Transcript Modeling in GIS - CE Meeting

Spatial Data
Chapter 2
What is a model?
• Simplified view of the real world
GIS Data Model
The GIS Data Model: Purpose
• allows the geographic features in real
world locations to be digitally represented
and stored in a database so that they can be
abstractly presented in map (analog) form,
and can also be worked with and
manipulated to address some problem
Information and data
• Data
– Collection of facts
• Information
– Data with meaning and context
Three modes of data
• Temporal
• Thematic
• Spatial
Lat 43°
Long 81°
What makes a good map?
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Establish purpose
Define the scale
Select the features
How represented
Generalize
Map projection
Spatial referencing
annotate
Establish Purpose
• What do we
want to portray?
• Happy Valley
– Help orient
people
– Decide how to
spend time
Scale
• Ratio
– 1:5000
• Verbal
– 1 cm represents 50 m
• Graphic
Note that:
Large Scale maps
-Hamilton
-1:10,000
Small Scale Maps
-Canada
-1:1,00,000
Spatial Entities
• Points
– elevations
• Lines
– elevations
• Areas
– Island and adjacent polygons
• Dependent on scale
– Small scale city a point
– Large scale city a area
Generalization
• All spatial data are a generalization of real
world
Cartographic Generalization
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Selection
Simplification
Displacement
Smoothing and enhancement
Topology
• Objects do not change
when
– Stretched or bend
– Independent of
coordinate system
• Three elements
– Adjacency
– Containment
– Connectivity
Attribute data types
Categorical (name):
Numerical
Known difference between values
– nominal
• no inherent ordering
• land use types, county names
– ordinal
• inherent order
• road class; stream class
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often coded to numbers eg SSN but
can’t do arithmetic
– interval
• No natural zero
• can’t say ‘twice as much’
• temperature (Celsius or
Fahrenheit)
– ratio
• natural zero
• ratios make sense (e.g. twice as
much)
• income, age, rainfall
• may be expressed as integer
[whole number] or floating point
[decimal fraction]
Attribute data tables can contain locational information, such as addresses
or a list of X,Y coordinates. ArcView refers to these as event tables. However,
these must be converted to true spatial data (shape file), for example by
geocoding, before they can be displayed as a map.
Data Acquisition
• Five Essential Functions of a GIS
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Data Acquisition
Preprocessing
Data Management
Manipulation and Analysis
Project Generation
• Data Acquisition and Preprocessing
– Biggest part-80% of time and cost
– Two types data
• Spatial
• Non-spatial (attributes)
Collection Methods
• Field data collection
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Land surveys
Soil sampling
Tree inventory
Tracking wild animals
Census Data
Remote Sensing
Surveying or GPS
LIDAR
Donated, traded or bought
Paper or digital
Methods of Collecting Data
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Existing data,
downloads from field
Keyboard
COGO
Methods of Gathering data
• Digitizing and
scanning
Scanner
Raster to Vector
Digitizing
Software for GIS: The Main Players
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ESRI, Inc., Redlands, CA
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clear market leader with about a third of the market
originated commercial GIS with their ArcInfo product in 1981
privately owned by Jack Dangermond, a legend in the field
Strong in gov., education, utilities and business logistics
The main two
“pure GIS”
companies.
MapInfo, Troy N.Y.
– Aggressive newcomer in early 1990s, but now well-established.
– Strong presence in business, especially site selection & marketing, and telecom
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Intergraph (Huntsville, AL)
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origins in proprietary CAD hardware/software
Older UNIX-based MGE (Modular GIS Environment) evolved from CAD
“new generation” GeoMedia product based on NT is now their main focus
strong in design, public works, and FM (facilities management)
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Bentley Systems (Exton, PA)
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– MicroStation GeoGraphics, originally developed with Intergraph, is now their exclusive and
main product..
