Prof. Dr.-Ing. Ralf Bill GI Basics Introduction to GIS 1 Rostock University, Chair for Geodesy and Geoinformatics X 2007 Introduction to GIS Prof. Dr.-Ing. Ralf Bill and Dr. Edward Nash Rostock University Info-Systems GIS-Definition Spatial ref. Data types Functions Summary Literature Rostock University, Chair for Geodesy and Geoinformatics GI_Basics -2- Integer number 248 2D-Point in GK- Meridian system Building No 12 Logo of Institute Information Information system K n o w l e d g e , T r a n s f o r m a t i o n , R u l e s ? Expert system Binary represen- tation (8Bit) Legend of map Knowledge Gauß-Krüger- Coordinates Experience Data base system ...011111000100... Data 12 3451278,35 5336412,46 Data, Information, Knowledge Information systems
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Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 1
Rostock University, Chair for Geodesy and Geoinformatics X 2007
Introduction to GIS
Prof. Dr.-Ing. Ralf Bill and Dr. Edward NashRostock University
Info-Systems
GIS-Definition
Spatial ref.
Data types
Functions
Summary
Literature
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 2 -
Integer number 248
2D-Point in GK-Meridian system
Building No 12
Logo of Institute
Information
Informationsystem
Kno
wle
dge,
Tra
nsfo
rmat
ion,
Rul
es
?
Expert system
Binary represen-tation (8Bit)
Legend of map
Knowledge
Gauß-Krüger-Coordinates
Experience
Data basesystem
...011111000100...
Data
12
3451278,355336412,46
Data, Information, Knowledge
Information system
s
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 2
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 3 -
12
Reference: K. Greve, 1995
°CWhat How
WhoWhen
WhereInside what ???
H
H--C
H
C O
H
H
H
Information = data + contextInform
ation systems
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 4 -
Information systems
• A system is a set of elements that are interrelated.
• Information systems are general tools to manage and analyse data.• Information systems are based on databases and their database
management systems (DBMS).
• An information system is basically a “question / answer” system for a set of data.
Information system
s
Question
Answer
QuestionAnswer
Questi
on
Answer
Question
Answer
DBMS
Information system
Application 1
Application 2
Application 3
Application n
Data
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 3
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 5 -
Elements and types of information systems
User
Hardware
Software Data
H HardwareS SoftwareD DataU User
Processors, MachinesPrograms, MethodsData, Knowledge, RulesUser, People
~ 3-5 years~ 7-10 years~ 25 years
Types of IS: Management information systemsTourism information systemsBank information systemsFlight reservation systems
Information system
s
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 6 -
'Geo' – the magic linking element
a) Global
b) Regional
Nordsee
Ostsee
Berlin
Hamburg
München
FrankfurtBonn
Stuttgart
c) Local (horizontal)
3
2
4
Curve street
Max-Bill-Street
Fritsch-path1
31
24
ge|o..., Ge|o..., (greek. gẽ, gaĩa) "Earth“
All information issomehow related to theEarth or parts of it, i.e.it is spatially referenced
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 4
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 7 -
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 9 -
Time of thePioneers(experi-mental)
Time of the Adminis-trations(start)
Time of theCompanies(first real GISproducts onthe market)
Time of the User(special GIS packages)
Time of theOpen Market(GI as a commodity,Open GIS)
1960-1975 1975-1985 1980-1990 1990-2000 Since 2000
• Term GIS ca.1960 (MIT, Boston)• 1960s first country-wide approach (CLDS, Canada)• Term LIS ca. 1970, first specialisation (FIG, 1973)• Lots of other terms up to the 1990s such as
• Term GIS ca.1960 (MIT, Boston)• 1960s first country-wide approach (CLDS, Canada)• Term LIS ca. 1970, first specialisation (FIG, 1973)• Lots of other terms up to the 1990s such as
- others: e.g. kilometres along roads, waterways,..
Telephone book
Spatialreference
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 7
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 13 -
Municipalities use spatial data with various metrics
Examples
Administration
Statistics and election
Tax
Real estate
Rescue services
Registration office
Schools
Civil engineering
City planning
Land register/ survey
Environment
Type of spatial relationAddresses Codes Coordinates others
often sometimes not often
Spatialreference
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 14 -
Spatial references – the important link
• Around 80% of all branch-specific administrative, logistic, and strategic activities in an enterprise or governmental organisationhave a spatial reference
Geo-Information System.....
TablesGrundstücksflächen Erste Abteilung
Nr. PEigentümer
1 Resnik - 400,43
Fläche
2 Bill 3 1255,43
FilesHaus Nr. 1 - 27
Haus Nr. 1 - 25
Haus Nr. 1 - 24Haus Nr. 1 - 23Grundstück - 12353Amtsgericht - AachenFläche - 134,5 m2
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 15 -
Data in a GIS
Source: http://erg.usgs.gov/isb/pubs/gis_poster/
Contour lines Digital terrain models
Topographic maps Orthophotos
. . . .
. . . .
Data types
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 16 -
Data in a GIS
Source: http://erg.usgs.gov/isb/pubs/gis_poster/
Satellite imagery
Image classifications
Census data
Measurements
. . . .
