Introduction to Geographic Information Systems

Introduction to Geographic Information Systems

Environment and Land Planning Applications

Prof. Maria Antonia Brovelli Politecnico di Milano Polo Regionale di Como

Definition of Information System An information system is an organized set of procedures human resources material resources used to gather store process communicate information needed by an organization to manage its operational and government activities. M.A.Brovelli - Introduction to Geographic Information Systems

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Geographic Information System We define GIS (Geographic Information System) as a structure constituted by a powerful set of instruments and technologies committed to acquire, store, manage, transform, analyze and visualize georeferenced spatial data. Georeferenced information: every document or event referred to a particular portion of Earth’s surface is an example of georeferenced information Geospatial information: every document or event that is also represented from a cartographic point of view or by maps or aerial/satellite images is an example of geospatial information Often the two terms (georeferenced and geospatial) are used as synonyms. M.A.Brovelli - Introduction to Geographic Information Systems

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Geographic Information System Spatial or geographic data represent REAL WORLD PHENOMENA and they are characterized by: their POSITION in space with respect to a reference and coordinate system NON-SPATIAL ATTRIBUTES (color, temperature, etc…) mutual SPATIAL RELATIONS (topological, directional, distance relations) The definition of a GIS contextually requires the definition of its objectives and methods

 GIS OBJECTIVES means the set of results pursued at the moment of the definition and creation of the GIS itself

 GIS METHODS means the set of operators, coded in an abstract

form, which allows to accomplish such objectives M.A.Brovelli - Introduction to Geographic Information Systems

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Definitions ... a) GIS definitions based on the concept of Database “A database system in which most of the data are spatially indexed, and

upon which a set of procedures operated in order to answer queries about spatial entities in the database” Smith T.R., S. Menon, J.L. Starr, and J.E. Estes, 1987.Requirements and principles for the implementation and large-scale geographic information systems. International J. of Geographical Information Systems, 1: 13-31.

construction of

“any manual or computer based set of procedures used to store and manipulate geographically referenced data”

Aronoff S., 1989. Geographic Information Systems: A Management Perspective. WDL Publ., Ottawa, Canada.

M.A.Brovelli - Introduction to Geographic Information Systems

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Definitions ... b) GIS defined as a structure constituted by a set of instruments and technologies “a powerful set of tools for collecting, storing, retrieving at will,

transforming and displaying spatial data from the real world”

Burrough P., McDonnel A. (1998) – Principles of Geographical Information Systems – Oxford University Press, Oxford

“A system for capturing, storing, checking, manipulating, analysing and displaying data which are spatially referenced to the Earth ”

Department of Environment (DoE), 1987. Handling Geographic Information. HMSO, London, 1988

c) GIS definitions based on organizational aspects “a decision support system involving the integration of spatially referenced data in

a problem solving environment”

Cowen D.J., 1988. GIS versus CAD versus DBMS: what are the differences? Photogrammetric Engineering and Remote Sensing, 54: 1551-1554 M.A.Brovelli - Introduction to Geographic Information Systems

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Components of a Geographic Information System •Data (geographic information models and structures) •Organizational structures and work methods •Software components •Hardware components computer digitizer plotter printer CD/DVD reader/writer


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Functionalities of a GIS engine8

a) Conceptual models of the world

COMPLETELY DEFINED and DEFINABLE OBJECTS/ENTITIES

REALITY

NOT COMPLETELY DEFINED and DEFINABLE SPATIAL ENTITIES

CONTINUOUS and SLOW VARIATIONS

SAMPLING AND/OR INTERPOLATION

(SCANNED IMAGES, INTERPOLATED SURFACES)

b) Data models THE WORLD CONSISTS OF SETS OF DISCRETE OBJECTS, WITH ATTRIBUTES AND MUTUAL RELATIONS

OBJECTS FILTERING

THE WORLD CONSISTS OF CONTINUOUS AND SLOWLY CHANGING FIELDS

c) Representation OBJECTS ARE FORMED OF SIMPLER ENTITIES (ATOMIC ENTITIES), THEIR ATTRIBUTES AND THEIR MUTUAL RELATIONS

DISCRETIZED SURFACES

CONTINUOUS MATHEMATICAL FUNCTIONS


CONTINUOUS NONDIFFERENTIABLE MATHEMATICAL EQUATIONS (FRACTALS, STOCHASTIC 9 SURFACES)

GIS environment/landscape planning applications • Environment/landscape condition: analysis and control Human activities planning Environment/landscape-oriented actions

• Research in environment/landscape planning fields M.A.Brovelli - Introduction to Geographic Information Systems

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Environment/landscape planning GIS purposes - 1 • Production of geographic archives, thematic maps and inventories (both local or accessible through the Internet) M.A.Brovelli - Introduction to Geographic Information Systems

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Environment/landscape planning GIS purposes - 2 Examples:  automate the elaboration Environmental Assessment

of

an

 automate the formation of instruments to support eco-planning and land planning government;  priorities selection and environmental policies adjustment to create environmental Action Plans.


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Environment/landscape planning GIS purposes - 3  Scientific research in environment / landscape planning fields:

3D models of the GRASS GIS: meteorological analysis (Steve Hall, Markus Neteler) M.A.Brovelli - Introduction to Geographic Information Systems

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Scales for GIS applications • Microlocal (e.g.: quarry control) • Local (e.g.: drainage interventions) • Regional (es: avalanche control) • National (es: disaster forecasting) • Continental/Global  obviously the GIS will have different resolutions / detail levels

What is the scale of a GIS? M.A.Brovelli - Introduction to Geographic Information Systems

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Outline of an environmental GIS ENVIRONMENTAL DATA (GEOREFERENCED OR NOT)

• Data modeling in environmental GIS

• Basic functionalities

• Specific functionalities

BASIC FUNCTIONALITIES SPECIFIC FUNCTIONALITIES


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Environmental GIS data • Vector and raster maps


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Example: download from http://www.cartografia.regione.lombardia.it/geoportale

DEMO: try by yourself! M.A.Brovelli - Introduction to Geographic Information Systems

your request succeeded! check your 17 email box

Install Quantum GIS on your computer; in the example Quantum GIS 1.6

Where find I Quantum GIS? http://www.qgis.org/wiki/Download

Open your vector data M.A.Brovelli - Introduction to Geographic Information Systems

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set transparency


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Environmental GIS data • Field observations


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Environmental GIS data

• Orthoimages and remotely sensed images


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• Digital Surface Models (DSM) and Digital Terrain Models (DTM)


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• Primary thematic maps


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• Derived thematic maps


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