BASICS OF GEOGRAPHICAL INFORMATION SYSTEM (GIS)

Ø   Geographical Information system is a system of all hardware, different types of software and process to facilitate the management, manipulation, analysis, modeling, representation, and display of geo- referenced data (With Latitude & Longitude) to solve complex and difficult problems regarding the planning and management of resources.

Ø  “A system for capturing, storing,  checking, integrating, manipulating, analyzing, 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”

It is set of

•         Collecting

•         Storing

•         Manipulating

•         Retrieving

•         Transforming and Display of Spatial  Data from the Real World

  GEOGRAPHIC: Geographic means that locations of the data items are known, or can be  calculated  in terms of Geographic coordinates (Latitude & Longitude).

 INFORMATION: It means that the data in a GIS are organized to gain useful  knowledge, often as color maps and images, but also as  statistical graphics, tables, and various on-screen responses to interactive queries.

 SYSTEM: System is that GIS is made up of several inter-related and linked components with various functions. Thus, GIS have functional capabilities for a group of data capture, input, manipulation, transformation, visualization, combinations, query, analysis, modeling and output.

Ø  Helps answer questions such as:

•         Where is it?

•         What else is nearby?

•         Where is the highest concentration of ‘X’?

•         Where can I find any objects with characteristic ‘Y’?

•         Where is the closest site ‘Y’ from my location?

GIS technology is attracted by a wide range of civil engineering disciplines owing to its potential to offer a new way of resolving environmental difficulties and problems which could reduce cost and time, support multi-discipline analysis and improve high quality for complex projects.

Ø COMPONENTS OF GIS

Ø HISTORY OF DEVELOPMENT

·     During the olden period 1854 cholera outbreak in London, English physician John Snow used points to represent the locations of many individual cases, possibly the earliest use of a GIS methodology in epidemiology. In his study of the distribution of cholera led to the source of the disease, a contaminated water pump (the Broad Street Pump, whose handle he had disconnected, thus terminating the outbreak) within the heart of the cholera outbreak.

·      This historical event became the arrival of the usage of spatial data for analysis and planning in many fields including Civil Engineering.

Ø GIS AREAS

GIS Software	Digital Image  Processing
ARC INFO	ERDAS Imagine
ArcGIS	ER Mapper
QGIS	ILWIS
MapInfo	ENVI
GRASS	PCI Geomatica
Geomedia	ArcView image analysis
Geoconcept	TNTMIPS
WIN GIS	Ecognition
Microstation
AutoCAD