– Strong in engineering; advertises itself as “geoengineering”
Autodesk (San Rafael, CA)
– Began as PC-based CAD, but now the dominant CAD supplier
– First GIS product AutoCAD Map introduced in 1996
– Primarily small business/small city customer base
Software for GIS: other players
Vector GIS
• Smallworld Systems
(Englewood, CO)
– first to use OO (early ‘90s),
but failed to compete as
established vendors did same
– Purchased by GE in 2000
– emphasis on FM & utilities
• Manifold
(CDA International Corp):
– low cost, but low market
share
• Maptitude
(Caliper Corp, Newton, MA):
Raster GIS
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ERDAS/Imagine
– long established leader
– acquired by Leica Geosystems in 2001
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ER MAPPER
– aggressive newcomer originating in Australia
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Envi,
– relative newcomer, radar specialization
– acquired by Kodak in 2000
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PCI--Geomatica
– long-term Canadian player
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CARIS
– newer Canadian entry
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GRASS (Rutgers Univ.)
– Classic old-timer originally developed by US
Army Construction Engineering Research
Lab(CERL) in Champaign, IL;
– army ended dev. & support in 1996 but
assumed by Baylor University.
– another low cost one
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IDRSI (Clark Univ)
– pioneering, university-developed package
ESRI Product Line-up: ArcGIS client products (Fall
ArcReader (“adobe acrobat” for maps) & ArcExplorer (spatial data viewer)
2004)
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Free viewers for geographic data.
ArcGIS 9.x Desktop: two primary modules (MS NT/2000/XP only)
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ArcMap: for data display, map production, spatial analysis, data editing
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ArcCatalog: for data management and preview
ArcToolbox, for specialized data conversions and analyses, available as a window in both
Available capabilities within these modules are “tiered”
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ArcView: viewing, map production, spatial analysis, basic editing
ArcEditor: ArcView, plus specialized editing
ArcInfo: ArcView & ArcEditor plus special analyses and conversions
Extensions: for special apps.: Spatial Analyst, 3D Analyst, Geostatistics, Business Analyst, etc.
ArcObjects: build specialized capabilities within ArcMap or ArcCatalog using VB for Applications
ArcGIS Workstation (for UNIX and MS NT/2000/XP)
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the old command line ArcInfo 7.1
ArcGIS Engine (MS NT/2000/XP)
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Set of embeddable GIS components (ArcObjects software objects) for use in building custom
applications
Runs under Windows, Unix and Linux, with support for Java, C++, COM and .NET
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Replaces MapObjects which were based upon a previous generation of GIS objects
Notes:
ArcGIS 8 released 2000 to integrate two previous standalone products: ArcView and ArcInfo
ArcGIS 9 released 2004 providing the full capability that should have been in ArcGIS 8!!!
--full support for all data types (coverages, shapefiles, geodatabases)
--full support for all previous geoprocessing analyses
--Modelbuilder for scripting and repetitive processing
--ArcEngine for building custom applications
ArcView 3.3 (the predecessor to ArcGIS 8.x) the only GUI option for UNIX.
ESRI Product Line-up: ArcGIS server products (Fall
2004)
SDE (Spatial Database Engine)
– middleware to support spatial data storage in standard DBMS
– Supports all major industry databases:
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Oracle, SQL-Server, IBM DB2, Ingres
ArcGIS Server
– Permits the creation of server-based GIS services using any ArcGIS
capability
– Provides GIS capabilities to a user without a desktop GIS system:
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inward focus—user goes to server
ArcIMS
– Software to develop Internet server-based mapping and basic analysis
– Provides maps to the user without a desktop GIS system :
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outward focus—gives user a map
ArcGIS Services
– Server based applications built and operated by ESRI or its partners and
made available on the Internet for subscription
– Normally charged on a “per transaction” basis, but can be flat fee
– presumably built using ArcGIS Server
ArcGIS System
c:\ ArcGIS Workstation
Clients
ArcInfo
ArcEditor
ArcView
ArcMap
ArcCatalog
ArcToolbox
ArcMap
ArcCatalog
ArcToolbox
ArcMap
ArcCatalog
ArcToolbox
ArcEngine/
ArcObjects
Application
Development &
Customization
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Consistent interface
Increasing capability
ArcExplorer
ArcServer Services
ArcIMS Services
ArcSDE Services
Internet
ArcPad
Files
Handheld/Wireless
Browser
(Personal Geodatabase,
Shapefiles, Coverages,
Grids, tins, etc)
Databases
Multi-user Geodatabases
(in Oracle, SQL Server,
IBM DBII, etc)
Source: ESRI with mods.