GIS III
Fragen zur Vorlesung GIS III an der ETH bei Prof. Raubal Basierend auf der Zusammenfassung von Roland Schenkel. Karten sind ohne Grafiken ohne Interoperabilität
Fragen zur Vorlesung GIS III an der ETH bei Prof. Raubal Basierend auf der Zusammenfassung von Roland Schenkel. Karten sind ohne Grafiken ohne Interoperabilität
Kartei Details
| Karten | 75 |
|---|---|
| Lernende | 11 |
| Sprache | English |
| Kategorie | Informatik |
| Stufe | Universität |
| Erstellt / Aktualisiert | 26.01.2012 / 08.08.2019 |
| Weblink |
https://card2brain.ch/box/gis_iii
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| Einbinden |
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Service model: general
provides a defined service to a defined user community
Service model: stages
1. Who are the users?
2. What decisions do the users need to make and how frequently?
3. What information is needed to support these decisions? (maps, tables answers to queries, sketches,...)
4. What data are needed? (layers, resolution, accuracy, how current,...)
5. What procedures will need to be exectured on the data to create the information? (display map, complex simulation modeling, tools,..)
6. Are the users satisfied?
7. What about long-term maintenance
Discovery model: general
uses GIS to add to body of scientific knowledge (see also data
exploration in geovisualization)
Discovery model: stages
1. Area of science?
2. What is it we do not know?
3. What are the methods? (visual, tabulation, relationships,...)
4. Change the question?
5. Generalize?
6. New Questions?
GIS Architectures: Single user
* ArcGIS: interface customized?
* results communicated to ultimate users
GIS Architectures: Multiple users
* client-server
* Web service
* ArcGIS for Server (http://www.esri.com/software/arcgis/arcgisserver/index.html)
* customized interface (limited functionality, programming required);
Golden Rules of Project Management
o Projects must be completed on time, within budget, and according to quality standards.
o You will be responsible for the work of others. Make sure they are competent.
o Uncertainty of many kinds exists: you have to live with it but agree how much is acceptable
o Have fun doing it and celebrate success!
GI Assets: commercialization
* most software and data is charged-for
* GIS generates large revenues and costs
* Linking data together can generate added value
GI Assets: Goverments
* geoportal of the Swiss Confederation
* US federal government GI is free
* Many voluntary groups do work for free or low cost
* Some other governments expect users to pay for GI
GI Constrraints
o First Law of GIS: You get something for nothing by bringing together GI from different sources and using it in combination.
o People much more expensive than hard/software
o Technical skills necessary for many GIS roles but rarely sufficient for success in GIS/GI ‘business’, Understanding the operating ‘business’ environment crucial to success.
o Problem: Personalization vs. Privacy
Legal issues: general
The law touches everything – be prepared!
There is a geography of the law – it varies. ‘Commerce is global. Law, for the most part, is not’
Legal areas particularly important for GIS:
* Liability
* Intellectual Property Rights
* Information access laws
* Privacy
the Big Questions:
Can GI be treated as (intellectual) property?
YES
the Big Questions:
Can ‘geographical facts’ be protected?:
usually not
the Big Questions:
Should government GI be protected?
Laws vary
the Big Questions:
How to prove theft of GI?
Watermarks, passwords, etc.
the Big Questions:
Who owns GI when new stuff is added?
All Contributors
the Big Questions:
How to price GI?
* By perceived value, not cost
* Exploit economies of scale and scope
* Differentitate prducts (& price) for different markets
* Seize first mover advantage
* user promotions, etc.
WebGIS in Web 2.0?
o Read-write Web
o User-generated content (UGC)
o Bottom-up information flow
o Google Maps, Microsoft Bing Maps, Yahoo Maps, MapQuest
o Rich user experience
o Harnessing of collective intelligence
3-tier-achitectuer
Data tier: Database-server
Logical (middle) tier: Webserver and GIS server
Presentation tier: Client (Browser, desktop, mobile)
Geospatial Web (GeoWeb): definition
Emerging distributed global GIS: widespread distributed collaboration of knowledge
and discovery that promotes and sustains worldwide sharing and interoperability.
Geospatial Web (GeoWeb): enumeration
o Global reach
o Large number of users
o Better cross-platform capability
o Low cost
o Easy to use
o Unified update
o Diverse applications
Types of Geospatial Web Services (selection):
o Map Service: Map= f(map layers, map extent, scale, …)
o Data Access- / Download- / Feature- / Coverage- Service: Geospatial Data = f(filter criteria)
o Gazetteer Services: Geometry= f(geographic name)
o Geocoding Service: Point = f (postal address)
o Catalogue Service: Metadata= f(filter criteria)
Thin vs Thick client: Thin client
* Server performs most of the work
* User does not need to install software
* No powerful client computer needed
* Pressure on GIS server
* Limited user interaction (plain HTML)
Thin vs Thick client: Thick client
* Client performs most functions
* Fast user interaction
* Less pressure on server
* Installation of browser plug-ins / native applications
* Limitations through internet bandwidth & client computing power
Thin vs Thick client: best practice
* Middleway between thin and thick client
* Client performs the operational layers
* Basemap, Query and Analysis made by the server
GeoWeb Services are...
o Open to other software systems over the Web
o Independent of programming language & operating system.
o Self-contained black box with programming interface exposed.
o Loosely coupled with remixing on demand.
o Web service can be consumed by multiple clients, client can consume multiple web services.
o One-for-all release & update.
Geospatial Web Service: functions: Map services
* Allow clients to request maps for specific geographic extent; returned in image format
* Either cached or dynamic
Geospatial Web Service: functions: Data services
* Query, edit, synchronize data over the Web
* Feature editing services
* Search services (for GIS resources)
* Image services (raster)
Geospatial Web Service: functions: Analytical services
* Geocoding services: converting street addresses to geographic coordinates (vs. reverse geocoding)
* Applications: finding customer’s shipping location, finding stop in routing analysis;
Geospatial Web Service: functions: Network Analysis services
Routing, calculating service area, finding closest facility
Geospatial Web Service: functions
* Map services
* Data Services
* Analytical Services
* Network analysis services
* Geometry Services
* Geoprocessing services
* Metadata catalog service
SOAP
* Comunication possibility to bring Information from the Client to the Server.
* Using XML-Files
* needs a big IT infrastructure
* for professional developers
REST
* Comunication possibility to bring Information from the Client to the Server.
* Using parameters in the URL
* fewer standards
* small infrastructure => mass market
* for every user, easy to use
WMS (incl possible operations)
Web Map Service, OGC Standard
* GetCapabilities
* GetMap
* GetFeatureInfo
WFS (incl possible operations)
Web Feature Service
* GetCapabilities
* DescribeFeatureType
* GetFeature
* LockFeature (only for the transactional WFS)
* Transaction (only for the transactional WFS)
WCS (incl possible operations)
Web Coverage Service (for Rasterdata)
* GetCapabilities
* DescribeCoverage
* GetCoverage
CSW
Catalog Service for the Web: Supports publishing & searching geospatial metadata
(read-only & transactional CSW).
OpenLS
OpenGIS Location Services
o Specifies interfaces that enable location-based services (LBS)
o Route service, navigation service, directory service, gateway service, location utility service, presentation service
WPS (incl possible operations)
Web Processing Service
Provides rules for standardizing inputs & outputs for geospatial processing services.
* GetCapabilities
* DescribeProcess
* Execute
