In general, a GIS provides facilities for datacapture, data management, data manipulation and analysis, and the presentation of results in both graphic and report form, with a particular emphasis uponpreserving and utilizing inherent characteristics ofspatial data.
An operational GIS also has a series of components that combineto make the system work. These components are critical to asuccessful GIS. A working GIS integrates five key components: HARDWARE, SOFTWARE, DATA, PEOPLE, METHODS
A GIS topology is a set of rules and behaviorsthat model how points, lines, and polygonsshare coincident geometry. Steps- arc node topology Area defination Adjacency
1. SPATIAL DATA- A- DISCREET DATA ( FEATURE BASE) B-CONTINUOUS DATA (GENERAL) A- RASTER DATAB- VECTOR DATAC- TIN DATA2. NON SPATIAL DATA- NOMINALDATA,ORDIANAL DATA,INTERVADATA,RATIO DATA, CARTOGRAPHICALDATA, NUMERIC DATA
GEOLOGICAL DATA SOIL DATA VEGETATION DATA LAND USE DATA WATER RESOURCES DATA LITHOLOGICAL DATA
DATA ACQUISITION PREPROCESSING DATA MANGEMENT MANIPULATION AND ANALYSIS PRODUCT GENERATION
Data acquisition is the process of sampling signalsthat measure real world physical conditions andconverting the resulting samples into digitalnumeric values that can be manipulated by acomputer. Sensors that convert physical parameters toelectrical signals. Signal conditioning circuitry to convert sensorsignals into a form that can be converted to digitalvalues. Analog-to-digital converters, which convertconditioned sensor signals to digital values
Analog-to-digital converter (ADC)- An electronicdevice that converts analog signals to an equivalent digital form.The analog-to-digital converter is the heart of most dataacquisition systems. Digital-to-Analog Converter (D/A) - An electronic componentfound in many data acquistion devices that produce an analogoutput signal. Digital Input/Output (DIO) - Refers to a type of data acquistionsignal. Digital I/O are discrete signals which are either one of twostates. These states may be on/off, high/low, 1/0, etc. Digital I/Oare also referred to as binary I/O.
Data pre-processing describes any type ofprocessing performed on raw data to prepare itfor another processing procedure.
A Database Management System (DBMS) is a set ofprograms that enables you to store, modify, and extractinformation from a database, it also provides users withtools to add, delete, access, modify, and analyse data storedin one location. A group can access the data by using queryand reporting tools that are part of the DBMS or by usingapplication programs specifically written to access the data. DBMS’s also provide the method for maintaining theintegrity of stored data, running security and users access,and recovering information if the system fails. Theinformation from a database can be presented in a variety offormats. Most DBMSs include a report writer program thatenables you to output data in the form of a report. ManyDBMSs also include a graphics component that enables youto output information in the form of graphs and charts.Database