. . . .
Data types
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 9
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 17 -
Data types in GIS: Geometrical data
Properties :Vector data- according to object lines- logical structure- well-known methods of acquisition- small amount of dataRaster data- according to position- limited logical structure- simple data acquisition- large amount of data
Point
Line
x,y-coord. Pixels
Pixels
Digital Analogue Digital AnalogueElement Vector Raster
x,y-coord.-sequence
Polygon closedx y coord.-sequence
Pixels
• Geometrical elements are points, lines and polygons in vector form, pixels in raster form.
• They are defined in a coordinate system and describe the shape and position of objects.
• They may occur in analogue and/or digital, vector and/or raster form.
• Coordinates carry the geometric information.• Mathematical basis: Computational geometry
Data types
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 18 -
2D - Planimetry
1251
125
125 125
3
2 4
2D+1D - Planimetry + DTM(no link between position and height)
1251
125
125 125
3
2 4
2.5D - x,y,z
125
1
125
125 125
3
2 4
527.0
525.2 524.9
524.9
3D-Line model(Planimetry+ link to DTM)
3D-facet model 3D-Volume model
Geometrical dimensions
Data types
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 10
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 19 -
Data types in GIS: Topological data
• Topological elements are nodes (0-cells), edges (1-cells) and meshes (2-cells).
• Describe geometry without coordinates (so-called neighbourhood relations) and are invariant towards topologic transformations.
• The edge carries the topological information.• Mathematical basis: Topology, Graph theory
Geometrically not equal.. but ..
Topologically equal
Data types
4 6 3f e
dga
1 5 2b c
125 126
12
364 f
a
b c
dg125 126
5
e
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 20 -
Data types in GIS: Graphical descriptions
- are found in analogue form (e.g. map) and digital form (e.g. screen graphic).
-usually have additional text elements in order to match standard graphic elements.
Object repres.
Fill type:
Line type:
Symbol type:
Attribute-type
Filltype
Linetype
Symboltype
Attribute type: Font Height Width Orient. Distanc. Direction
Pattern Border lineAreafill Scale
TypeRepeating
symbolsParallelLines Color Scale
OriginMaskingPrimitives Scale
• Graphic data = geometry data + graphical descriptions (styles)
• Graphical descriptions such as symbols, hatching, grey scales, line sizes, polygon fill etc.
• Basis: Cartography, Visualisation
Data types
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 11
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 21 -
Data types in GIS: Attributes
• Attributes, descriptive data, special data.• Name all non-geometric elements such as text,
numbers, measurements etc.• Are captured in a special context to solve special
problems.• Occur in analogue form as well as digital.• Mathematical basis: Set theory, Relational algebra.
Grey valuesParcel numberStreet namePoint number
128
A-stre
et
128/1 64=field64,126,32=forest
Analogue
ProtocolsRegistersNotes..
Digital
Data basesInformation systemsFiles..
Data types
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 22 -
Object classes represent real world phenomena
Object class catalogue• is the collection of all definedobject classes,• may be further structuredhierarchically into object groups(e.g. vegetation area) and objectdomains (e.g. vegetation).
• Types of objects in the real world (fromthe special thematic view), • which attributes (for all objects of thisclass!) characterise the individual object,• which expressions (domains) theattributes can adopt,• has possibly object class code,• has topologic type (node, edge, mesh),• has characteristic attributes (e.g. treespecies),• defines domain (oak, beech, chestnut), form and status,• defines at least one form of visualisation.
Data types
Topologic typeObject class code Visualisation3321 Polygonal Green, filled
ConiferousDecidous..
Attribute definition
Object class: Forest
Object group: Vegetation
belongs to
has has has has
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 12
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 23 -
Basic object classes and spatial relations in municipalities
BuildingsCoordinatesStreet, House No.Real Estate No.(Re.-No.)
ParcelsCoordinatesStreet, House no.Re.-No.
StreetsCoordinatesStreet NameStreet type
Building BlocksCoordinatesStreet NamesBlock No.
QuartersCoordinatesName
CityCoordinatesName
1251
120 KTV
....
....
Main street
Data types
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 24 -
Objects/features represent concrete things
• Object/feature• is an individual occurence in an object class,• is one out of many similar things belonging to one class,• is a concrete, geometrically delimited, feature,• is called an instance (data base theory).
Data types
e.g. Object class „Street“Relational data model = tabular data structureStreet {Topotype, Geometry, area, perimeter, linelength, street type, surface,
speed restriction, direction ....}
StreetTopotype Geometry Area Perimeter linelength surface pavement speed
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 28 -
From landscape to geoinformation processingLandscapeReal world
Capture
A
B 1234567
GIS
Processing
Visualisation
I
M
A
P
GIS
-Functions
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 15
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 29 -
Input / capture of information in GIS
• Getting the data/information into the system by:• Geodetic methods• Photogrammetric methods• Remote sensing• Digitising/scanning• Attribute data collection• Integrating existing digital information• Defining their spatial reference systems• ….
