Unit 1 What is GIS1 Unit 1 What is GIS UNIT 1 What is a GIS Unit 1 What is GIS 1.1 Maps Definition of a map A map is a graphic form, normally to scale, of spatial abstraction of features

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Unit 1 What is GIS

UNIT 1What is a GIS

Unit 1 What is GIS

1.1 MapsDefinition of a map

A map is a graphic form, normally to scale, of spatial abstraction of features on, or in relation to, the surface of the Earth.

Types of mapsTopographic maps and thematic mapsTopographic map: A reference tool, showing the outlines of selected natural and man-made features of the Earth. "Topography" refers to the shape of the surface, represented by contours and/or shading, but topographic maps also show roads and other prominent features. Thematic map: A tool to communicate geographical concepts such as: the distribution of population densities, climate, movement of goods, land use etc. Line maps versus photo (image) maps 2D vs 3D maps

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Unit 1 What is GIS

Characteristics of maps Scale The scale of a map is the ratio between distances on the map and corresponding distances in the real world, e.g., if a map has a scale of 1:50,000, then 1 cm on the map equals 50,000 cm or 0.5 km on the Earth's surface "Small scale" and "large scale" is often confused, e.g, 1:50,000 vs. 1:500,000The scale controls not only how features are shown, but what features are shown, e.g., Engineering building: 0.2mm*50,000=10 m

Map projections The Earth's surface is curved but as it must be shown on a flat sheet, some distortion is inevitable A projection is a method by which the curved surface of the earth is represented on a flat surface Numerous projections have been invented for various applications (best projection ?)

Cartographic abstraction Selection of the few features in the real world to include Classification of selected features into groups (e.g., bridges, churches, railways) Simplification of jagged lines (e.g., coastlines)Exaggeration of features to be included that are to small to show at the scale of the map Symbolization to represent the different classes of features chosen

Unit 1 What is GIS

Geographic (Geospatial) information

Information about places on the earth’s surfaceKnowledge about where something isKnowledge about what is at a given locationCan be very detailed or very coarseOften relatively staticCan be very voluminous

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Unit 1 What is GIS

1.2 Basic Concept of a GIS

GIS can be considered as a map information system for management, analysis, presentation and distribution.

DatabaseStorage

Management

Presentation

ManipulationAnalysis

Distribution

Maps

Unit 1 What is GIS

data collection

Data Sources

Data Management

Analysis

Real World

Users

data retrieval,manipulation

data input

takeaction

informationfor decisionmaking

GIS Workflow

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Unit 1 What is GIS

GIS is a location based information system: A GIS stores information about the world as a collection of layers that can be linked together by geography.

Layer/Theme !

Unit 1 What is GIS

Why themes (layers)?Logical breakdown of data - related objects in each themeAssemble maps for different purposesby combining themesExamine interaction between themesCreate new themes*Paper maps use symbolism to distinguish between layers, to compensate for the limitations of the technology

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Unit 1 What is GIS

Alternative NamesGeospatial (Spatial) Information SystemGeographic(al) Information SystemLand Information SystemEnvironmental Information SystemAutomated Mapping/Facilities ManagementGeographical Information Sciences (GIScience) Geographical Information Services (GIServices)Desktop Mapping

Unit 1 What is GIS

The Academic Definition

"A system of hardware, software, data, people, organizations and institutional arrangements for collecting, storing, analyzing, and disseminating information about areas of the earth." (Dueker & Kjerne, 1989)

Tao’s DefinitionA GIS is a computer-based information system for collection, management, manipulation, analysis, presentation, and dissemination of geospatially referenced data.

Definition of a GIS ?

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Unit 1 What is GIS

A Mathematical DefinitionMeasure aspects of geographic phenomena and processes; Represent these measurements in the form of a computer database;

Operate these representations to produce more measurements and to discover new relationships;

Transform these representations to conform to other frameworks of entities and relationships.

RR OO TTMM

Definition of a GIS ?

