LSD APC Part I WorkshopGeographic Information System

Danny Yeung14 November 2015

Purposes

• To help LSD probationers to prepare for the LSD APC Part I Written Assessment to be held in December 2015.

• To help LSD probationers to recap and/or learn some important terminology, concepts, and practical knowledge of GIS.

Components of GIS

Hardware

Software

DataNetwork

Procedure

People

Components of GIS

Hardware

Software

DataNetwork

Procedure

People

• Client-Server Architecture• Peer-to-Peer Architecture

Types of System Architecture

Reference: “Efficient: Private, Decentralized Networks”, MetaEfficient, http://www.metaefficient.com/privacy/introduction-decentralized-networks.html

• 2 Tiers Web Architecture• 3 Tiers Web Architecture

Web Architecture

Internet

Presentation Tier(Client Tier)

Data Tier(Database Tier)

Middle Tier(Logic/Business/Application Tier)

Database Server& Storage

GIS ServerWeb ServerClient Computer/Device

• Server- Tower server- Rack server- Blade server

• Storage- Direct Attached Storage- Network Attached Storage (NAS)- Storage Area Network (SAN)

Types of Hardware

• Network equipment- Hub- Switch- Router

• Client PC/Workstation

• Printer

• Cloud Computing- Infrastructure as a Service (IaaS)- Platform as a Service (PaaS)- Software as a Service (SaaS)

Types of Hardware

Components of GIS

Hardware

Software

DataNetwork

Procedure

People

• Commercial off-the-shelf (COTS) Software

• Custom Developed Software/Programs

Software

• GIS software• Web server software• Database management software• …

COTS Software

Internet

Database Server& Storage

GIS ServerWeb ServerClient Computer/Device

• Georeferencing• Geocoding• Buffer• Overlay Analysis• Proximity Analysis• Trend Surface Analysis• Hillshading• Shortest Path Analysis• …

Common GIS Software Functionality

Product Vendor % (as of 5/2014)Apache Apache 37.56% IIS Microsoft 33.04% nginx NGINX, Inc. 15.25% GWS Google 2.19%

Web Server Software

Reference: “Web server”, Wikipedia, http://en.wikipedia.org/wiki/Web_server

• 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 Systeme.g. Tamino, DOM-safe

Database Management System

Custom Developed Software /ProgramsServer-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)

Custom Developed Software /ProgramsClient-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

Reference: “Most Popular Coding Languages”, CodeEva, http://blog.codeeval.com/codeevalblog/2015#.VV_yLKPyxaQ=

Custom Developed Software /Programs

Components of GIS

Hardware

Software

DataNetwork

Procedure

People

GIS Data Capture

Reference:“How is a Land Survey Done?” S. Karimi, http://www.dexknows.com/local/home_improvement/guides_and_videos/how-land-survey-done-7153/.“FARO Focus 3D” http://www.faro.com/products/3d-surveying/laser-scanner-faro-focus-3d/case-studies/2014/10/22/vietnam-laser-scanning-encounters-the-ancient-emperors!“Measuring Shoreline Change Along Bays and Oceans Using Historical Aerial Photography and Airborne Topographic LiDAR Surveys ” Bureau of Economic Geology, http://www.beg.utexas.edu/coastal/poster_measuringchange.htm.“Construction Positioning”, Leica Geosystems, http://www.leica-geosystems.com/en/Machine-Control_4677.htm.“Aerial Photographs”, Survey and Mapping Office, http://www.landsd.gov.hk/mapping/en/paper_map/photo.htm

Reference: “What is GIS?”, Indiana Geographic Information Office, http://www.in.gov/gis/gis101.htm

GIS Data

• 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, …

GIS Data Type

• Proprietary formatse.g. IMG, FGDB, Geomedia, …

• Open formatse.g. Geography Markup Language (GML)

- XML-based file format- GeoRSS profile is a type of GML profile- defined by the Open Geospatial Consortium

Data 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)

• X3D• 3DS• 3D MAX• VRML

3D Spatial Data Model Format

• 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

Data Quality

- First Normal Form (1NF)- Second Normal Form (2NF)- Third Normal Form (3NF)- Boyce-Code Normal Form (BCNF)

• 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

Data Model Design

• 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

PerformanceData

Redundancy

Denormalisation

• 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]

Structured Query Language (SQL)

Database ServerGIS Server

SQL

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

Metadata

Components of GIS

Hardware

Software

DataNetwork

Procedure

People

• 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

Network

• 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. 192.125.0.209- IPv6 e.g.2001:0db8:85a3:08d3:1319:8a2e:0370:7344

• Network Port Number:- 20 & 21 for FTP- 80 for HTTP

Network Communication

Components of GIS

Hardware

Software

DataNetwork

Procedure

People

• management aspect of GIS based on well-designed 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.

Procedure

• Open Geospatial Consortium (OGC)- GML- KML- WFS - WMS- CityGML

• World Wide Web Consortium (W3C)- HTML- CSS- HTTP- XML- XQuery

Standards

Components of GIS

Hardware

Software

DataNetwork

Procedure

People

People

• People is the most active component dealing with the design, development, operation, management, and use of GIS.

e.g. GIS SpecialistsGIS ManagersGIS OperatorsGIS End Users

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