Change is constant and as a result everything around us is continuously evolving. GIS is no exception here. Over a period of twenty-five years, GIS professionals have seen this technology evolve from command line, workstation-based stand-alone software to geospatial tools that can now be used in the cloud and via mobile devices and affecting day to day life of a common man.
What is GIS?
The is the most asked question specially to those who are working this field and at times it is the hardest one to answer in a clear and concise manner.
GIS allows us to capture, store, query and analyze spatial and non-spatial data to address real-world problems. Basically, GIS is nothing but an information system with spatial (or say geographic) context. It supports capturing location/area/route of feature along with its details popularly known as attribute data of the feature.
What is Spatial Data?
Location information of a feature is called spatial data. Every feature can be captured in any one of the three basic geometry that is Point, Line and Polygon.
A feature with relatively small size and almost nil width and length are captured with Point geometry. In the backend X and Y coordinates are stored in the database. A feature with long length but zero width is stored with series of connected X and Y coordinates while forming a Line geometry. Similarly, a feature with large width and length forming close boundary is stored with series of X and Y coordinates while forming Polygon geometry.
What is Attribute Data?
Combination of spatial and non-spatial data (attribute data) enables GIS to address various complex real-world problems which are otherwise almost impossible to handle.
Attribute data is nothing but additional information about each feature. For example, name of the road, height of the building or population of a country are attributes of respective features. Here spatial data and attribute data are linked with a uniqueID and normally have one-to-one relationship. These uniqueID and relationships are generally maintained by the GIS software.
What are the components of GIS?
There are five critical components of GIS system: Hardware, Software, Data, People and Procedures
Hardware
Hardware includes computer system and equipment required for data capturing, data storage, data publishing and analysis. GIS data is normally stored in a high-performance central servers and users access these data from Desktop, Web and Mobile platforms. GIS is a specialized software and so it requires higher processing power with large amount of storage capacity. The use of handheld field devices like GPS and mobile is becoming popular for various data collection and analysis purpose.
Software
There are variety of GIS software available in the market. They start from free open-source software to commercial packages. Software varies based on their functional capability and capacity to manage large volume of data and growing userbase. One must choose the software that is best suited to meet the functional and performance requirements of the users. While ESRI ArcGIS is the most famous commercial software package, QGIS is also very popular open-source software product. Software products are designed for meeting most of their requirement through default functionality requiring little bit configuration. GIS software also support customization to meet specific requirement. Third party extensions and add-ons are used to extend the capabilities of the default package.
Data
Data is backbone of entire GIS system and plays major role in successful GIS implementation. Data creation, data cleansing and day to day updating forms the most time and resource consuming task of any GIS implementation. Like any other information system, GIS operates on GIGO principle that is Garbage-In-Garbage-Out. In other words, quality of analysis and results largely depends on the quality of data.
There are primarily two types of data, Raster and Vector data. Raster data is like photographs where in information is stored in the pixel value. Pixel value can be as simple as RGB value or any other information which is changing continuously over the area of interest. For example, satellite image of a city is a raster data. Vector data is used to represent discrete information having strict boundary. For example, state boundary, road network, airport premises etc.
People
GIS is a niche field and experts are in scarcity. A well-trained GIS professional with spatial thinking ability and working knowledge of operating popular GIS software are essential for GIS implementation. There is no specific qualification requirement for building career in GIS. One can build career in GIS while applying a right combination of fundamental classes supported by GIS internship and participating in workshops and conferences.
Procedures
Successful GIS implementation requires systematic efforts. A set of standard operating procedures must be established which can ensure that quality of data is in line with functional and performance requirements of the end users. People must be educated on the procedures and their role in GIs system through various training and awareness workshops.
What are the applications of GIS?
GIS is applicable to almost all real-world problems that is having relation to the location on the earth surface. At the most basic level, GIS is used as a cartographic tool for making meaningful maps and conveying meaningful messages. I am sure you know that map is a new language for communicating information.
The real strength of GIS is utilized through its spatial and statistical methods for analyzing spatial and attribute data. Spatial representation of the data provides a new innovative way of looking at the data which is otherwise not available with rows and columns of spreadsheets.
Some of the questions that GIS system can answer are:
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- Which is the nearest petrol pump shop from my location (proximity analysis)?
- Where to setup a tower for highest network coverage (hill-shade analysis)?
- Which route I should follow to cover maximum collection points in shortest time (network analysis)?
- Location within cities delivering highest revenue (hotspot analysis)?
