Sample of Questions and Answer Scheme

Introduction to Geographic Information System (GIS)

Course Code: Geog 496

Exercise 1:

Instructor: Dr. M. M. Yagoub

Define GIS

GIS is any computerized information system that is designed to store, manipulate, retrieve, analyze, and display spatially referenced data.

 

 Discuss briefly the history of GIS between 1960 to 2000

•        1963:  Computing comes of age (Establishment of the Urban and Regional Information System Association URISA and  the first GIS Conference in Ottowa, Canada in 1963).

•        1964: Canada GIS-Roger Tomlinson “Father of GIS”

•        1964: Harvard Lab for Computer Graphics and Spatial Analysis

•        1970s GIS software evolves rapidly (more GIS companies appeared e.g. Intergraph, ESRI, Governmental departments introduced GIS e.g. The US Bureau of the Census)

•        1980s GIS software advances significantly (more budget and human resources allocated for GIS, by the end of 1980s more than 4000 GIS/CAD software are introduced)

•        Digital data becomes available (TIGER, World Data Bank, DIME)

•         1990s (integration of Raster and Vector based systems, Multi-media GIS, software become more user friendly)

•        2000:   Web-based GIS

 

What is the difference between automated cartography, CAD, and GIS

GIS - Adds the analytical capabilities (graphic+ attribute) while automated cartography and CAD lack (graphic only)

 

What is the difference between GIS and LIS

Land Information System (LIS) is typical to GIS, but related primarily to large scale and parcel-based system such as Automated Mapping and Facilities Management (AM/FM)

 

List four of the advantages of GIS

·        Time minimization                                 

·        Accuracy improvement  

·        Data can be managed efficiently

·        High cost/benefit ratio

 

 

List the main components of GIS

1.      People

2.       Data

3.      Hardware

4.      Software

5.      Methods

 

 

 

 

Discuss briefly Data “Information” as one component of GIS

·        There are two basic types of map information in a GIS: Spatial and Aspatial (DESCRIPITIVE-attribute)

·        Spatial refers to geographic features that are represented as raster (pixel) or vector (POINTS, LINES, and POLYGONS)

·        Aspatial or Descriptive refers to TABULAR DATA which records characteristics of the geographic features

 

Discuss briefly “People” as one component of GIS

·        People are essential part of GIS

·        Issues related to people are training, education, management, law, security, data sharing and coordination

·        GIS budget (cost of data, hardware, software, and maintenance)

 

Discuss briefly “Hardware” as one component of GIS

·        Input (Keyboard, mouse, light pen, digitizer, scanner, sound)

·        Processing (Central processing unit –CPU-single/multiple)

·        Storage (Magnetic and optical media -Hard disk 4GB, CD-ROM-650MB, Floppy 1.4 MB, Zip 100/250 MB)

·        Output (Screen, LCD projector, sound system, printer, plotter)

 

Discuss briefly “Software” as one component of GIS

·        Operating System (OS) – Windows/NT, UNIX

·        Graphic software (CAD, Microstation)

·        Database software (dBASE, Oracle)

·        Statistical packages (SPSS, SAS, Minitab)

·        Word processing (Ms Word, Word Perfect)

·        Image processing (IDRISI, ER Mapper, ERDAS)

·        GIS systems (Arc/Info, ArcView, MapInfo)

·        Presentation (Ms PowerPoint, SCALA, Coral Draw)

 

 

List Five GIS web sites that you have visited

•       www.gislinx.com      

•       www.gis.com

•       www.geographynetwork.com

•       www.esri.com             

•       www.tandf.co.uk        

•       www.amazon.com 

 

Discuss briefly the impact of the internet on GIS

·        Exchange and Sharing of ideas via- electronic mail (e-mail) and online lists

·        Online forum (video conferencing)

·        Data transfer (File Transfer Protocol- FTP)

·        Browsing (web sites)

 

List five areas of GIS Application

•       Foresters - timber inventory

•       Fire, police, ambulance - 911 and emergency vehicle routing

•       Military - logistics and battle plans

•       Telecommunications - siting cellular transmission towers

•       Local to national scale government - city planning, zoning, natural resources, etc.

•       Academia - used by many other disciplines outside of geography

 

 

  Discuss briefly the  GIS functions

·        Data acquisition (spatial and non-spatial)

·        Data processing (data management)

·        Data analysis (Spatial & statistical analysis)

·        Data storage  (Store  data more efficiently)

·        Data output   (Maps,  graphs, tables, reports)

 

 

Compare between Raster and Vector Model for representing geographic features; illustrate by figures

 

 

Vector Data: Advantages 

•      Data can be represented at its original resolution and form without generalization.

•      Graphic output is usually more aesthetically pleasing (traditional cartographic representation)

•      Since most data, e.g. hard copy maps, is in vector form no data conversion is required.

•      Accurate geographic location of data is maintained.

•      Because it recognizes entities, model allows for efficient encoding of topology, and as a result more  efficient operations that require topological information, e.g. proximity, network analysis.

 

Vector Data: Disadvantages

•      The location of each vertex needs to be stored explicitly

•      For effective analysis, vector data must be converted into a topological structure. This is often  processing intensive and usually requires extensive data cleaning.

•      Topology is static, and any updating or editing of the vector data requires re-building of the topology

•      Algorithms for manipulative and analysis functions are complex and may be processing intensive

•      Often, this inherently limits the functionality for large data sets, e.g.a large number of features.

•      Continuous data, such as elevation data, is not effectively represented in vector form. Usually substantial data generalization or interpolation is required for these data layers

Raster Data: Advantages 

•      Due to the nature of the data storage technique data analysis is usually easy to program and quick to  perform.

•      The inherent nature of raster maps, e.g. one attribute maps, is ideally suited for mathematical modeling and quantitative analysis.

•      Discrete data, e.g. forestry stands, is accommodated equally well as continuous data, e.g. elevation  data, and facilitates the integrating of the two data types.

•      Grid-cell systems are very compatible with raster-based output devices, e.g. electrostatic plotters,  graphic terminals.

•      Also compatible with digital satellite imagery.

 

Raster Data: Disadvantages 

•      The cell size determines the resolution at which the data is represented.

•      Processing of associated attribute data may be cumbersome if large amounts of data exists.

•      Raster maps normally reflect only one attribute or characteristic for an area.

•      Since most input data is in vector form, data must undergo vector-to-raster conversion.

•      Most output maps from grid-cell systems do not conform to high-quality cartographic needs.