There are five essential components which make a complete Geographic Information System. Even imagine about GIS is not possible if we remove one of these components. All components are important (however some may be more some may be less). These are-
A robust computer system is must for smoothly performing all the operations required in GIS. We can divide hardware in two categories- essential and optional. The essential hardware includes Computer monitor, CPU, keyboard and mouse. This is the basic requirement to start working in GIS. Optional hardware includes- printer, plotter, scanner, projector etc. It is good to have optional hardware also but only if your budget permits, otherwise these can be outsourced. Apart from these one should have storage and data transfer devices also, like- CDs (for transferring & storing data which is small in volume), DVDs (for larger data sets), pen drive, external hard disk etc.
GIS software provides commands, tools and functions for storing, capturing, processing, analyzing and displaying GIS data. There is lot of options available in market (like- ArcView/ ArcEditor/ ArcInfo by ESRI, MapInfo, GeoMedia, Manifold etc.). One should go for the GIS software which can provide complete solution. It may be costly at initial stage but is a good investment in long term. Good GIS software provides:
~Import & export options of industry standard formats like- ESRI shape files, MapInfo files, image files, database files, AutoCAD drawings, etc.(these are only few examples).
~Georeferencing and projection conversion tools.
~GPS support (to download & upload way points, tracks, maps etc.) for standard GPS instrument like that from- Garmin, Trimble, Leica, Magellan etc.
~Data Analysis tools for- spatial analysis, geostatistical analysis, 3-D analysis (terrain modeling), network analysis etc.
~Raster support with basic image processing tools.
~A number of layout and map preparation options.
~Support to display layouts & maps properly; and also to export these for further use in non-GIS platforms (like making presentation in Microsoft PowerPoint).
The above mentioned list may not be complete; it is just for giving a broad idea about GIS software (Some tools may be included or some may be excluded from this list).
Data is the most important component of GIS. The final GIS output largely depend on the availability and quality of the data (If you want to cook a healthy and tasty food then good quality vegetables and grains should be available to you with a lot of varieties!). The input data for GIS may be in the form of- satellite images, scanned maps, survey data, historical records, topomaps, spreadsheets etc.
There are a lot of methods used in GIS. Which methodology is to follow is solely depends upon the kind of GIS assignment to be done. There are some generalize and standard methods used in GIS. However, it may be needed to develop and customize your own methods to get desired output. Whatever methods one uses, it is necessary to do planning for each and every step. A well-defined and carefully selected methodology (according to our requirements) always saves time, resources and money; and gives good results.
It is people for & by whom GIS is developed. There are lot of people who are directly or indirectly remain involved in it – GIS managers (to manage and plan whole GIS task), GIS specialist (to perform GIS related operations), surveyors, data collectors, database administrators (to maintain & manage GIS database), programmers (to customize GIS software), end users and decision makers.