GIS Geographical Information System Dr Kodge B G
GIS (Geographical Information System) Dr. Kodge B. G. SVITM, Udgir, Dist. Latur (MS) kodgebg@svspm. edu. in
What is GIS? • A technology – hardware & software tools • An information handling strategy • The objective: to improve overall decision making
GIS: a formal definition “A system for capturing, storing, checking, integrating, manipulating, analysing and displaying data which are spatially referenced to the Earth. This is normally considered to involve a spatially referenced computer database and appropriate applications software”.
GIS: historical background This technology has developed from: – Digital cartography and CAD – Data Base Management Systems ID 1 2 3 1 2 X, Y ID 1 2 3 ATTRIB 3 CAD System Data Base Management System
Digital Mapping Computer Aided Design Photogrammetry GIS Databases Surveying Remote Sensing Cross-disciplinary nature of GIS
GIS components Spatial data GIS Computer hardware / software tools Specific applications / decision making objectives
What makes data spatial? Grid co-ordinate Placename Latitude / Longitude Postcode Description Distance & bearing
Characteristics of spatial data Geometry • The shape of a building or county • The course of a river, the route of a road • The shape of the landscape, relief
Characteristics of spatial data • Topology · Connected to · Within · Adjacent to · North of. . .
Spatial Data: examples • Socio-economic data – Regional health data – Consumer / lifestyle profiles – Geodemographics • Environmental data – Topographic data – Thematic data, soils, geology
Spatial data storage • Vector model • Raster model as geometric objects: points, lines, polygons as image files composed of grid-cells (pixels)
• Date type – Integer – Real – Byte • File type – ASCII – Binary – Packed Binary or depends of the DBMS package…
Vector data model • advantage of the vector data format: allows precise representation of points, boundaries, and linear features. – useful for analysis tasks that require accurate positioning, – for defining spatial relationship (ie the connectivity and adjacency) between coverage features (topology), important for such purposes as network analysis (for example to find an optimal path between two nodes in a complex transport network) • main disadvantage of vector data is that the boundaries of the resulting map polygons are discrete (enclosed by well-defined boundary lines), whereas in reality the map polygons may represent continuous gradation or gradual change, as in soil maps.
Raster data model • good for representing indistinct boundaries – thematic information on soil types, soil moisture, vegetation, ground temperatures • as reconnaissance satellites and aerial surveys use raster-based scanners, the information (ie scanned images) can be directly incorporated into GIS • the higher the grid resolution, the larger the data file is going to be
Modelling the real world y 1 1 20 50 1 2 24 45 1 3 52 55 x 2 1 0 45 46 40. . . 000000020 000001000 02001000020000 2 2 2 0 1. . .
Vector data Land use parcels
Raster data
Manipulation and analysis • What would happen if. . . A chemical leaked into a river? • Where does. . . The Green Belt exist in relation to the City? • Has. . . Population changed over the last ten years? • Is there a spatial pattern related to. . . Car ownership in our area?
Databases & GIS Spatial data • At a simple level a GIS may just form the graphical interface to a database • The majority of GIS applications follow this example Map. Info Linked database table SQL Query Manager
Geo-relational Data Models • Linked tables based on the relational model, but storing geographical information such as: – Geometry – Topology – Attributes
GIS Data Quality • The data quality refers to ‘fitness for use’ of data for intended applications. • Scope of geo-data quality (reliable, projected, relevant and current/updated). • Accuracy (roundup, inadequate survey ) • Precision (exact single/double float points) • Errors • Uncertainty (lack of data confidence)
Sources of Errors in GIS • Sources Map Projection Map Scale Field survey measurements Image analysis Sampling design Digitizing Raster to vector Overlay analysis Attribute data input Inherent Y Y Y Y Y Operational N N Y Y N N Y
GIS & Analysis In the context of GIS, analysis is. . . “Deriving new information from existing data” It is also the manipulation of data to solve a problem e. g. identify all areas within 500 m of a lake Increasing use is made of the analytical capabilities of GIS, BUT many GIS projects only use the software to store and manage geographical data Yet analysis often relies on many simple basic GIS techniques
Simple Query • The identification of objects and their attributes either by location or attribute query.
Buffering • Creation of an area of interest around an object – proximity analysis and environmental impact assessment.
Overlays • Layer: A thematic plane of GIS features containing geographically and logically related data • Overlaying involves superimposing two or more map layers to produce a new map layer. • Example: a new genetically engineered variety of wheat grows well in dry environments, with long growing seasons and alkaline soils. Given the availability of data on the length of the growing season, moisture regime and soil alkalinity, where is the best place to plant the wheat? – overlaying (superimposing) several maps showing (separately) water-budget, growing season length, soil p. H, sodium content, and so on. The GIS analysis can establish the locations where all the favorable soil conditions coincide, as the places where the wheat will grow best.
