Some common GIS terminology
Before we dive-in, there are a few terms which you may not be familiar with:
Spatial : relating to 'space' or 'location'
Geospatial: Relating to location on earth, commonly used term to describe many GIS data and analysis
GPS: Global Positioning System, a satellite based system that gives accurate location information anywhere on earht.
How does GIS work?
The GIS workflow consists of following steps:
- Data Collection: To build any GIS, we need data. The data is collected, converted to a
convenient format and stored for use in subsequent processes.
- Example: If you are building a GIS Emergency Response, one needs data on road
networks in the city, location of hospitals/fire stations/police
stations, addresses of residents etc. Various tools such as GPS
devices, Aerial photos, Survey equipment etc. can be used for data
- Display and Analysis: The stored data is displayed and analyzed as per requirement. The data is
displayed on a computer screen and the operator gives commands to
- Example: To find the shortest route from a house to the nearest hospital, the operator analyzes using a
route finding algorithm on the roads data and the resulting path is
displayed on the computer screen. Many different types of data is
displayed as different layers and they are analyzed together.
- Sharing: The result of analysis needs to be shared with the decision maker for further action.
- Example: In emergency response, the shortest route found using analysis, can be
shared with the ambulance driver in form of printed or verbal
Majority time and effort in GIS is spent on collecting, formatting and storing
the source data. So it is important to understand the nature of the GIS
data and collection methods.
Two broad categories of GIS data are:
- Vector: In a GIS, real-world objects are represented using either points, lines or polygons.
- For example, a city's government may store the location of garbage
collection sites as points, roads as lines and property boundaries as
- Most commonly used data format for vector data is a shapefile . Other formats
- Raster: Raster data can be thought of as a photograph. Commonly used raster
data is aerial photos, satellite images, scanned maps and digital
elevation models. These 'pictures' can be called a GIS data source when
they contain information about the location - which part of the
real-world do they represent. Hence, the raster data formats allow for
storing real world coordinates of each pixel in the data.
- Most commonly used data formt for raster data is tiff/geotiff . Ohter formats
All GIS data, contains two-types of information - location
and information about the location
. So vector data will have coordinates ( location ) and attributes ( information about the location ).
- Example: A point data for a garbage collection site will have
- Coordinates - latitude and longitude of earth
- Attributes - zip code, pickup time etc.
Applications of GIS
- Emergency Response: GIS helps locate where help is needed and finding the shortest route for the responders to get there
- Utility: Power, Telecom, Oil and Gas companies use GIS to map and manage their networks.
- Urban Planning: Planners use GIS to monitor city growth and identify areas future development
- Insurance services: Insurance companies can process claims much faster and accurately, if
they have access to mapping data and geographical information. Buyers
benefits from reduced premiums and faster settlements
- Wildlife management: GPS tracking of animals to study their habitat and migration patterns.
GIS helps identify in wildlife conservation and optimal use of resources
- Healthcare: Using GIS one can identify a possible epidemic outbreak and take
preventive measures. Officials use GIS for planning healthcare
facilities that are accessible to more citizens.
- Marketing: Helps business sell and direct their products to the right market using GIS datasets and analysis tools
- Disaster relief: Remote Sensing, GIS and field GPS units can help locate victims and speed rescue efforts
- Tourism: First thing you do when travelling to a new place is to buy a map,
right? By using GIS and web-mapping services, tourism authorities,
travel agents, hoteliers and others can provide accurate and relevant
information to travellers
- Finding local information: people can search for local information, places to eat, shop and visit.
A GIS database enables searches like 'restaurant within 2 kms from here'
- Getting directions: Almost everyone in the western world would have used a direction
finding service. To find turn-by-turn directions to any place. These
online mapping services are powered by GIS technology.
- E-Governance: Land Information Systems, uses GIS to create and manage digital land
records. Governments all over the world use it to manage the land
parcel database. Citizens benefit by getting accurate, timely and easy
access to property information.
- Military/Defence: Remote sensing techniques have been used for decades for surveillance and reconnaisance.
- Agriculture: Surveying soil conditions, analysing crop patterns and using
GPS-enabled field instruments to better manage agriculture produce
- Real Estate: Developers benefit from getting quantitative information on market
needs and existing infrastructure. Agents use mapping services to help
clients find the right property by applying location constraints ( near
to school, within 15 minutes drive work work etc )
- Transport / Delivery services: Using live GPS tracking and GIS tools, companies can manage their fleet efficiently.
- Art: Artists can effectively combine spatial information and power of mapping to express emotions.
- Archaeology: Using spatial analysis techniques and visual interpretation of aerial
imagery, archaeologists can discover potential sites, and manage the
- Power: Electricity companies use GIS extensively in planning and managing their assets, laying networks and monitoring usage
- Hydrological Modeling: GIS adds spatial dimension to hydrological modelling and helps predict
water levels in rivers/lakes, rain water runoff, ground water
availability and better manage water levels.
Popular GIS Software
- ESRI Suite of Products - ArcInfo, ArcMap, ArcView, ArcSDE, ArcIMS, ArcGIS Explorer
- Autodesk Map
- Google Earth
- Plus many others...
Open-Source Software ( developed by volunteers, free of cost )
GIS Education and Employment
Education for GIS is generally offered by Universities, Colleges and Government
Organizations. GIS requires domain expetize in the application area,
along with technical expetise in GIS. Hence the courses offered in GIS
are also very diverse. There are following broad types of courses
- Certificate in GIS ( Diploma in GIS): short courses covering basic GIS techniques and knowledge of applications
- Executive programs: very short programs aimed at educating non-GIS executives on basics of GIS
- Masters/PhD in GIS: Advanced programs covering the broad range of applications as wells as in-depth knowledge on certain domains
GIS professionals come from a variety of backgrounds. Most commonly from
- Environmental Science
- Computer Science
Governments are generally the biggest employer of GIS professionals in a country.
Most GIS programs are directly or indirectly funded by government
efforts. Several other companies engage in consulting who provide
services to the private sector as well as to the government. Software
development companies also employ GIS professionals for development of
GIS software products.
GIS Employment falls in the following three broad categories:
- GIS Technician = Involves data conversion, digitizing, data processing
- GIS Analyst/GIS Specialist/GIS Consultant = Carrying out spatial analysis and data management
- GIS Developer = Software development, writing and testing code
GIS and Neogeography
Traidionally GIS has been a highly technical domain and it's usage has
been limited to technical experts. However, recently with the advent of
internet and freely available mapping applications has enabled a large
number of people to utilize GIS. Applications such as Google Earth
, Microsoft Virtual Earth
etc. enables non experts to use GIS for real-estate, insruance, media, archaeology, wildlife management and much more.