Unit 1 What is GIS

H a r d w a r eS o f t w a r eD a t aP e o p l eM e t h o d s

1.3 Components of a GIS

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Unit 1 What is GIS

HardwareComputers (PC, workstations, servers)

CPU, Pentium 4 2.5GHz ? Memory, 8GB ? Storage devices (Mass storage)

Hard disks, Tape (4mm, 8mm 8GBs), Optical disks (>1GB, $100 per Disk), CD –ROM (640MB, $1-2 per CD)/DVDZip drivers (100-200MB, $20 per disk), Jazz-drivers (1G, $50 per disk), Flash cards, USB HD

Input devicesKeyboard, Scanner, Digitizer, Camera, Voice recognitionGPS, stereo plotter, remote sensing sensors

Output devicesGraphics monitors (graphics cards)Printers (dot matrix/Laser/Inkjet): dpi ?Plotter (Drum/Flatbed)

Communication/networking devicesWAN/LAN/High-Speed NetworkModem/Phone Lines/CableAs the Internet evolves, its data transfer rate is increasing very quickly. From the first level(CA-1, 10MB/s), to the second(CA-2, 150MB/s), to the third(CA-3, 10GB/s), and beyond.

Unit 1 What is GIS

SoftwareOperating systems

Windows/UNIX/LINUXBasic GIS software

ESRI: ArcGIS, ArcInfo, ArcViewIntergraph: Geomedia, MGEAuto Desk: AutoCAD Map, MapGuideMapInfo: MapInfoBently: MicrostationPCI Geomatica (PANMAP, SPANS)Caris

Data Base Management Systems (DBMS)Oracle, DB2, Informix, Sybase, Microsoft SQL, Access

Development languagesCommon programming languages: VC, VB, Java, FortranMicro Language: not exist anymore( e.g., Avenue: Arcview, MapBasics: Mapinfo, AML, MDL: Microstation)

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Unit 1 What is GIS

Data

Spatial dataE.g., Coordinates, location of a well, boundaries, road networks

Non-spatial data (attributes, aspatial data)E.g., Land ownership, address, population densities, soil PH values

Data relationships (spatial relationship-topology, attribute relations)Temporal dataMetadata (data about data)

Unit 1 What is GIS

Spatial data

Objects or entities that are referenced by their location

Latitude / longitude coordinatesx / y coordinatesStreet addressAdministrative unit

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Unit 1 What is GIS

Attribute data

Data that are linked to the spatial objectsCensus data by administrative unitLand parcel ownership recordsSoil or vegetation characteristicsHealth records by medical centerRoad quality information

Unit 1 What is GIS

Id Pop Avg Exp

305 20,838 5,934

306 74,293 21,893

... ... ...

Id Type Staff

156 RPH 17

157 General 47

... ... ...

305

306304

303

302

154 156

157

160

155

158159

Census districts

Hospitals

Attribute relations

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Unit 1 What is GIS

Traditionally information is organized in lists, maps add information about the “where” of the data

Data Relations

Unit 1 What is GIS

Exploring Relationships

Based on geographic location and proximity, GIS makes connections between activities

Looking at data geographically can often suggest new insights, explanationsThese connections are often unrecognized without GIS, but can be vital to understanding and managing activities and resourcesE.g., we can link pollution sources with disease patterns

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Unit 1 What is GIS

Pollution Sources Leukemia Cases

Combining data sets

Unit 1 What is GIS

Information about “where” allows us to combine heterogeneous data sets

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Unit 1 What is GIS

Methodology and People

MethodologyGIS expertise and knowledge

PeopleProblem solving skillsTeam skillsCommunication skillsManagement skills

Unit 1 What is GIS

Which is the most costly component in a GIS?

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Unit 1 What is GIS

1. 4 Functional Requirements for A GIS

Data input Existing maps, field observations, aerial photographs, sensors (airborne and satellites)

Data storage and managementData processing and analysisData output and presentation

Maps/tables/figures/video/audio/3D modelsVarious interaction techniques: mouse, keyboard, Voice, 3D mouse, VR (view, voice, motion, tasting, smelling)

Unit 1 What is GIS

GIS Capabilities

Data capture/input:Input data by digitizing, scanning, or direct coordinate entryEdit data in the GIS to correct errors or add featuresLabel the spatial features so they can be identified (names or codes)

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Unit 1 What is GIS

GIS Capabilities

Management:Link attribute data to spatial objectsLink to external databasesMake changes in existing databasesUpdate database featuresImport and export from/to other GIS or DBMSCombine map sheets to create large databases

match the edges of neighboring map sheets

Unit 1 What is GIS

GIS Capabilities

Manipulation:Make maps from different sources compatible so that they can be drawn on top of each otherTransformation of coordinates Projection change

