introduction to geographic information...
TRANSCRIPT
Introduction to GeographicInformation Systems
Environment and Land Planning Applications
Prof. Maria Antonia BrovelliPolitecnico di Milano
Polo Regionale di Como
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An information system is an organized set of
procedureshuman resourcesmaterial resources
used to
gatherstoreprocesscommunicate
information needed by an organization to manage itsoperational and government activities.
Definition of Information System
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We define GIS (Geographic Information System) as a structureconstituted by a powerful set of instruments and technologiescommitted to acquire, store, manage, transform, analyze and visualizegeoreferenced spatial data.
Georeferenced information: every document or event referred to a particular portion of Earth’s surface is an example of georeferencedinformation
Geospatial information: every document or event that is alsorepresented 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 assynonyms.
Geographic Information System
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Spatial or geographic data represent REAL WORLD PHENOMENA and they are characterized by:
their POSITION in space with respect to a reference and coordinate systemNON-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
Geographic Information System
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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 construction of large-scale geographic information systems. International J. of Geographical Information Systems, 1: 13-31.
“any manual or computer based set of procedures used to store andmanipulate geographically referenced data”Aronoff S., 1989. Geographic Information Systems: A Management Perspective. WDL Publ., Ottawa, Canada.
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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
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•Data (geographic information models and structures)•Organizational structures and work methods•Software components•Hardware components
computerdigitizerplotterprinterCD/DVD reader/writer
Components of a Geographic Information System
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Functionalitiesof a GIS engine
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REALITYa) Conceptual models
of the world
COMPLETELY DEFINED and DEFINABLE
OBJECTS/ENTITIES
NOT COMPLETELY DEFINED and DEFINABLE SPATIAL
ENTITIES
CONTINUOUS and SLOWVARIATIONS
OBJECTS ARE FORMED OF SIMPLER ENTITIES (ATOMIC
ENTITIES), THEIR ATTRIBUTES AND THEIR
MUTUAL RELATIONS
THE WORLD CONSISTS OF SETS OF DISCRETE OBJECTS,
WITH ATTRIBUTES AND MUTUAL RELATIONS
THE WORLD CONSISTS OF CONTINUOUS AND SLOWLY
CHANGING FIELDS
SAMPLING AND/OR INTERPOLATION(SCANNED IMAGES,
INTERPOLATED SURFACES)
CONTINUOUS MATHEMATICAL
FUNCTIONS
DISCRETIZED SURFACES CONTINUOUS NON-DIFFERENTIABLE MATHEMATICAL
EQUATIONS(FRACTALS, STOCHASTIC
SURFACES)
OBJECTSFILTERING
b) Data models
c) Representation
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GIS environment/landscapeplanning applications
• Environment/landscape condition: analysis and
control
Human activities planning
Environment/landscape-oriented actions
• Research in environment/landscape planning fields
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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)
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Environment/landscape planning GIS purposes - 2
Examples:
automate the elaboration of an Environmental Assessment
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: meteorologicalanalysis (Steve Hall, Markus Neteler)
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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?
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Outline of an environmental GIS
• Data modeling in environmental GIS
• Basic functionalities
• Specific functionalities
BASIC FUNCTIONALITIES
SPECIFICFUNCTIONALITIES
ENVIRONMENTAL DATA (GEOREFERENCED OR NOT)
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Environmental GIS data• Vector and raster maps
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Example: download fromhttp://www.cartografia.regione.lombardia.it/geoportale
DEMO:try byyourself!
your request succeeded!check your email box
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InstallQuantum GIS on yourcomputer;in the exampleQuantum GIS 1.6
Open yourvectordata
Where find I Quantum GIS? http://www.qgis.org/wiki/Download
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M.A.Brovelli - Introduction to Geographic Information Systems
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Environmental GIS data
• Field observations
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Environmental GIS data
• Orthoimages and remotelysensed images
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Environmental GIS data
• Digital Surface Models(DSM) and Digital TerrainModels (DTM)
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Environmental GIS data
• Primary thematic maps
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Environmental GIS data
• Derived thematic maps