12.1 Review 12.1 Review 12.2 Outlook

(1)

12 Review and Outlook

12.1 Review 12.1 Review 12.2 Outlook

http://www-kdd.isti.cnr.it/NWA

(2)

12.1 Review

• What are the basic functions of a geographic

• What are the basic functions of a geographic information system?

Functional Components

Spatial Data Collection of

Spatial Data

Functional Components Structural Components

Visualization,

Spatial Data Management Spatial Data

Analysis,

• What are some common names for GIS in

Cartography Modelling

• What are some common names for GIS in

diverse areas?

(3)

12.1 Review

• What are spatial objects?

http://worboys.duckham.org/

• What are the two main distinctions of spatial objects on basis of their contour?

objects on basis of their contour?

www.maps.google.de www.wetteronline.de

(4)

12.1 Review

• What are the two main

^Framework^Spatial ^Domain^Object

• What are the two main models of space?

• What are the basic concepts

Framework

spatial field

Domain

spatial reference

• What are the basic concepts of geometry and topology?

^Attribute^Domain

field

Spatial Embedding reference

of geometry and topology?

• What are the main

topological

relationships?

(5)

12.1 Review

• What are the characteristics of the raster model?

• What are the main compression techniques for raster geometry?

raster geometry?

(6)

12.1 Review

• What are the characteristics of the vector model?

• What problems arise during discretization?

(7)

12.1 Review

• Which methods for rasterization of

• Which methods for rasterization of vector shapes are there?

?

1 3

2 2 1

?

• Which methods for vectorization of raster shapes

21

• Which methods for vectorization of raster shapes are there?

are there?

(8)

12.1 Review

• What are the main topology models for vector

• What are the main topology models for vector geometry?

• Which interpolation

• Which interpolation methods for fields

methods for fields are there?

//skagit.meas.ncsu.edu/~helena/gmslab/interp/

(9)

12.1 Review

• How to intersect vector geometry segments

efficiently?

a₁ a₃

e₂

e₄ x₁

a a₂

e₁

e₃ e₂

S S

x₁, e₃, e₂, a₄, e₄

Q (events):

T (active segments):

• Which

a₄ S_2,S₃

T (active segments):

• Which

operations on operations on fields are there?

http://worboys.duckham.org/

(10)

12.1 Review

• What is a (thematic or

• What is a (thematic or topographical) map?

• Which means for designing maps are there?

http://www.lung.mv-regierung.de/

http://www.mscgis.info/

• Which means for designing maps are there?

(11)

12.1 Review

• Why cartographic generalization

• Why cartographic generalization is necessary at all?

• What are the basic operations

• What are the basic operations of generalization?

http://maps.google.de/

of generalization?

(12)

12.1 Review

• How polylines can

• How polylines can be smoothed?

• How does the

• How does the Douglas/Peucker Douglas/Peucker algorithm work?

• Why the Douglas/Peucker algorithm does not

• Why the Douglas/Peucker algorithm does not preserve right angles?

http://en.wiki.mcneel.com/

(13)

12.1 Review

• What procedures exist for the transition from

• What procedures exist for the transition from polygons to lines?

• What is the challenge in the

• What is the challenge in the placement of text?

placement of text?

http://upload.wikimedia.org/

(14)

12.1 Review

• Is it possible to evacuate spatial queries with core

• Is it possible to evacuate spatial queries with core SQL?

• On which level SQL is extended in order to become spatial SQL?

become spatial SQL?

(15)

12.1 Review

• How to formulate with spatial SQL the query

"Through which parcels do brooks flow"?

• What are the main differences between Oracle Spatial and Postgres?

Spatial and Postgres?

(16)

12.1 Review

• What are the two steps in

• What are the two steps in the evaluation of spatial queries?

queries?

• What are the differences

• What are the differences between conservative and progressive approximations?

progressive approximations?

http://dbs.mathematik.uni-marburg.de/teaching http://dbs.mathematik.uni-marburg.de/teaching

(17)

12.1 Review

• Can conventional B/B+-trees be used for indexing

• Can conventional B/B+-trees be used for indexing spatial data?

• How points in the plane are ordered according to

• How points in the plane are ordered according to the Z-order?

the Z-order?

• How good is the Z-order as a spatial index?

a spatial index?

(18)

12.1 Review

• How does the data-driven point quadtree work?

A D E

I

11 17

C

F

E J I A

C B

F H J I

K

10 20

21 20 23

9 5

15

C

E J I

B G

J

8 23

2 19

24 14 15

6

19 18 4

8

A B

D G K H

• How does the R-tree work?

a

c e

g j

B I I II

b

c g

f

h i

j

A

II D I II

A B C D

C d

a c f e g j b d h i

(19)

12.1 Review

• When does the R-tree become increasingly

• When does the R-tree become increasingly inefficient as index structure?

• How in principle does the linear split method

• How in principle does the linear split method work with the R-tree?

work with the R-tree?

e

m 9

e 3,5

g

3,5

g 2

j 2

11

(20)

12.1 Review

• What are the characteristics of the K-d tree?

