Introduction to GIS Dr. M.S. Ganesh Prasad Department of Civil Engineering The National Institute of Engineering, MYSORE ganeshprasad.nie@gmail.com 9449153758
Geographic Information System (GIS) 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? Grid co-ordinate Placename Latitude / Longitude Postcode Description Distance & bearing
Representing Spatial Data We typically represent objects in space as three distinct spatial elements: Points - simplest element Lines (arcs) - set of connected points Polygons - set of connected lines 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
Photogrammetry
Remote Sensing Measurement from a distance
Data from Maps: Scanners
Data from Maps: Digitizer
Data Storage and Management Data Base Management Systems Retrieval Entry, Editing, Report, Masking 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 Archaeology Monitoring and management from farm to National levels Site description and scenario evaluation. Environment Epidemiological and Health 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. Location of disease in relation to environmental factors. Forestry Management, planning and optimizing extraction and replanting.
Some current applications of GIS 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.
What difference can GIS make? 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
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..