Introduction to GIS...Introduction to GIS Dr. M.S. Ganesh Prasad Department of Civil Engineering The...
Transcript of Introduction to GIS...Introduction to GIS Dr. M.S. Ganesh Prasad Department of Civil Engineering The...
Introduction to GIS
Dr. M.S. Ganesh Prasad
Department of Civil Engineering
The National Institute of Engineering, MYSORE
9449153758
Geographic Information System (GIS)
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Information System
Geographic Position
So, what is GIS?
A method to Analyze, Manipulate, Visualize and Display Data.
Geographical Data
Where is it? (Spatial)
Geographical coordinates
What is it? (Non-spatial)
Attributes
What is their relation with each other?
Topology
What makes data spatial?
Placename Grid co-ordinate
Postcode
Distance & bearing Description
Latitude / Longitude
Representing Spatial Data
Points - simplest element
Lines (arcs) - set of connected points
Polygons - set of connected lines
We typically represent objects in space as three
distinct spatial elements:
We use these three spatial elements to represent real world features and
attach locational information to them.
Point Features
Spatially distributed entities, activities or events
• Points have a single geographic coordinate such as:
– Tree
– Traffic accident
– Lamp post
Line Features
Spatially distributed entities, activities or events
• Lines (Arcs) are a series of geographic coordinates joined to form a line such as:
– Road
– Stream
– Railway
Area Features Spatially distributed entities, activities or events
• Areas (Polygons) are a series of geographic coordinates joined together to form a boundary such as:
– Lake
– Soil types
Attributes
Description or characteristic of a feature
• Possible attributes for the feature Tree
– Height
– Diameter
– Species
– Condition
– Age
Attribute Values The value given to an attribute
• Possible values for the attributes of a Tree feature
– Height = 15m
– Diameter = 0.75m
– Species = Oak
– Condition = Good
– Age = 8 years
Data Acquisition
• Primary data – Field Surveying: Total Stations, GPS – Photogrammetry: Analogue, Digital – Remote Sensing: Active, Passive
• Secondary data – Raster data capture using scanners – Vector data capture using digitizer
• Data from external sources (CAD files, different data formats etc.)
• Capturing Attribute data (Tables, statistical records, census etc.)
Field Surveying
GPS Satellites
Measurement from a distance
Remote Sensing
Data from Maps: Scanners
Data from Maps: Digitizer
Data Storage and Management
• Data Base Management
– Systems – Entry, Editing, Report, Masking
– Retrieval – Query, SQL
• Data Compaction
– Relational Database models
– Object-Oriented Database models
Data Analysis Functions
• Transformation Functions (Map Projection, Vector to Raster & vice versa)
• Classification & measurement functions
• Overlay functions
• Neighborhood functions
• Topographic and interpolation functions
• Proximity functions(Buffering)
• Network functions
• Inter-visibility functions
• And many more ……
Data - Spatial & Tabular
Spatial Data: Any entity that has location and can be shown on a map. E.g., Boundaries of States of India.
Tabular Data: Attributes of the spatial entity. E.g., State wise Per Capita Income.
Some GIS Software
• IDRISI
• ILWIS
• ARC-INFO (ARC-GIS)
• ARC VIEW
• MGE
• GRASS
• GISPAD
To summarise GIS comprises of:
• Data input
• Storage
• Management
• Analysis
• Output
GIS has many applications
• Geosciences (especially geography, ecology, geology, geophysics, geodesy)
• Surveying and cadastral mapping
• Digital topographic and thematic mapping
• City and landscape planning
• Military applications
• Pipeline and route planning, public utilities, facilities management
• Forestry
• Health and Insurance
• Marketing, retailing and many more………
Some current applications of GIS
Agriculture
Monitoring and management from farm to National levels
Archaeology
Site description and scenario evaluation.
Environment
Monitoring, modeling, and management for land degradation;Land evaluation and rural planning; landslides; desertification; Water quality and quantity; plagues; air quantity; weather and climate modeling and prediction.
Epidemiological and Health
Location of disease in relation to environmental factors.
Forestry
Management, planning and optimizing extraction and replanting.
Emergency services Optimizing fire, police and ambulance routing; improved understanding of crime and its location.
Navigation
Air, sea and land.
Marketing
Site location and target groups; optimizing goods delivery.
Real Estate
Legal aspects of the cadastre, property values in relation to location, insurance.
Regional / local Planning
Development of plans, costing, maintenance, management.
Some current applications of GIS
Road and rail
Planning and management.
Site evaluation and Costing
Cut and fill, computing volumes of materials.
Social studies
Analysis of demographic movements and developments.
Tourism
Location and management of facilities and attractions.
Utilities
Location, management, and planning of water, drains, gas, Electricity, telephone, cable services.
Some current applications of GIS
Attribute data of houses:
house number
area of the house
area of the site
site number
type of construction
address
house tax (paid or not)
tax last paid
water tax
number of persons ( male and female )
family income etc…
What difference can GIS make?
Muncipal Uses of GIS
Town planning (and development of civic amenities
like schools, hospitals, fire stations, shopping)
Utility management.
Socio-economic planning (projecting future
population)
Property taxation.
Transportation system and traffic management.
Planning, development and managing the utilities
like water supplies, sewerage system, water supply,
telephone system and power.
Solid waste management etc..