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Geographic Information Systems. Ted Sickley 18 February 2003 Principles of Landscape Ecology. Definition (academic). The organized activity by which people measure aspects of geographic phenomena and processes;

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Geographic InformationSystems

Ted Sickley

18 February 2003

Principles of Landscape Ecology


Definition(academic)

  • The organized activity by which people

    • measureaspects of geographic phenomena and processes;

    • representthese measurements, usually in the form of a computer database, to emphasize spatial themes, entities, and relationships;

    • operate upon these representations to produce more measurements and to discover new relationships by integrating disparate sources; and

    • transformthese representations to conform to other frameworks of entities and relationships.

  • These activities reflect the larger context (institutions and cultures) in which these people carry out their work. In turn, the GIS may influence these structures. GIS course notes, University of Washington


Definition(on-line computer dictionary)

(GIS).A computer system that has maps and geographic information, and sometimes analyses of geographic data. Geographic information systems have many uses including government, tourist information, education, environmental information, engineering, marketing.

From “High-Tech Dictionary” at www.computeruser.com


Definition(GIS software vendor)

A geographic information system (GIS) is a computer-based tool for mapping and analyzing things that exist and events that happen on earth.

ESRI

GIS stands for Geographic Information Systems. A Geographic Information System is a combination of elements designed to store, retrieve, manipulate, and display geographic data - information about places. It is a package consisting of four basic parts: hardware, software, data and a thinking operator.

ESRI Canada


SPATIAL

DATA IN

ANALYZE/

PROCESS

DATA OR

GRAPHICS

OUT

Scanner

Network

Screen

Digitizing

Table

Computer

CD

CD

Spatial

Database

Printer

FTP


Vegetation

Distribution

Climate

y

x1

x2

x3

Probability of

Model

Soils

= f(c, s, t)

Topography

SPATIAL

DATA IN

ANALYZE/

PROCESS

DATA OR

GRAPHICS

OUT


In practice

HardwareSoftwareDatathe Thinking Operator


Hardware Computer Global positioning system (GPS) Input scanner

digitizing table PDA, data logger

Output printer or plotter

export data or digital image

Network connection

SoftwareDatathe Thinking Operator


Hardware

Software GIS software image processing analysis packages

spreadsheets

relational databases

statistical (SAS, S-Plus, Oracle have GIS and spatial statistics modules)

Datathe Thinking Operator


HardwareSoftware

Data spatially referenced information land cover, elevation, population density, utility

networks, rare species locations

the Thinking Operator

Images from www.esri.com


On a more conceptual level

Data model

how the world is represented digitally

Cartographic and analytical tools

display spatial data

manipulate, analyze data


Data model – how the world is represented digitally

Geographic features

streams

census blocks

bird nesting sites, etc.

Database containing attribute information

width, order, invertibrate fauna, flow

age, income, number of bathrooms

species, success, habitat

Cartographic and analytical tools


Spatial Data Components

Spatial Data

Geographic

Component

Attribute

Component

Qualitative

Quantitative

Vector: point, line, polygon topology

Raster: pixel

Ordinal

Interval

Ratio

Categorical


  • Vector vs. Raster

    Advantages of vector:

    • Good representation of entity data models

    • Space efficient storage of data

    • Topology can be described explicitly and be easily manipulated

    • Efficient query operation

      Advantages of raster:

    • Simple data structure

    • Efficient representation of highly variable data

    • Mathematical modeling easier because all entities have simple, regular shape


Data sources

Project generated

Historic maps/documents

Government agencies

Dane County

MN Data Deli

USGS

Private vendors

Internet

Geography Network

Spatial data clearinghouses


Data model – how the world is represented digitally

Cartographic and analytical tools

Mapping

Visualization

Spatial overlay

Spatial modeling

Pattern analysis

Interpolation

Statistical analysis

Network analysis

Data management

Images from www.esri.com



y = 0

y = 30

y = 50

http://www.alpine-lis.com/visualization.htm


Issues, concerns

Generalization, simplification

Scale

Accuracy, precision

Error

Metadata


Users

Landscape ecology research labs

Land management agencies USFS, NPS, DNR, TNC forest products, petroleum companies

Governmental agencies: all levels land records, facilities/utilities management, environmental regulation

Business demographic analysis marketing site selection

the press





Hall, M.H.P. and D.B. Fagre. 2003. Modeling climate-induced glacier change in Glacier National Park, 1850-2100. BioScience 53, 131-140

1850-1993, 73% reduction in glacial cover in Glacier NP

Important as evidence of changing climate

Digitized terminal moraine positions 1850-1979

Related glacial extents to physiographic factors and climatic drivers


Hall, M.H.P. and D.B. Fagre. 2003. Modeling climate-induced glacier change in Glacier National Park, 1850-2100. BioScience 53, 131-140

Assigned a probability of melt factor to each cell in their study area

Modeled glacial distribution into the future under 2 warming scenarios

Also ran companion vegetation distribution model to assess reaction of vegetation to changes in soil moisture and increasing temperature


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