• What are the characteristics of the BSP tree?

• What are the characteristics of the Grid File?

(21)

12.1 Review

• For what purpose XML can be used?

• What are the main components of a document type definition (DTD)?

type definition (DTD)?

(22)

12.1 Review

• What concepts to integrating different XML

• What concepts to integrating different XML documents are there?

• What are the advantages

• What are the advantages of XML schema in

of XML schema in contrast to DTDs?

http://www.jeckle.de/

(23)

12.1 Review

• For what purpose GML can be used?

• What are the characteristics of XSLT?

• What are some important SVG commands?

(24)

12.1 Review

• What are the special features of the combination

• What are the special features of the combination of Postgres and JDBC?

/**

* @param c PGpoint describing

* the circle’s center

* @param r radius of circle

*/

public PGcircle(PGpoint c, double r) public PGcircle(PGpoint c, double r) {

this();

this.center = c;

this.radius = r;

}

(25)

12.1 Review

• What are the special features of the combination

• What are the special features of the combination of Oracle Spatial and JDBC?

• How GML based data can be processed with Java?

http://www.geo.unizh.ch/

http://www.xml.com/

(26)

12.1 Review

• Which are the architectures of geographic

• Which are the architectures of geographic information systems?

• What are the typical functions of a functions of a

GIS client (GIS server)?

(GIS server)?

http://www.it-infothek.de/

(27)

12.1 Review

• How photogrammetry can

• How photogrammetry can be characterized?

• Which kinds of scanner are

• Which kinds of scanner are used in Earth exploration

used in Earth exploration satellites?

• How does LIDAR work?

http://www.uni-potsdam.de/.../febasis/febasis06_04-1206.pdf

• How does LIDAR work?

http://publik.tuwien.ac.at/files/PubDat_166922.pdf

(28)

12.1 Review

• What are the typical geometric

• What are the typical geometric errors in photographic systems?

reference plane invisible space invisible space

http://homepage.univie.ac.at/.../lba_fe_28102004.pdf

• What are the elements of

side view http://homepage.univie.ac.at/.../lba_fe_28102004.pdf

elements of image

interpretation?

(29)

12.1 Review

• How can environmental data be

• How can environmental data be characterized?

• What are the properties of

• What are the properties of monitoring

monitoring networks?

http://www.wald-online-bw.de/

aus: http://www.wsl.ch/

(30)

12.2 Outlook

• Location Based Services (LBS) are services,

– That are accessible with mobile devices through the mobile network

mobile network

– Integrating a mobile’s device location with other

information so as to provide added value to the user information so as to provide added value to the user

• Classification of LBS applications

– Person-oriented – Person-oriented

• Person located can control the service

– Device-oriented – Device-oriented

• Person or object located is not controlling the service

controlling the service

www.m3-systems.com/en/projects.php

(31)

12.2 Outlook

• Types of application design

– Pull Services

Request

– Push Services

Response

– Push Services

Event Data transfer

(32)

12.2 Outlook

• Application areas

– Travel services

• Routing, city, hotel and restaurant guides

– Emergency

• Locating a person in need, warn persons in danger

– Fleet management – Fleet management – Phone tracker

• Child watch, anti-theft tracking

– Friend finder, blind dating – Mobile phone tariffs

– Mobile phone tariffs

http://sourceforge.net/dbimage.php?id=132227

(33)

12.2 Outlook

• Self-locating: User (his mobile device) locates himself

– Global Positioning System (GPS) – Manual position input (not smart) – Manual position input (not smart)

• External locating: Operator locates the user’s mobile device

device

– Determining the current mobile network cell – Signal comparison between three adjacent cells – Signal comparison between three adjacent cells

• Locating provided by third parties, mobile device involved

mobile device involved

– Location transponder

– Peer-to-Peer locating

(34)

12.2 Outlook

• Global Positioning System (GPS)

– Enables three dimensional positioning near the earth – Measuring the runtime of signals between the satellite – Measuring the runtime of signals between the satellite and the GPS-receiver, from which the distance and the position can be deduced (trilateration).

position can be deduced (trilateration).

– The transmitted signal describes a circular sphere centered at the a circular sphere centered at the satellite on which surface the

signal is received at the same signal is received at the same time → circular baseline of equal receiving times

on earth on earth

http://www.uni-giessen.de/ilr/frede/

(35)

12.2 Outlook

– From the intersection of baselines of (at least) three – From the intersection of baselines of (at least) three

satellites the position on the earths surface is deduced – Prerequisite is the temporal coordination of the

– Prerequisite is the temporal coordination of the satellites and the receiver,

otherwise the baseline of a

fourth satellite is needed

(36)

12.2 Outlook

– Control segment – Control segment

• Passive ground stations to track the flight paths of the satellites

satellites

4 monitoring stations operated by the U.S. air force

since end of 2005 6 more stations operated by the NGA (National Geospatial-Intelligence Agency)

Geospatial-Intelligence Agency)

one "Master Control Station" for evaluation

• Every satellite can

• Every satellite can always be received by at least two

by at least two

ground stations

(37)

