis (e. g. , mapping, analysis, etc. ); identification of data sources related to their thesis (this can be general if no thesis topic has been chosen); an outline of the steps that need to be taken to use GIS in thesis (for example, an outline of the steps involved in making a map of Ghana showing population density and road networks).

Questions My office hours: Tuesdays, 9. 30 – 11. 00 (Room 321) (or by appointment, at CICERO) n Lab assistance: Thursdays, 9. 30 – 11. 00 n

Why take this course? n n GIS is a useful tool with a wide range of applications; GIS is a skill that is in demand, with a growing market; Geographers have numerous advantages related to GIS; GIS is challenging (but fun!)

What is a GIS? 1. 2. A computer system capable of holding and using data describing places on the earth’s surface. An organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update manipulate, analyze, and display all forms of geographically referenced information.

Geographic Information System n Organized collection of • Hardware • Software • Network • Data • People • Procedures Software People Data Network Procedures Hardware

”A GIS by any other name” n n n Land Information System Delivery Routing System Emergency Response System Disaster Planning System Crime Monitoring System Real Estate ”Homefinder” System

Why is GIS Important? n n n Provides a consistent framework for integrating spatial and other kinds of information within a single system (ideal for interdisciplinary work). Permits manipulation and display of geographical (digital) data in new ways. Makes connections between activities based on geographic location.

What can a GIS do? n n n Location (Where is it. . . ) Condition (What is it. . . ) Trend (What has changed. . . ) Pattern (What is the pattern. . . ) Routing (Which is the ’best’ way. . . ) Modeling (What if. . . )

A Brief History of GIS n n GIS’s origins lie in thematic cartography. Many planners used the method of map overlay using manual techniques. Manual map overlay as a method was first described comprehensively by Jacqueline Tyrwhitt in a 1950 planning textbook. Hc. Harg used blacked out transparent overlays for site selection in Design with Nature.

Map Overlay

A Brief History of GIS (cont. ) n n The 1960 s saw many new forms of geographic data and mapping software. Computer cartography developed the first basic GIS concepts during the late 1950 s and 1960 s. Linked software modules, rather than stand-alone programs, preceded GISs. The Harvard University ODYSSEY system was influential due to its topological arc-node (vector) data structure.

A Brief History of GIS (cont. ) n n n GIS was significantly altered by (1) the PC and (2) the workstation. During the 1980 s, new GIS software could better exploit more advanced hardware. User Interface developments led to GIS's vastly improved ease of use during the 1990 s. During the 1990 s, new GIS software could better exploit more advanced hardware. So far in the 2000 s: • Internet becomes major deliver vehicle for GIS • More than 1 million active users of GIS • GIS is linking to other technologies (e. g. mobile phones, palmtops, etc. )

Interest in GIS is Rising n n n n n Applications via Internet Price reductions Greater awareness Improved ease of use Better technology Proliferation of data Commercial software packages Real applications Proven cost: benefit cases

Business of GIS n GIS industry is worth over $7 billion • Software • Data • Services • Publishing • Education

GISystems, GIScience and GIStudies n GISystems • Emphasis on technology and tools n GIScience • Fundamental issues raised by the use of GIS and related technologies n n n Spatial analysis Map projections Accuracy Scientific visualization GIStudies • Systematic study of the use of geographic information

Sources of Information on GIS n n The amount of information available about GIS can be overwhelming. Sources of GIS information include journals and magazines, books, professional societies, the World Wide Web, and conferences. GIS has Web Home pages, network conference groups, professional organizations, and user groups. Most colleges and universities now offer GIS classes in geography departments.

GIS Resources: Conferences

GIS Konferans: Oslo Plaza 4. -6. februar 2004 • Geodata og ARCen ønsker for 15. gang alle GISinteresserte velkommen til tre fullspekkede og interessante dager! Konferansen henvender seg som vanlig til alle våre brukere, men også til deg som er ny i GIS verdenen. Programmet består av fire parallelle sesjoner hvor det presenteres et bredt spekter av tema innenfor blant annet innsamling, forvaltning, analyse og presentasjon av geografiske data. Her får du muligheten til å skape kontakter og få inspirasjon fra andre innen samme interesseområde. For den som er interessert i teknikk, byr vi på rundt 30 minikurs hvor du får opplæring av konsulenter fra Geodata. • Pris: 150 NOK ( dagsbesøk) Se: http: //www. geodata. no/custom/program 2004. htm

GIS Resources: Glossies

Major GIS-Only Journals n n n International Journal of Geographical Information Systems Geographical Systems Transactions in GIS Geo Info Systems GIS World

Specialty Journals n n n Business Geographics GIS Law Grass. Clippings GIS Asia/Pacific GIS World Report/CANADA GIS Europe

Regular GIS Papers n n n n Annals of the Association of American Geographers Cartographica Cartography and GIS Computer; Computers, Environment, and Urban Systems Computers and Geosciences IEEE Transactions on Computer Graphics and Applications Photogrammetric Engineering and Remote Sensing

Occasional GIS papers n n n n n Cartographic Perspectives Cartographica Journal of Cartography Geocarto International IEEE Geosciences International Journal of Remote Sensing Landscape Ecology Remote Sensing Review Mapping Science and Remote Sensing Infoworld

Popular Distribution Magazines n n n Business Geographics Geo Info Systems GIS Law GIS World GPS World GEODATA

Part II: Thinking Spatially n n n What is spatial data? How can spatial data be represented digitally? Rasters and vector models

n n n Geographic problems usually involve location. GIS – A special class of information systems that keep track of events, activities and things, but also where these events, activities, or things happen or exist. The difference between GIS and basic mapping and spreadsheet programs lies in its ability to handle spatial data.

