Getting to grips with GIS : The technology Dr. Ian Gregory, Department of Geography, University of Portsmouth

Getting to grips with GIS: The technology Dr. Ian Gregory, Department of Geography, University of Portsmouth

Structure of talk • 1. The types of software in GIS • i. Desktop GIS • ii. Attribute database management systems • iii. Spatially-enabled database management systems • iv. Internet GIS • 2. Examples of GIS software • ArcView • TimeMap

Desktop GIS software • The beginning: • ArcInfo • Launched in 1980 by ESRI • Build Arc (GIS functionality) over Info (a RDBMS) • Mainframe-based • Command line driven • Documentat ion 3 feet thick • Set the standards until the mid-1990s

Desktop GIS software (2) • The mid-1990s: • MapInfo: • MapInfo Corporation • Windows-based • Point and click user interface • Intuitive • Moved GIS software into the mainstream • ArcView: • ESRI’s response • Originally just a viewer for ArcInfo • Became (at 3.0) a fully-fledged PC-based GIS software package • ArcInfo: • pcArcInfo – Cut down version of ArcInfo available from the early 1990s • Full ArcInfo – Available under Windows NT by the late 1990s • Retained more functionality than ArcView

Desktop GIS software (3) • Now: • MapInfo still a strong product • ESRI has moved to combine ArcInfo and ArcView into ArcGIS (including ArcInfo 8.0) • TimeMap: • Written by archaeologists at the University of Sydney • Specifically aimed at arts and humanities applications • Temporal functionality but not full GIS • Linked to the ECAI metadata clearinghouse • All the strengths and limitations of free software • Object-orientated GIS • E.g. Smallworld • Use an O-O data model rather than a hybrid GIS data model • Not widely accepted

Desktop GIS software (4) • Costs (academic site licenses through CHEST): • ArcGIS : £3,400 • ArcView: £1,250 • MapInfo: prices vary from £1,000- £2,500 • TimeMap: free (see http://www.timemap.net)

Attribute database management systems • Using a GIS does not require transferring all attribute data into a GIS • Attribute data linked to spatial data through a relational join • Can be accessed through either the GIS software or the host database management system • Examples: • MapInfo: Dbase, Access, Excel, Lotus 123, Oracle • ArcView: Dbase, Access, Excel, Visual FoxPro • ArcInfo: Oracle, Ingres, Dbase

Spatially-enabled database management systems • Spatial extensions to existing DBMSs • Capable of handling spatial data • Eg. point-in-polygon operations • Do not provide full GIS capability • Eg. Vector overlay • Limited mapping capability • Examples: • Oracle Spatial • ArcSDE (ESRI)

Internet GIS • Allows vector GIS data to be disseminated on the web • Clients can: • turn layers off and on • perform spatial and attribute queries • pan, zoom, etc. • Eg. ArcIMS

The ArcView interface The interface is made up of a number of different parts. Menu barButton barTool bar Project window The application window has one project window – it displays the names of all the documents contained in an ArcView project. Document windows For each type of information you work with, there is a document window and interface. Status bar Descriptions of menu choices, tools and buttons appear on the Status bar. Also reports measurements and displays a progress bar for lengthy operations. © ECAI, 2002

ArcView documents Documents are components of a project. Each type has its own window and user interface. View – display, query & analyze themes Table – display attribute data Layout – integrate documents to create presentation-quality maps Chart – represents tabular data graphically Script – program written in Avenue used to customize the interface, automate common functions or create applications © ECAI, 2002

A project is a file for organizing your work. It contains a collection of documents (views, tables, charts, layouts and scripts) that are used to organize information. ArcView projects • Projects organize documents. • All project work is stored in a single file (.apr) that references your data. When you save a project (.apr), it stores the status of the documents it contains, including how and where they are displayed, the current selection sets and the appearance of the application window. You are saving a “snapshot” of the state of ArcView at the time of the save. Views Project window Displays the names of all project documents & acts as a gateway to all documents in the project. In an ArcView session, only one active project at a time. Tables Charts Layouts Scripts © ECAI, 2002

Different themes can reference the same data source. Views and Themes • A theme is a specific way of displaying a data source. • Themes are displayed in views • Each theme has a title and a legend in the view’s Table of Contents Themes The view window has 2 parts – the Table of Contents and the Map Display area. Table of Contents Map Display © ECAI, 2002

Common Theme Operations When a theme is turned on, ArcView draws it in the map display area. Turning off a theme doesn’t delete it! And a theme doesn’t have to be turned on to perform operations on it. • Control visibility • Specify active themes (raised) • Change display order (by dragging) Many operations only work if theme is active. To make more than one theme active, hold down the Shift key as you click on each theme you want to make active. By making a theme active you are telling ArcView that you want to work with the features in that theme. Table of contents draw order is bottom to top – the last theme in the TOC will draw on the bottom (or first in the draw order). © ECAI, 2002

Fill Palette Pen Palette Symbol Window To invoke the Symbol window double click on the symbol patch in the Legend Editor or use the shortcut of CTRL-P when you don’t have the Legend Editor open. A palette is a collection of symbols and colors – all the palettes in ArcView are collectively referred to as the Symbol window. Marker Palette Font Palette Color Palette Palette Manager Use the Palette Manager to load, save, clear, create a default palette or reload the system palette. You can also import an icon file – bitmap format. © ECAI, 2002

Using ArcView’s Help system • Online help • Help for buttons, tools, menus Help button • Help for dialog boxes: F1 key • Help Topics: Contents, Index, Find © ECAI, 2002

TimeMap • The primary purpose of TimeMap is to act as a viewer of GIS data as well as many other types of information. • TimeMap does not have all of the features of a typical geographic information system such as: • Data creating • Data editing • Data analysis • Advanced map display • TimeMap does: • Allow easy visualisation and exploration of datasets • Allow integration of disparate datasets using the ECAI metadata clearinghouse • Provide effective temporal functionality © ECAI, 2002

The Sasanian Empire Website • http://ecai.org/sasanianweb • Provides a text based browser interface for the publication. • Provides access to: • Document "Sasanian Seals from the Collection of the Late Edward Gans, at the University of California, Berkeley" by Guitty Azarpay, Et al © ECAI, 2002

Sasanian Publication in TimeMap • Provides an example of the capabilities of the ECAI system to include • GIS data • Historic maps • Images • Texts in a time and place context © ECAI, 2002

Sasanian Publication in TimeMap • A gazetteer of Sasanian Empire places and their attributes is included with information derived from the Sasanian Empire Map published by Tubinger in Germany. © ECAI, 2002

Sasanian Publication in TimeMap • Five key sites in the Sasanian Empire are presented in a map layer that links to images and descriptions of the sites. © ECAI, 2002

Conclusions • In practice their are only a limited number of GIS software packages available • ArcView/ArcGIS (http://www.esri.com) • MapInfo (http://www.mapinfo.com/) • TimeMap (http://www.timemap.net, see also http://ecai.org) • The learning curve is steep but not unmanageable • Hardware and software costs are significant • Do not be constrained by the tools offered by the software

Getting to grips with GIS : The technology Dr. Ian Gregory, Department of Geography, University of Portsmouth