LSD APC Part I Workshop Geographic Information System. Danny Yeung 6 May 2017

Transcription

1 LSD APC Part I Workshop Geographic Information System Danny Yeung 6 May 2017

2 Purposes To help LSD probationers to prepare for the LSD APC Part I Written Assessment to be held in June To help LSD probationers to recap and/or learn some important terminology, concepts, and practical knowledge of GIS.

3 Components of GIS Procedure Hardware Network People Software Data

4 Components of GIS Hardware

5 Types of System Architecture Client-Server Architecture Peer-to-Peer Architecture Reference: Efficient: Private, Decentralized Networks, MetaEfficient,

6 Web Architecture 2 Tiers Web Architecture 3 Tiers Web Architecture Presentation Tier (Client Tier) Middle Tier (Logic/Business/Application Tier) Data Tier (Database Tier) Client Computer/Device Web Server GIS Server Database Server & Storage

7 Types of Hardware Server - Tower server - Rack server - Blade server Virtual Machine (VM) - Emulation of a computer system Storage - Direct Attached Storage - Network Attached Storage (NAS) - Storage Area Network (SAN)

8 Types of Hardware Network equipment - Hub - Switch - Router Client PC/Workstation - CPU (e.g. Intel Core i7) - RAM (OS dependent) - Graphics Card Printer (resolution, speed, color)

9 Cloud Computing a type of computing that relies on sharing computing resources running in a distributed network Characteristics: - Resource pooling - On-demand self-service - Elasticity - Measured service Deployment Models: - Public cloud - Private cloud - Hybrid cloud Service Models: - Infrastructure as a Service (IaaS) - Platform as a Service (PaaS) - Software as a Service (SaaS) Public Cloud Public Cloud Public Cloud Private Cloud Private Cloud Hybrid Cloud

10 Components of GIS Software

11 Software Commercial off-the-shelf (COTS) Software Custom Developed Software/Programs

12 COTS Software GIS application software Web server software Database management software Client Computer/Device Web Server GIS Server Database Server & Storage

13 Common GIS Application Software Functionality Georeferencing Geocoding Buffer Proximity Analysis Overlay Analysis Trend Surface Analysis Hillshading Shortest Path Analysis

14 Web Server Software Product Vendor % (as of 2/2017) IIS Microsoft 43.16% Apache Apache 20.89% nginx NGINX, Inc % GWS Google 1.03% Reference: Web server, Wikipedia,

15 Database Management System File System Relational Database Management System (RDBMS) e.g. Oracle Database, IBM DB2, Microsoft Access, Microsoft SQL Server Object Oriented Database Management System (OODBMS) e.g. Jasmine, ObjectStore XML Database Management System e.g. Tamino, DOM-safe

16 Custom Developed Software /Programs Server-side Technology ASP (*.asp) ASP.NET (*.aspx) ColdFusion Markup Language (*.cfm) Java via JavaServer Pages (*.jsp) JavaScript using Server-side JavaScript (*.ssjs, *.js) (example: Node.js) Perl CGI (*.cgi, *.ipl, *.pl) PHP (*.php) - Open Source Scripting Python, e.g. via Django (*.py) Ruby, e.g. Ruby on Rails (*.rb, *.rbw)

17 Custom Developed Software /Programs Client-side Technology JavaScript (essentially the client-side scripting languages.) Ajax (Used for implementing JavaScript and XML without effecting the web-page itself) jquery (used as a JavaScript library in which one can easily use commonly used scripts without specifications) ActionScript (used to create animated interactive web applications for Adobe Flash Player using Adobe Flash Pro) FLEX Silverlight

18 Custom Developed Software /Programs Reference: Most Popular Coding Languages, CodeEva,

19 Mapping APIs Mapping Application Program Interface (API) Mapping APIs allow developers to embed maps into webpages using programming interfaces. Selection of mapping APIs for building map applications is often restricted by the application platform and programming language used. - JavaScript API, Android API, ios API, etc. Open-source mapping APIs library: Leaflet, Modest Maps, Polymaps, etc.