GIS
-Functions
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 30 -
Management of information in GIS
• Data models• Entity-Relationship-Modelling• Relational data models• Object-Oriented modelling /
Unified Modeling Language
• Data bases/information systems
GIS
-Functions
Data Base Management System (DBMS)
Data base
Files
Records
Users/Applications
Vector data Raster data
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 16
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 31 -
Analysis of information in GIS• Geometrical methods• Topological methods• Statistical methods• Set methods• Models and simulation
Ha
Be
AaFr
StBa
Dü
Nü
Mü
GIS
-Functions
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 32 -
Presentation / visualisation of information in GIS
• In analogue form:• Maps• Detail- and overview plans• Sketches• Map diagrams• Business graphics• Perspectives• Imagery• Length-/transversal profiles• Reports• Statistics• Tables• others
GIS
-Functions
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 17
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 33 -
Presentation / visualisation of information in GIS
• In electronic/digital form:• Interactive on screen• Multimedia• Fly through• Virtual- or Augmented-Reality• Animation• Digital data exchange
GIS
-Functions
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 34 -
Summary: GIS – in simple terms
• A computer system capable of holding and using data describing places on the earth's surface.
• A true GIS links spatial data with geographic information about a particular feature on the map.
• In short, a GIS doesn't hold maps or pictures - it holds a database. The heart of any GIS is the database through which questions such as what a feature is, where it is, and how it relates to other features can be answered.
• A GIS gives you the ability to associate information with a feature on a map and to create new relationships that can determine the suitability of various sites for development, evaluate environmental impact, identify the best location for a new facility, and so on.
Source: http://volusia.org/gis/whatsgis.htm
Summ
ary
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 18
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 35 -
GIS …
• links and relates multiple databases and maps together• makes maps and databases interactive• combines data from various sources• turns data into information and information into knowledge by spatial
analysis• visualises relations and patterns between features• supports exchange and sharing of data/information and knowledge• encourages cooperation and communication among different users• is becoming more and more standardised
• The power of a GIS comes from the ability to relate different information in a spatial context and to reach conclusions about this relationship.
Summ
ary
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 36 -
GIS is not ..
• .....simply a computer system for making maps, although it can create maps at different scales, in different projections, and with different colors. A GIS is an analytical tool. The major advantage of a GIS is that it allows you to identify the spatial relationship between map features. A GIS does not store a map in any conventional sense; nor does it store a particular image or view of a geographic area. Instead, a GIS stores the data from which you can draw a desired view to suit a particular purpose.
• … spreadsheets, statistics packages or drafting packages, CAD or data base systems, GPS etc.. Instead it makes use of all of these packages and their functionalities to analyse real world phenomena.
• .. a static map – neither in analogue (paper) nor in digital form. Maps are often a “product” of a GIS. They are simply a way to visualize the results of spatial analysis => thematic maps.
Source: http://volusia.org/gis/whatsgis.htm
Summ
ary
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 19
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 37 -
GIS-Feasibilities and Impossibilities
• What is a GIS able to do?• Illustrate facts quickly and graphically
• Visualise comparisons between different options (highlight variations)
• Support arguments
• Support interdisciplinary work
• What is a GIS not able to do ?• Define the problems/tasks for the user• Ensure suitability of the chosen data and process model• Guarantee that the results make sense• To prevent the user from choosing a theoretically correct but too
expensive/complicated option
Reference: N. Bartelme, 1995
Summ
ary
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 38 -
• Geographic information (GI) has a spatial relation• GI has huge, heterogeneous data volumes
• from MByte to TByte• from relational tables to special data types (BLOB, BULK, LONG,
Geometries etc.)• GI serves an interdisciplinary field of users• GI has a long life-span with high demand on storage and security• GI is expensive to acquire and manage• GI usually demands a graphic (cartographic) representation
„What‘s Special About Spatial?“
Summ
ary
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 20
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 39 -
GIS Literature – a selection in English
• Burrough. P., McDonnell, R. (1998): Principles of Geographical Information Systems, Paperback: 356 pages, Oxford University Press, USA; 2 edition, ISBN-10: 0198233655, Price 69$
• Demers, M. (2002):Fundamentals of Geographical Information Systems, 2nd Edition. London: John Wiley & Sons. Inc, 656 pages, ISBN: 0-471-42609-1 price: 92,95$
• Bernhardsen, T. (2002)Geographical information Systems. An Introduction, 3rd Edition. London: John Wiley & Sons. Inc, 408 pages ISBN: 0471 41968 0, Price: 70 $
Literature
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 40 -
Basic literature – course reference (in German)
• Bill, R. (1999): Grundlagen der Geo-Informationssysteme, Band 1: Hardware, Software und Daten, Wichmann Verlag Heidelberg, 4. edition, 454 pages.
• Bill, R. (1999): Grundlagen der Geo-Informationssysteme, Band 2: Analysen, Anwendungen und neue Ent-wicklungen, Wichmann Verlag Heidelberg, 2. edition, 475 pages.
Literature
Prof. Dr.-Ing. Ralf Bill GI Basics
Introduction to GIS 21
Rostock University, Chair for Geodesy and Geoinformatics GI_Basics - 41 -