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2/20/2017
G.P. Singh
Senior Technical Director
(http://gis.up.nic.in)
Overview of GIS
2/20/2017
Topics Covered
Introduction (Why GIS)
GIS Components and Terminology
Case study of Web Enabled GIS Framework „SRISHTI‟
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Introduction (Why GIS?)
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Understanding pictures, maps and graphs are much easier than narrative text and statistical tables
Comparison is easy in Graphs and Maps
Introduction (Why GIS?)
2/20/2017
Data presentation on maps is most effective way to discover, understand and communicate information among the stake holders
(popularity and wide use of google-earth)
Introduction (Why GIS?)
2/20/2017
Geographical Information System (GIS) can help in maps preparation
Power and potential of GIS is limited only by one‟s imagination.
Introduction (Why GIS?)
2/20/2017
GIS Components and Terminology
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GIS Components and Terminology
Specific applications / decision making objectives
?G I S
Spatial data
Computer hardware / software tools
GIS Components
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Georeference some thing means to define its existence in physical space.
Establishing its location in terms of map projections or coordinate systems
WGS 84 is the reference coordinate system used by the Global Positioning System (GPS)
GIS Components and
Terminology (Georeferencing)
2/20/2017
When data from different sources need to be combined and then used in a GIS application, it becomes essential to have a common referencing system.
GIS Components and
Terminology (Georeferencing)
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Point
Line
Polygon
GIS Components and
Terminology (Spatial Survey)
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Line Roads
Canals
Point Building (such as
schools, panchayatghar, recreation center, etc.)
Puliya
Hand pump
Well
Tube well
GIS Components and
Terminology (Features)
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Map Projection
Although for many mapping applications theearth can be assumed to be a perfectsphere, there is a difference between thedistance around the earth between thepoles versus the equator. Thecircumference of the earth is about 1/300thsmaller around the poles. This type of figureis termed an oblate ellipsoid or spheroid,and is the three-dimensional shapeobtained by rotating an ellipse about itsshorter axis.
GIS Components and Terminology
(Map Projection)
2/20/2017
An estimate of the earth‟s surface based onan ellipsoid provides a determination of theelevation of every point on the earth‟ssurface, including sea level, and is oftencalled a datum. Over time, and in differentcountries, many datums have been developedand used. With more accurate means ofmeasurement today (i.e. satellite and GPS),recent datums are referenced from the centerof the earth rather than a theoretical surface.The resulting North American Datum of 1983(NAD83)and the slightly refined WorldGeodetic System (WGS84), from the U.S.Military in 1984, are internationally acceptedas the geodetic reference system (GRS 80).
GIS Components and Terminology
(Map Projection)
2/20/2017
Geographic Coordinates simply refers to thesystem of latitude and longitude. Thiscoordinate system is formed by creating agrid using the equator as 0 degrees andforming parallels of latitude to the north andsouth (90 degrees N is the North Pole, 90degrees S is the South Pole), and meridians oflongitude east and west (which meet at 180degrees, commonly called the InternationalDate Line) of the "Prime Meridian" whichpasses through Greenwich, England.Map projections are used to transfer or“project” geographical coordinates onto a flatsurface.
GIS Components and Terminology
(Map Projection)
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Map projections are used to transfer or“project” geographical coordinates onto a flatsurface.
http://maps.unomaha.edu/Peterson/gis/
GIS Components and Terminology
(Map Projection)
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The Global Positioning System, usually called GPS is a satellite navigation system used for determining one's precise location and providing a highly accurate time reference almost anywhere on Earth.
A GPS receiver decodes time signal transmissions from multiple satellites and calculates its position in the form of
Latitude and Longitude.
Global Positioning System
GIS Components and
Terminology (GPS)
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Over laying Spatial data of different features
GIS Components and
Terminology (Layering)
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Case Study of Web Enabled GIS Framework
„SRISHTI‟ http://gis.up.nic.in
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Tools and Applications
Open SourceMapserverQuantumGISMapGuidepgSQL and postGISGeoServer…..…..
ProprietyESRI ArcGISPitney Bouse Software mapInfoPCI „Geomatica‟ (image processing)…..…..
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Framework Components
1.Mapserver2.Mapscript3.PHP4.pgSQL5.PostGIS6.Google maps API
http://ms4w.comhttp://mapserver.orghttp://postgresql.orghttp://postgis.nethttp://developers.google.com/maps
2/20/2017
Thanks