12.2 Outlook

– GPS-receiver – GPS-receiver

• Composed of an antenna, receiver-processors, and a highly- stable clock

stable clock

• May also include a display for providing location and speed information

information

• Dedicated devices or integrated into cars, mobile phones,

mobile phones, watches, etc.

http://www.connect.de/.../Bluetooth- http://images.fuzing.com/.../

www.ecvv.com/product/1233023.html

(38)

12.2 Outlook

• Cell of Origin COO

– Every cell belongs to one base station

station

– Different frequencies are used in neighbouring cells

in neighbouring cells

– Base stations know about mobile phones within their cell

– Accuracy of the position

depends on the size of the cell

(39)

12.2 Outlook

• Location transponder

– Mobile device gets location information from transponders (e.g. infrared, bluetooth)

transponders (e.g. infrared, bluetooth) – Advantages

• Quite precise: 5-15m

• Able to show user’s orientation

• May send additional information

• Suitable for indoor applications

– Disadvantages

• Mobile device needs additional software

• Transponders have to cover the whole area

• Synchronization of transponders and applications is necessary

(40)

12.2 Outlook

• Example: “Balise”

– Data is transmitted while the train passes over the

“Balise” (transponder principle)

• Some “Balisen”send always the same information

• Others are controlled by so-called

• Others are controlled by so-called Lineside Equipment Units (LEU)

– Receiver in the train: Balise – Receiver in the train: Balise

Transmission Module (BTM)

– Components of the European Train – Components of the European Train

Control System (ETCS)

(41)

12.2 Outlook

• Peer-to-peer positioning

– Exchange of position information between mobile devices

devices

– Advantages

Decentralized position

• Decentralized position information acquisition

• Position information

from specialized devices

– Disadvantages – Disadvantages

• Quality of information unknown

• No standardized peer-to-peer system

http://lion.disi.unitn.it/intelligent-optimization/research.html

• No standardized peer-to-peer system

(42)

12.2 Outlook

• Intelligent transportation systems (ITS)

– Automotive navigation systems are a part of ITS – Goals of ITS

– Goals of ITS

• Preserve mobility in view of increased motorization, urbanization and population growth

urbanization and population growth

• Increase road safety

• Minimize congestion and

• Minimize congestion and environmental pollution

– Based on new information technology for simulation, technology for simulation, real-time control, and

communications networks communications networks

http://www.advantech.com.tw/.../Transportation_page2.htm

(43)

12.2 Outlook

• Components of a navigation system

www.ikg.uni-hannover.de

(44)

12.2 Outlook

• Automotive navigation

– Pilotage, recognition of “landmarks“

– Dead reckoning – Dead reckoning

• Previously determined position

• Recordings of the wheel rotation and steering direction

– Inertial navigation systems (INS)

• Initially provided with the car’s position, orientation, and speed

• Recordings of motion and rotation sensors

– Radiolocation – Radiolocation

• Measuring phase and runtime of radiowaves

• Terrestrial (e.g. GSM) or satellite-based (GPS)

(45)

12.2 Outlook

• Map Matching

– Process of aligning a sequence of observed user positions with of observed user positions with the road network on a digital map

map

– Influencing factors

• Accuracy of the positioning

• Systematic error behavior of the used sensors

used sensors

• Quality of the map

http://www.unibw.de/bauv11/geoinformatik/lehre/skri

(46)

12.2 Outlook

• Gazetteer

– Geographical dictionary or directory

• Mapping indirect spatial references to direct ones

→ linking a name (of a location) to its geographical coordinates

coordinates

– Often categorized by the type, and scope, of the information presented

of the information presented

• World gazetteers

• Short-form gazetteers

• Descriptive gazetteers

• Thematic gazetteers

www.sfhs.org.uk/gazetteer.asp

(47)

12.2 Outlook

• Threats to privacy

– Subsequent queries of a user’s location may be used to create a movement profile

to create a movement profile – Tracking of persons

possible (stalking) possible (stalking) – Danger of a

"glassy citizen"

• Data privacy

protection necessary

http://pixelbuy.com/Ebay/Import/GPS%20TK202/google+.jpg

(48)

12.2 Outlook

• Classification of system architectures

– Non-cooperative architecture

• Users depend only on their knowledge to preserve their

• Users depend only on their knowledge to preserve their location privacy

– Centralized trusted party architecture – Centralized trusted party architecture

• A centralized entity is responsible for gathering information and providing the required privacy for each user

and providing the required privacy for each user

– Peer-to-Peer cooperative architecture

• Users collaborate with each other without the interleaving

• Users collaborate with each other without the interleaving of a centralized entity to provide customized privacy for each single user

each single user

(49)

12.2 Outlook

• Non-cooperative architecture

– Landmark objects

• Instead of reporting the exact location,

• Instead of reporting the exact location, report the location of a closest landmark

• The query answer will be based on the landmark

• Voronoi diagrams can be used to identify the closest landmark

http://mdm2007.uni-mannheim.de