Country boundary
Plus district boundary
Plus major rivers
Plus major roads
Plus railway lines
Plus domestic air routes
Plus district towns
More functions? • • Unioning Distance measuring 3 D modeling Vertical and horizontal scalability Web based operation Data center based operation More ……
The benefits of GIS include: • Better information management • Higher quality analysis • Ability to carry out “what if? ” scenarios • Improve project efficiency
GIS Applications • • • Facilities management Marketing and retailing Environmental Transport/vehicle routing Health Insurance and many more. . .
Finding the best route to evacuate people during cyclone – A GIS application
Important features of cyclone in Bangladesh • In last 30 years, nearly 9, 000 people died due to disastrous cyclones in Bangladesh • Six out of nine depressions formed in the Bay of Bengal normally cross the coastal belt of Bangladesh almost every year • Thousands of people lose lives due to cyclones • Cyclone preparedness can reduce the loss of life and property
LULC of India
LULC of Latur district 2004 -05
LULC of Latur district 2005 -06
LULC of Latur district 2006 -07
LULC of Latur district 2007 -08
LULC of Latur district 2008 -09
LULC of Latur district 2009 -10
Water scarcity regions
Education zone (Udgir)
Village performance map
Digital Terrain Model • DEM, DSM and DTM. • A digital terrain model is a topographic model of the bare earth – terrain relief - that can be manipulated by computer programs. The data files contain the spatial elevation data of the terrain in a digital format which usually presented as a rectangular grid.
DTM of Latur district
Elevation Map
3 D Surface Modeling
3 D Surface Modeling
Route elevation (Latur-Udgir)
TIN
DTM Applications • • Surveying & Mapping Hydrological & Geomorphological Geoscientific Engineering Natural Resource Management Military National developments
GIS Implementation & Project Management • • GIS Project Planning GIS software evaluation and selection Hardware consideration and acquisition GIS Database design methodologies Software Engineering in GIS Software design methodologies System Analysis & User Requirements
GIS Issues and Prospects • GIS Implementation (data, ownership, misusing, privacy, updating, documentation) • Technical issues (Evaluation, speed, memory and Management) • Integration with other applications. • Issues pertaining to people.
The Trend of GIS Development • • • Enterprise computing and GIS Spatial data warehouses Interoperability and Open GIS National spatial data Infrastructure Internet and its impact on GIS
Frontiers of GIS Research • • Spatial data acquisition & Integration Distributed computing Extensions to Geographic representations Scale Spatial analysis in GIS environment Future of spatial information GIS and Society Education and training.
Where to start search • • • GIS Information jump Stations www. gis. com (ESRI portal) Geo. Community (www. geocomm. com) www. gislinx. com http: //map. lib. umn. edu (Minnesota Univ. ) http: //www. calmit. unl. edu (Nebraska linkon) http: //rst. gsfc. nasa. gov/
Pointers to Info. Resources • • NASA EOS (www. eos. nasa. gov) USGS-NIMA (egsc. usgs. gov/nimamaps) NOAA (www. noaa. gov) USGS-SRTM (www. seamless. usgs. gov) OGISC (www. opengeospatial. org) NRSC-Bhuvan (www. bhuvan. nrsc. gov. in) SOI (www. surveyofindia. gov. in) NATMO (www. natmo. gov. in)
Pointers to Data Resources • • ESRI data online (www. esri. com/data) Alexandria project (www. alexandria. ucsb. edu) CIESIN (www. ciesin. org) ARKANSAS CAST (www. cast. uark. edu) GIS data depot (www. data. geocomm. com) DIVA-GIS (www. diva-gis. org/data) Microsoft Terra server (www. terraserver. com) SRTM DEM (http: //srtm. csi. cgiar. org/)
Pointers to Product Info. • • Computer manufacturer’s sites ERDAS Inc. (www. erdas. com) ESRI (www. esri. com) Intergraph (www. intergraph. com) PCI Geomatics (www. pcigeomatics. com) Map. Info (pbinsight. com/welcome/mapinfo) Oracle Corp. (www. oracle. com) Geoeye (www. geoeye. com)
Internet based GIS applications • • Google earth (www. earth. google. com) NASA world wind-worldwind. arc. nasa. gov ARG GIS earth explorer (maps. esri. com) NASA EOS (svs. gsfc. nasa. gov) Indian ATLAS (atlas. gisserver. nic. in) DST-NRDMS-NSDI (http: //nsdiindia. gov. in) VISA card ATM Locator-visa. via. infonow. net
GIS & RS Journals • • American Cartographer Cartography and GIS IEEE T on Computers & Geosciences Geometica Int. Journal of Remote Sensing Transactions in GIS Int. journal of GIS Journal of Remote Sensing of Envi.
Thanks to all…
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