20 Components of GIS Data

21 GIS Data Capture Reference: How is a Land Survey Done? S. Karimi, FARO Focus 3D, Hybrid Mobile Laser Mapping System, RIEGL, Construction Positioning, Leica Geosystems, UAV / Drone Training Course, Canadian Unmanned Inc., Landsat 8 Image (Data from USGS), Survey and Mapping Office, Aerial photography, Survey and Mapping Office, TIMMS Indoor Mapping, Trimble,

22 GIS Data Modeling Conceptual Design Reference: What is GIS?, Indiana Geographic Information Office, Logical Design Physical Design

23 GIS Data Type Vector - Point, Line, Polygon - e.g. building, tree, boulder, grave, Raster - Matrix of Pixels Triangulated Irregular Network (TIN) - Delaunay Triangulation Digital Terrain Model (DTM) - contour, spot height, Network - e.g. river/stream, road, pedestrian, railway,

24 Data Model Design Table, Record (Tuple), Attribute, Primary Key Example: TNum LName CID TStamp TCost 2 Chan 1 13: Wong 2 11: Yeung 4 9: Chan 7 15: Leung 8 15: Ng Null 18:02 100

25 Data Model Design Design principle one fact in one place Make use of normalisation to store data without unnecessary data redundancy and avoid update anomalies Normalisation is built around the concept of normal forms - First Normal Form (1NF) - Second Normal Form (2NF) - Third Normal Form (3NF) -

26 Denormalisation Normalisation is not the final solution to database design Performance of the database also needs to be considered In practice, denormalisation may be needed for improving the database performance Data Redundancy Performance

27 Structured Query Language (SQL) a standard query language for relational database management system basic structure of SQL consists of 3 clauses: Select [attribute field] from [relational table] where [condition] SQL GIS Server Database Server

28 Data Format Proprietary formats e.g. ECW, FGDB, Geomedia, Open formats e.g. GML, GeoJSON, Geography Markup Language (GML) - XML-based file format - defined by the Open Geospatial Consortium - GeoRSS profile is a type of GML profile - One of the topographic map formats supported by LandsD in HK

29 3D Spatial Data Model Format KML - is an XML-based file format - focuses on geographic visualization - uses geographic coordinates: longitude, latitude and altitude as its coordinate reference system CityGML - is an XML-based format for storage and exchange of virtual 3D city models - is an application schema for the Geography Markup Language (GML) - supports different levels of detail (LOD) OSGB - mesh model format - the native format of the open source OpenSceneGraph library 3DS, 3D MAX, VRML, X3D, IFC - Industry Foundation Classes - is a open file format for Building Information Modelling (BIM) Data - developed by buildingsmart

30 Data Quality Common topology errors - lines undershoot/overshoot - sliver polygons - duplicate arcs - Topology rules - find dangle node - polygon must not overlap - line must not overlap - Data model design

31 Metadata It is information about the characteristics of geospatial data, such as spatial reference and extent.

32 Network Components of GIS

33 Network Network communications provide the infrastructure to connect GIS operations and support data sharing. Types of Network - LAN (Local Area Network) - WAN (Wide Area Network) - Internet

34 Network Communication Protocol: - File Transfer Protocol (FTP) - Hypertext Transfer Protocol (HTTP) - Remote Desktop Protocol (RDP) - Independent Computing Architecture (ICA) Internet Protocol Address (IP Address): - IPv4 e.g IPv6 e.g.2001:0db8:85a3:08d3:1319:8a2e:0370:7344 Network Port Number: - 20 & 21 for FTP - 80 for HTTP

35 Components of GIS Procedure

36 Procedure management aspect of GIS based on welldesigned implementation plan and business rules to meet organization s objectives and operational needs. implementation plan and business rules are often defined in accordance with best practices, standards, and well known business models.

37 GIS and IT Standards Open Geospatial Consortium (OGC) - GML - KML - WFS - WMS - CityGML World Wide Web Consortium (W3C) - HTML - CSS - HTTP - XML - XQuery

38 Components of GIS People

39 People People is the most active component dealing with the design, development, operation, management, and use of GIS. e.g. GIS Specialists GIS Managers GIS Operators GIS End Users

40 People No GIS can be a success without the right people involved. A real world GIS is actually a complex system of interrelated parts, and at the center of this system is a smart person who understand the whole. Roger Tomlinson Procedure Hardware Network People Software Data

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