gb1 gi basics

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

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Expert system

Binary represen-tation (8Bit)

Legend of map

Knowledge

Gauß-Krüger-Coordinates

Experience

Data basesystem

...011111000100...

Data

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Data, Information, Knowledge

Information system

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Reference: K. Greve, 1995

°CWhat How

WhoWhen

WhereInside what ???

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Information = data + contextInform

ation systems


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




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


'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




Molk. Gie.

GIS is a computer-based system to

• Input,• Manage,• Analyse and• Presentspatial information.

Definition Geographic Information System (GIS) I

IMAP

-

HardwareSoftwareDataUser

I M A P

GIS

-Definition


Definition GIS II = Map + DB in the computer12

1715

14

1251

125

125125

3

2 4

126

1618M

ain street

Map = graphic data Database = attributesBuilding

Parcel xxx

121516

125/1125/3125/2

Main street

Streets

GIS

-Definition

Feature Building- Geometry – Perimeter polygon (x1,y1,.. xn,yn)- Topology – Area, neighbours- Feature ID- Attributes – Owner, # of floors, purpose, value ..- Graphics - black, parallel lines




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

• Mapping Systems/Computer cartography,• Automated Mapping/Facility Management (AM/FM)

• 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

• Mapping Systems/Computer cartography,• Automated Mapping/Facility Management (AM/FM)

History of GISG

IS-D

efinition


Image of the real world

10

x-Street125

Land register

10

125

Tree register

10

125

Supply network

Land usePopulationstatistics

Traffic masterplan

Reports

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaAAAAAAAAAAAAaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

Registers

xxx xxxx xxxxxxx xxxx xxxxxxx xxxx xxxx

125 xxx yyy

Tables

Different views of the real world

One real world – several views

GIS

-Definition




Primary and secondary spatial metrics I

- Coordinates, Construction regulations:

Properties :• Defined metric• Reference system• High accuracy expected• Multidimensional search criteria

64695.740 23685.123 123.76864623.546 23626.876 125.64564593.341 23653.265 122.75664695.740 23685.123 121.752

64695.740 23685.12364623.546 23626.87664593.341 23653.26564695.740 23685.123

x y z

x y

District numbersPostal codes (70000)Telephone book (88)Area codes (0711)Code of municipality

- Code Numbers:

Properties: • Weakly-defined metric • Reference System• Low, variable accuracy• 1-dimensional search criteria

Stuttgart - district numbers

1

3031

40

50

60

61

75

8070

20

Spatialreference


- Names

E.g. Stuttgart city centre

Stuttgart

Stadtmitte

Vaihingen Degerloch

Hedelfingen

Cannstatt

Zuffenhausen

Feuerbach

Primary and secondary spatial metrics II

Glock Manfred

Glock UdoGlocke Eckhard-Gerhard-Karl-JosefGlockenbring Gerhard

Glocker H.-ThomasGlockgether Erika

Glockhaus Kurt

Glockow G ønterGlocza AndreiGloda GabrielGlöble A.

75 Isegrimweg 251 Filder-29

70 Heuweg 9A70 Reginen-44

70 Welfen-66B

1 Schellberg-3450 Einstein-29

1 Herder-9

70 ImAsemwald 28VerlagsVertr.

1 Schøtzen-191 August-76

50 Wilhelma-950 Astweg 1

und M.

244 72 10

6 59 10 2577 92 1577 19 20

4 93 27 112 64 54 55

62 66 2367 91 6976 75 81

14 51 00

72 99 2956 71 90

5 44 11 0166 12 92

- Addresses

City (7000 Stuttgart 1)

Report type: Cable reviewState: February, 3rd 1991District: 1Street : Curve street

Distribution line:4-70014-70024-70504-70604-70704-8002

0.40.40.40.40.40.4

20.9015.8010.9011.5012.5018.10

CUCUCUCUCUAL

Utility Company Stuttgart

Cable # Voltage Length Material

Street names (Keplerstraße 11)

Properties : • Weakly-defined metric• Reference system• Low, variable accuracy• 1 to multidimensional search criteria (text)

- others: e.g. kilometres along roads, waterways,..

Telephone book

Spatialreference




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


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

A-342-2A-342-1

12-1

12-2

Utility mapping125

126

214

215/1

215/2

X-Straße

Real estate/cadaster

X-Straße

Real land use

.....

ReportsUNIVERSITÄT ROSTOCKUmweltwissenschaftliche Fakultät

UnfallberichtOrt: Südring (WHs. 34/3)

Beteiligten: Fahrzeuge HRO 3452 und AC 436

Administration and government

Engineering and planning

Utility and services

Decision makersand citizens

....

Spatialreference




Data in a GIS

Source: http://erg.usgs.gov/isb/pubs/gis_poster/

Contour lines Digital terrain models

Topographic maps Orthophotos

. . . .

. . . .

Data types


Data in a GIS

Source: http://erg.usgs.gov/isb/pubs/gis_poster/

Satellite imagery

Image classifications

Census data

Measurements

. . . .

. . . .

Data types




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


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




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

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dg125 126

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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




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


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




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


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

Polygon BLOB 120.534 270.348 125.00 highway asphalt 120Polygon BLOB 272.128 350.543 122.12 municipal asphalt 60

... ... ... ... ... .... ... ...

Polygon BLOB 654.584 271.156 257.00 highway asphalt 100

Object




One object, several views

• Different geometry: raster/vector

• Different meaning: attributes

• Different status: origin versusprocessed / 2D or 3D

Surveying

…AreaOwnerClasses…

Forestry

…Detailled

classesAgeYear of

afforestation

Biotope mapping

…Plant diversityRecreation characterProtection status…

Data types

Geometry Topology(x1,y1,z1,x2,y2,z2,.. .. ..xn,yn,zn,x1,y1,z1)

(Area - 2-cell, Neighbor cells)

Graphicaldescription

SymbolBorder

Object class : Coniferous forestObject identifier

y

x


Layer model – a more historical model

Settlement areas

Traffic

Land usage

Rain fall

Real world

Natural waters

• Layer = data (objects) + styling rules (appearance)

Data types




From real world to computer model

Real World

Abstraction

Data model Process-based modelLayers FunctionsObject classes ProcessesProperties Analysis

InterpretationPresentation

Visualisation modelSymbols drawing plans regulations

Task

orie

nted

Info

rmat

ion

orie

nted

Data types


From landscape to geoinformation processingLandscapeReal world

Capture

A

B 1234567

GIS

Processing

Visualisation

I

M

A

P

GIS

-Functions




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


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




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


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




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


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




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


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




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


• 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




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$

• Chrisman, N. (2001):Exploring GeographicInformation Systems. 2nd edition. London: John Wiley & Sons. Inc, 320 pages, ISBN: 0471314250 Price: 73,95 $

• Bernhardsen, T. (2002)Geographical information Systems. An Introduction, 3rd Edition. London: John Wiley & Sons. Inc, 408 pages ISBN: 0471 41968 0, Price: 70 $

Literature


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




GIS in the Internet and eLearning-components

• www.gitta.info – a swiss project in English

• http://training.esri.com/gateway/index.cfm - ESRI Training/Education• http://www.gis.com – ESRI Guide to GIS• http://erg.usgs.gov/isb/pubs/gis_poster/ - USGS GIS introduction

GITTA - Geographic Information Technology Training Alliance

Literature