Geographical Information System (GIS) & LBS Augsburg 2019 Anto - - PowerPoint PPT Presentation

Geographical Information System (GIS) & LBS

Augsburg 2019 Anto Aasa

http://aasa.ut.ee/augsburg

Important factors for LBS

• Location
• Spatial data & GIS
• Wireless communication
• Positioning

– Satellite – Mobile phone – Indoor (WLAN, RFID)

• Functioning of LBS (location only is not the

LBS)

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• Everything, what happends in real world has

geographical coordinates

– X – Y – Z – time

• (also in virtual space)

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Location

• Map and database must be in same

coordinate system and datum

– Surface of the earth

• Land
• Sea

– Geoid – Ellipsoid

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Location:

• Describing
• Spatial
• Network

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Spatial databases & GIS

• Location: spatial vs describing?

– N 48° 21’ 17’’ E 11° 47’ 15’’ – Germany, Munich airport

• Relation between points => distances

– Geography in general!!! http://aasa.ut.ee/augsburg

Geographic information system (GIS)

• Mutually related complex of software and

data

– Watching geographical information, – Administration of geographical information, – Analysis of spatial relationships and patterns, – Modelling of spatial processes.

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GIS

• Hardware
• Software
• Database

– Geographical space – Theme (attributes)

• Operations
• Human resource

– Knowledge – Experience

• …

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GIS functions

• Mapping and visualization;
• administration of geographical information;
• data collecting and updating;
• geographical analysis.

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History

• First person who placed different layers on top
• f each other?

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Cholera deaths in London John Snow 1854

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http://aasa.ut.ee/augsburg

History

• 1963: first nation-wide GIS - Canada
• 1966: first raster-GIS
• 1972: first civil use remote sensing satellite Landsat 1
• 1978: first satellites of NAVSTAR (development of GPS technology)
• 1979: first vector-GIS –ODYSSEY GIS
• 1981: Esri ARC/INFO
• 1986: MapInfo – first desktop GIS
• 1994: beginning of standardization of spatial data and infrastructure

(OpenGIS consortium)

• 1996: first Internet based GIS products
• 1996: first Internet based map service MapQuest
• 2000: over 1 million professional GIS users in world, over 5 million

„average“ GIS users

• 2016: starts GNSS Galileo

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Area of use

• Land survey, cartography
• Logistics
• Aviation
• Real estate
• Military forces
• Trade
• Local authority
• Science
• Infrastructure management
• …
• Location Based Services

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Representation of spatial data

• Real world is too complex
• Simplified models

– Maps – Cartography

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Modelling of the real world

• Discrete objects
• Continuous fields

Visualization of invisible objects (Augmented, Mixed Reality)

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Representation of geoinformation in GIS

• objects (set of points, lines and polygons);
• raster;
• attributes.

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Vector

Point Line Polygon

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Raster

slope Elevation shading Population density

• rtophoto

Landuse concentration

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• Attributes table:

– Rows: map objects – Columns: attributes – Queries

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• Layer based model:

– One theme for every layer – One data type for every layer (point, line, polygon, raster)

Elevation

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GIS resolution

http://nas-sites.org/climatemodeling/page_3_2.php

Model vs visualization

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• Use of color

– Traditions of visualising certain object types

• Symbols
• Colors

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• Map scale

– the ratio of a distance on the map to the corresponding distance on the ground (e.g. 1:400 000)

• Generalization

– Simplifying of objects

Measurements accuracy Model accuracy Amount of data

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Generalization

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GIS output

• Table
• Graph
• Report
• Thematic map
• Something else?

What is the aim? Mobile device display!

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Internet maps

• Different API’s for LBS:

– Open Street Map – Google Map – Bing Map

• WMS
• …

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• Earth is not ideal sphere but geoid (potato-

shaped)

– Earth model: ellipsoid

• Map projection – method of representing the

surface of Earth on a plane

– All map projections distort the surface in some fashion

• Error minimization

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Distortions

– area, – direction, – scale, – distance.

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Creating GIS

• Reality model (description of the real world)
• Data model (database structure and

technology)

• Representation model (rules for data

representation)

– e.g. Roads on top of rivers

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Management of spatial data

• Raster model

– Rectangular regular grid of pixels

• Vector model

– Points, lines, polygons (functions determining the shape and form of objects)

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Processing of geographical data

• Processing of the initial data for achievement
• f goals

– Queries (response to relevant conditions) – Spatial analysis (description of place, attribues and relationships between them)

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Quality of spatial data

• Completeness (missing, redundant data)
• Consistence
• Location correctness
• Up-to-date
• Thematic correctness

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For tomorrow

• How to visualize flow in

time and space?

• Movement of parcel
• Data download

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