Transcript GIS: The basics

Getting to grips with
GIS:
The technology
Dr. Ian Gregory,
Department of Geography,
University of Portsmouth
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
Department of Geography
University of Portsmouth
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
Department of Geography
University of Portsmouth
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
Department of Geography
University of Portsmouth
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
Department of Geography
University of Portsmouth
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)
Department of Geography
University of Portsmouth
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
Department of Geography
University of Portsmouth
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)
Department of Geography
University of Portsmouth
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
Department of Geography
University of Portsmouth
The ArcView interface
The interface is made up of a
number of different parts.
Menu bar
Button bar
Tool 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
Department of Geography
University of Portsmouth
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
View
– display, query & analyze themes
– integrate documents to
create presentation-quality maps
Layout
Department of Geography
University of Portsmouth
Documents are components of a project.
Each type has its own window and user
interface.
Table
– represents
tabular data graphically
Chart
– display attribute data
– program written in
Avenue used to customize
the interface, automate
common functions or create
applications
Script
© ECAI, 2002
ArcView projects
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.
 Projects organize documents.
 All project work is stored in a single file (.apr) that references your
data.
Views
Project window
Tables
Charts
Layouts
Scripts
Department of Geography
University of Portsmouth
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.
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.
© ECAI, 2002
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
Different
themes can
reference
the same
data source.
Table of Contents
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University of Portsmouth
Map Display
The view window has 2 parts
– the Table of Contents and
the Map Display area.
© ECAI, 2002
Common Theme Operations
 Control visibility
 Specify active themes (raised)
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.
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.
 Change display order (by dragging)
Department of Geography
University of Portsmouth
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
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.
Marker Palette
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University of Portsmouth
Fill Palette
Font Palette
Color Palette
Pen Palette
A palette is a
collection of
symbols and
colors – all
the palettes
in ArcView
are
collectively
referred to
as the
Symbol
window.
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
Department of Geography
University of Portsmouth
© 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
Department of Geography
University of Portsmouth
© 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
Department of Geography
University of Portsmouth
© 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
Department of Geography
University of Portsmouth
© ECAI, 2002
Sasanian Publication in TimeMap
 Zoom in to see
more
information.
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University of Portsmouth
© 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.
Department of Geography
University of Portsmouth
© 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.
Department of Geography
University of Portsmouth
© ECAI, 2002
Sasanian Publication in TimeMap
 View border
for different
time ranges
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University of Portsmouth
© ECAI, 2002
Sasanian Publication in TimeMap
 Control which
layers display
based on time.
Department of Geography
University of Portsmouth
© 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
Department of Geography
University of Portsmouth