Desktop GIS: An Overview

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Desktop GIS An Overview

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Session Objectives

• Objective
• Familiarize students with desktop GIS

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Presentation I Outline

• What is DESKTOP GIS
• Geographic Issues in dealing using Desktop GIS
• How it works
• Data in GIS
• Geographic Inquiry Process and Desktop GIS
• Presenting information
• Using desktop GIS

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1. What is desktop GIS

• ArcGIS Desktop is a collection of software
  products that runs on standard desktop computers.
  
• Desktop GIS allows us to create map for displays
  and presentation by pointing and clicking. In
  Desktop GIS, we can visualize and analyze
  information in new ways, get new insights about
  relationships, patterns, and trends from
  geographic data.
• There are four products in the ArcGIS Desktop
  collection(http//www.esri.com/software/arcgis/abo
  ut/desktop.html)
• ArcReader is a free viewer
• ArcView provides extensive mapping, data use,
  and analysis along with simple editing and
  geoprocessing capabilities.
• ArcEditor includes advanced editing for
  shapefiles and geodatabases
• ArcInfo is the full function, flagship GIS
  desktop.

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2. Geographic Issues in dealing using Desktop GIS

• In geography, as a map is a fundamental tool to
  communicate about space, spatial attributes and
  spatial patterns.
• A paper map uses color, pattern, picture, or
  label to provide us information about features.
  Information on a paper map is limited to what we
  see on it.
• Desktop GIS stores and enables access to all the
  information about map features in a GIS database
  and links the features on the map to the
  information about them.
• In dealing with the geographic information a
  desktop GIS stores information about map features
  (location) and associated descriptive information
  (attribute).
• There are diversity of mapping systems which
  differ on linking location to information, level
  of analysis and access to outside information.

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3. How it works

• Desktop GIS displays features based on their
  attributes.
• Desktop GIS links sets of features and their
  attributes and manages them together in units
  called themes/layers.
• Themes link features with their attributes
• Collections of themes form a GIS database.
• The themes in a GIS database are used to analyze
  multiple situations and solve multiple problems.

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4. Data in GIS

• Maps have spatial (locational) data as well as
  qttributes (non-spatial descriptors) data.
• Data sources can be primary or secondary.
• Primary data are acquired through direct survey
  or measurement.
• Secondary data is acquired through existing
  sources. For example the following are the
  sources of secondary data.
• Census http//www.census.gov/main/www/cen2000.htm
  l
• USGS http//www.usgs.gov/
• EPA http//www.borderecoweb.sdsu.edu/bew/drct_pgs
  /e/enfacts.html
• You can also creating your own data using desktop
  GIS by extracting selected information from the
  existing database.

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5. Geographic Inquiry Processand Desktop GIS

• Geographic inquiry process consists of
• Asking
• Acquiring
• Exploring
• Analyzing and
• Acting
• Desktop GIS helps us perform geographic inquiry.
  Desktop GIS helps you get answers to your
  questions.

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6. Presenting information

• Before presenting information we should know our
  audience.
• We should also decide on the level of detail. How
  many features, How many themes, How many maps are
  to be displayed.
• Organizing and displaying information is both an
  art and science.
• Purpose of presenting information is effective
  communication.
• Desktop GIS helps us prepare for an effective
  communication.

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7. Using desktop GIS

• Using Desktop GIS Involves
• Loading data
• Displaying data
• Identifying map features and displaying their
  attributes
• Changing the way information is displayed
• Performing the analysis
• Evaluating alternatives
• Presenting results