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Chapter Three: Components of GIS (Part 1)

Chapter Three: Components of GIS (Part 1). 5 Critical Components that GIS Can’t Live Without. A successful GIS has 5 critical components: Hardware Software Data People Methods . Source: http://bgis.sanbi.org/gis-primer/page_12.htm. (a) Hardware & (b) Software. Hardware:

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Chapter Three: Components of GIS (Part 1)

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  1. Chapter Three: Components of GIS (Part 1)

  2. 5 Critical Components that GIS Can’t Live Without • A successful GIS has 5 critical components: • Hardware • Software • Data • People • Methods Source: http://bgis.sanbi.org/gis-primer/page_12.htm

  3. (a) Hardware & (b) Software • Hardware: • Hardware is the computer system on which a GIS operates. Today, GIS runs on a wide range of hardware types, from centralized computer servers to laptops and smart phones used in stand-alone or networked configurations. • Software: • GIS software provides the functions and tools needed to store, analyze, and display geographic information. Source: http://www.iceburghsolutions.com/services/services.htm http://bgis.sanbi.org/gis-primer/page_12.htm

  4. (c) Data  Point – Line – Polygon • Data: • Perhaps the most important component of a GIS. Geographic data and its attributes can be collected in-house, sourced or purchased from data providers. • All geographic features on the earth can be characterized and represented as one of three basic feature types  points, lines, and polygons: Points Polygons Points Lines Lines Polygons Source: http://www.gisdevelopment.net/technology/gis/techgi0047a.htm http://bgis.sanbi.org/gis-primer/page_12.htm http://en.wikipedia.org/wiki/GIS_file_formats

  5. (c) Data  Point – Line – Polygon • Points are used to represent single location feature like a tree, a fire pump, a lamp post, a bus stop, a taxi stand, a monument…etc. A point can also be displayed as a symbol. • Lines are used to represent linear features like rivers, roads, canals, drainages, water pipes, gas pipes, networks…etc. • Polygons are used to represent enclosures or areas like lakes, boundaries, building footprints, flooded areas, contaminated areas, reservoirs, forested areas, nature reserves…etc. Source: http://newsletter.flatworldknowledge.com/ http://lemonprogis.com/what-are-gis-data-types/

  6. (c) Data  Point – Line – Polygon • Please do note that under different map scale, feature type of certain features may change to represent the real world better. Aljunied MRT station is displayed as a polygon in scale 1:1000 Aljunied MRT station is displayed as a point (represented by a MRT symbol) in scale 1:20,000 Source: http://www.onemap.sg/

  7. Geo-Brain Tickler 4: • Choose the most appropriate feature type (point, line or polygon?) for features listed below under the designated scale :

  8. Geo-Brain Tickler 4: The Answer • Choose the most appropriate feature type (point, line or polygon?) for features listed below under the designated scale : • √ • √ • √ • √ • √ • √ • √ • √ • √ • √

  9. Getting to Know GIS Better! Did you get all the answers correct…? No worries! As you explore more about GIS in this e-Learning section, you definitely understand more.  Let’s move on to the next chapter to continue our learning journey…

  10. Chapter Three: Components of GIS (Part 2)

  11. (c) Data  Vector Format Let’s continue with the third component of GIS  Data: Each feature type can be displayed in both two types of data formats/structures  Vector & Raster: • In vector format: • Each feature is composed by a vertex or vertices. Each vertex consists of a pair of X and Y coordinate. • Point features are defined by one coordinate pair – a vertex. • Line features are defined by a string of vertices – also known as an “arc”. • Polygonal features are defined by a set of closed coordinate pairs. • Vectors are best suited to represent features that have distinct boundaries or limits that are discrete in space and time, e.g. buildings, parks or roads. • Discrete data is helpful in showing exact location, perimeter, and length of objects. Source: http://bgis.sanbi.org/gis-primer/page_07.htm http://bgis.sanbi.org/gis-primer/page_15.htm http://www.geo.hunter.cuny.edu/~rdatta/gis2/lectures/Lecture2/lecture2.htm http://usgin.org/content/rasters-and-vectors-comparison http://wiki.gis.com/wiki/index.php/Discrete_and_Continuous_Data

  12. (c) Data  Raster Format • In raster format : • A raster consists of a matrix of cells (or pixels) organized into rows and columns (or a grid). Each cell contains a value representing information of the feature being represented. • Rasters represent points by a single cell, lines by sequences of neighbouring cells and polygons/areas by collections of contiguous cells. • Rasters are best suited to representing continuous data  geographic phenomena that do not have well-defined boundaries and are found everywhere throughout the mapped area. • Continuous data are often shown in a colour scale in order to show change over an extent, e.g. temperature across a region. Source: http://www.geo.hunter.cuny.edu/~rdatta/gis2/lectures/Lecture2/lecture2.htm http://webhelp.esri.com/arcgisdesktop/9.2/index.cfm?TopicName=What_is_raster_data%3F http://www.satimagingcorp.com/gallery/ikonos-singapore-lg.html http://usgin.org/content/rasters-and-vectors-comparison http://wiki.gis.com/wiki/index.php/Discrete_and_Continuous_Data Cells / Pixels

  13. Geo-Brain Tickler 5: • Choose the most appropriate data format (vector or raster?) for each of the situation encountered below:

  14. Geo-Brain Tickler 5: The Answer • Choose the most appropriate data format (vector or raster?) for each of the situation encountered below: • Temperature is continuous – no fixed perimeters • √ • Playground is discrete in nature with exact perimeter & distinct location • √ • Rainfall is continuous – its volume gradually increases or decreases • √ • Building compound is discrete in nature – exact perimeter is possible • √ • Air quality is continuous – air particles have no fixed location • √ • Earth surface or terrain is continuous – it either elevates or descends gradually • √ • Roads and water bodies are discrete – exact perimeter is possible • √

  15. (d) People • People: • GIS is pointless without the people who manage, analyse and map out geospatial data to resolve real world problems. • People who are specialized in GIS can be designated as GIS specialist, geospatial consultant, GIS manager and others, though not really common in Singapore. Source: http://www.cadalyst.com http://flowergarden.noaa.gov http://www.gaaged.org

  16. (e) Methods • Methods: • A successful GIS operates according to a well-designed implementation plan and procedures, which are the models and operating practices unique to each organization. Source: http://bgis.sanbi.org/gis-primer/page_12.htm http://www.esri.com http://www.latitudecartography.co.uk/

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