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Unit 1 What is GIS

GIS Capabilities

Analysis: Query

Select features by their attributes: “find all districts with literacy rates < 60%”Select features by geographic relationships: “find all family planning clinics within this district”Combined attributes/geographic queries: “find all villages within 10km of a health facility that have high child mortality”

Unit 1 What is GIS

GIS Capabilities

Analysis (cont.):Buffer: find all settlements that are more than 10km from a health clinicPoint-in-polygon operations: identify for all villages into which vegetation zone they fallPolygon overlay: combine administrative records with health district dataGeocoding/address matching: match an address list with a street mapNetwork operations: find the shortest route from village to hospital

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Unit 1 What is GIS

GIS Capabilities

Modeling: identify or predict a process that has created or will create a certain spatial pattern

Diffusion: how is the epidemic spreading in the province?Interaction: where do people migrate to?What-if scenarios: if the dam is built, how many people will be displaced?

Unit 1 What is GIS

GIS Capabilities

Display/output:Exploratory

visualize pattern and identify anomalies compare information in map space and data space

Cartographyproduce high quality map output for publicationcreate a digital or paper census atlas

Export map output to other packages

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Unit 1 What is GIS

1.5 An Example of GIS

Site selection

Unit 1 What is GIS

How does a GIS Work ?

ABC GIS Consulting CompanyContract No. 2000

“Site Selection for a new Varsity Community Center”

The following criteria specified by the development agency:

1. within 2km of Yorkdale Shopping Centre2. within 1km of Yong Street3. on slopes of less than 2 degree4. on land of Agricultural Grade III

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Unit 1 What is GIS

How does a GIS Work ?

Data CollectingData Assembling

STEP 1

Topographic map

Landuse map

DTM

Unit 1 What is GIS

How does a GIS Work ?

STEP 2 Data Analyzing

Landuse

DTM

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Unit 1 What is GIS

How does a GIS Work ?

STEP 3Data AnalyzingData Displaying

New Community Center

Unit 1 What is GIS

1.6 GIS Applications

City planning (phone, cable, gas, electricity, vegetation cover, sewage supply, transportation, etc)Natural resource management (forest, land, water, animal – hazards, erosion, pollution…)Transportations (GPS navigation)Business geographics (store location, Wal-Mart) Location based services (L-commerce, M-commerce)

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Unit 1 What is GIS

Application AreasUtilitiesMarketingTransportationUrban / Cadastre Health provisionEpidemiologyDemographyEmergency responseSocial sciences and humanities

Natural Resources ManagementEcologyClimatologyGlobal change researchOceanographyFamine early warningNavigationAgriculture……….

Unit 1 What is GIS

1.7 SummaryReadings (must)

Tor Bernhardsen, Chapter 1 and 2Web readings (must)

Digital earth (Al Gore) http://opengis.org/info/pubaffairs/ALGORE.htmThe GIS Primer: www.innovativegis.com/education/primer/primer.html

Additional readings (optional)Geographic Information Systems as an Integrating Technology: Context, Concepts, and Definitions: http://wwwhost.cc.utexas.edu/ftp/pub/grg/gcraft/notes/intro/intro.html

AssignmentsDesign a map showing the population densities of GTA?Describe at least two GIS applications in campus (list all the functions that can be supported by a GIS), e.g., (a) student housing GIS which would help students to find appropriate rental properties. (b) design of a campus GIS which would help to remove physical and educational barriers which exist for university students with disabilities.Prepare a class presentation of a GIS application example (2 min)

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Unit 1 What is GIS

Origins of GISAdvances in computing, cartography and photogrammetry --> automated GIS in 1960sIan McHarg published “Design with Nature” in 1969

formalized concept of land suitability/capability analysis

Harvard Laboratory for Computer Graphicsdev. & made avail. series of automated mapping & analysis prog.

1st GIS: Canada Geographic Information System (CGIS)Roger Tomlinson, 1960s, rehabilitation & dev. of Canada’s agricultural lands

1970s commercial development -> ESRI

Unit 1 What is GIS

Origins of GIS

Cartography: automated mapping, map algebraRemote sensing: raster image processingComputer science: database management systemsGeography: spatial analysis