The Nature of Spatial Data n n n Distributed through space Can be observed or described in the real world and identified by geographical location Change through space and time

Spatial and non-spatial data

Map of Bosnia and Heregovina

Spatial is Special n n n Geographic – Earth’s surface and near-surface Spatial – any space (including geographic) e. g. medical imaging Geospatial – synonymous with geographic

Sensing the World n Personal experience limited in time and space • One human lifetime • A small fraction of the planet’s surface n n All additional knowledge comes from books, the media, movies, maps, images, and other information sources From indirect or “remote” sensing

Representations n n Are needed to convey information Fit information into a standard form or model • In the diagram the colored trajectories consist only of a few straight lines connecting points n Almost always simplify the truth that is being represented • There is no information in the representation about daily journeys to work and shop, or vacation trips out of town

Representations Occur: n n In the human mind, when information is acquired through the senses and stored in memory In photographs, which are twodimensional models of light received by the camera In written text, when information is expressed in words In numbers that result from measurements

Digital Representation n Uses only two symbols, 0 and 1, to represent information (e. g. , 1111 = 15) The basis of almost all modern human communication Many standards allow various types of information to be expressed in digital form • • MP 3 for music JPEG for images ASCII for text GIS relies on standards for geographic data

Why Digital? n Economies of scale • One type of information technology for all types of information n n Simplicity Reliability • Systems can be designed to correct errors n Easily copied and transmitted • At close to the speed of light

Accuracy of Representations n Representations can rarely be perfect • Details can be irrelevant, or too expensive and voluminous to record n It’s important to know what is missing in a representation • Representations can leave us uncertain about the real world

The Fundamental Problem n Geographic information links a place, and often a time, with some property of that place (and time) • “The temperature at 34 N, 120 W at noon local time on 12/2/99 was 18 Celsius” n The potential number of properties is vast • In GIS we term them attributes • Attributes can be physical, social, economic, demographic, environmental, etc.

The Fundamental Problem (cont. ) n The number of places and times is also vast • Potentially infinite n The more closely we look at the world, the more detail it reveals • Potentially ad infinitum • The geographic world is infinitely complex n Humans have found ingenious ways of dealing with this problem • Many methods are used in GIS to create representations or data models

Discrete Objects and Fields n n Two ways of conceptualizing or modeling geographic variation The most fundamental distinction in geographic representation

Discrete Objects n n Points, lines, and areas Countable Persistent through time, perhaps mobile Biological organisms • Animals, trees n Human-made objects • Vehicles, houses, fire hydrants

Fields n Properties that vary continuously over space • Value is a function of location • Property can be of any attribute type, including direction n Elevation as the archetype • A single value at every point on the Earth’s surface • The source of metaphor and language n Any field can have slope, gradient, peaks, pits

Examples of Fields n n Soil properties, e. g. p. H, soil moisture Population density • But at fine enough scale the concept breaks down n Identity of land owner • A single value of a nominal property at any point n n Name of county or state or nation Atmospheric temperature, pressure

Rasters and Vectors n n How to represent phenomena conceived as fields or discrete objects? Raster • Divide the world into square cells • Register the corners to the Earth • Represent discrete objects as collections of one or more cells • Represent fields by assigning attribute values to cells • More commonly used to represent fields than discrete objects

A raster data model uses a grid. n n One grid cell is one unit or holds one attribute. Every cell has a value, even if it is “missing. ” A cell can hold a number or an index value standing for an attribute. A cell has a resolution, given as the cell size in ground units.

Generic structure for a grid Grid extent Rows Grid cell Resolution Columns Figure 3. 1 Generic structure for a grid.

Legend Mixed conifer Douglas fir Oak savannah Grassland Raster representation. Each color represents a different value of a nominalscale field denoting land cover class.

Characteristics of Rasters n Pixel size • The size of the cell or picture element, defining the level of spatial detail • All variation within pixels is lost n Assignment scheme • The value of a cell may be an average over the cell, or a total within the cell, or the commonest value in the cell • It may also be the value found at the cell’s central point

The mixed pixel problem

Vector Data n n Used to represent points, lines, and areas All are represented using coordinates • One per point • Areas as polygons n n Straight lines between points, connecting back to the start Point locations recorded as coordinates • Lines as polylines n Straight lines between points

The Vector Model n A vector data model uses points stored by their real (earth) coordinates. Lines and areas are built from sequences of points in order. Lines have a direction to the ordering of the points. Polygons can be built from points or lines. n Vectors can store information about topology. n n n

Raster vs Vector n Volume of data • Raster becomes more voluminous as cell size decreases n Source of data • Remote sensing, elevation data come in raster form • Vector favored for administrative data n Software • Some GIS better suited to raster, some to vector

Building complex features n n n Simple geographic features can be used to build more complex ones. Areas are made up of lines which are made up of points represented by their coordinates. Areas = {Lines} = {Points}

Areas are lines are points are coordinates

Properties of Features n n n n size distribution pattern contiguity neighborhood shape scale orientation.

Basic properties of geographic features