GIS and Its Components.pptx

Defination of GIS and its Components.

1. Geographic Information Systems (GIS) store, analyze, and visualize data for geographic positions on Earth’s surface. GIS stands for  Geographic Information Systems  and is a computer-based tool that examines spatial relationships, patterns, and trends in geography . G IS "A Geo Information System is a system for capturing, storing, checking, integrating, manipulating, analysing, and displaying data which are spatially referenced to the Earth. ( P.Stefanovic )

2. C omponents of G IS

3. A GIS is an organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information.   Hardware Hardware is the computer on which a GIS operates. Today, GIS software runs on a wide range of hardware types, from centralized computer servers to desktop computers used in stand-alone or networked configurations . Motherboard:  It is board where major hardware parts are installed or It is a place where all components gets hooked up. Hard Drive:  It is also called hard disk,  place to store data. Processor:  Processor is the major component in computer, it performs calculation. It is called as Central processing Unit (CPU). RAM:  Random Access Memory (RAM) where all running programs load temporarily. Printer:  It is output device and used to print image, map or document. There are various type of printer available in market. External Disk:  These are portable storage space such as USB drive, DVD, CD or external disk. Monitor:  It is a screen for displaying output information. Nowadays there are various type of monitor: CRT (cathode ray tube), LCD (Liquid Crystal Display), LED (Light Emitting Diodes) and more.

4. Software GIS software provides the functions and tools needed to store, analyze, and display geographic information. It helps to query, edit, run and display GIS data. It uses RDBMS (Relational Database Management System) to store the data. Few GIS software list: ArcGis , ArcView 3.2, QGIS, SAGA GIS . S oftware Components : GIS Tools:  Key tools to support the browsing of the GIS data RDBMS:  Relational Database Management System to store GIS data. GIS Software retrieve from RDBMS or insert data into RDBMS. Query Tools:  Tools that work with database management system for querying, insertion, deletion and other SQL (Standard Query Language). GUI:  Graphical User Interface that helps user and Software to interact well. Layout:  Good layout window to design map.

5. Data Possibly the most important component of a GIS is the data. Geographic data and related tabular data can be collected in-house or purchased from a commercial data provider. A GIS will integrate spatial data with other data resources and can even use a DBMS, used by most organizations to organize and maintain their data, to manage spatial data . The data that a GIS operates on consists of any data bearing a definable relationship to space, including any data about things and events that occur in nature.  At one time this consisted of hard-copy data, like traditional cartographic maps, surveyor’s logs, demographic statistics, geographic reports, and descriptions from the field.  Advances in spatial data collection, classification, and accuracy have allowed more and more standard digital base-maps to become available at different scales . Data are two types- Spatial and Non spatial. Spatial Data  Vector Vector data is graphical representations of the real world. There are three main types of vector data: points , lines , and polygons. Connecting points create lines, and connecting lines that create an enclosed area create polygons.

6. Point Data- Data points, also known as data items, are the atomic state of data. Conceptually, you can think of them as one cell in a data table, or one piece of information, about an observation, at a given point in time . Line Data- Line (or arc) data is used to represent linear features. Common examples would be rivers, trails, and streets. Line features only have one dimension and therefore can only be used to measure length . Area Data- Area data is used to represent polygon features. Common examples would be forest, agricultural land, water body. Polygon features have two dimension and therefore can be used to measure area.

7. Raster Raster data  is data that is presented in a grid of pixels. Each pixel within a raster has a value, whether it be a colour or unit of measurement. This communicates information about the element in question. Rasters typically refer to imagery. However, in the spatial world, this may specifically refer to  orthoimagery  which are photos taken from satellites or other aerial devices. Raster data quality varies depending on resolution and your task at hand. Attribute data  are non-spatial characteristics that are connected by tables to points, lines, “events” on lines, and polygons (and in some cases GRID cells)A point, vector or raster geologic map might describe a “rock unit” on a map with a single number, letter or name, but the associated attribute table might have age lithology percent quartz etc , for each rock type on the map . Data Possibly the most important component of a GIS is the data. Geographic data and related tabular data can be collected in-house or purchased from a commercial data provider. A GIS will integrate spatial data with other data resources and can even use a DBMS, used by most organizations to organize and maintain their data, to manage spatial data . People GIS technology is of limited value without the people who manage the system and develop plans for applying it to real-world problems. GIS users range from technical specialists who design and maintain the system to those who use it to help them perform their everyday work.