Some common GIS terminology

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 GPSdevices, Aerial photos, Survey equipment etc. can be used for datacollection
• 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 perform analysis.
• • 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 isdisplayed 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 instruction.

GIS Data

Majority time and effort in GIS is spent on collecting, formatting and storingthe source data. So it is important to understand the nature of the GISdata 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 polygons.
  • Most commonly used data format for vector data is a shapefile . Other formats[1]
    
• 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 whenthey contain information about the location - which part of thereal-world do they represent. Hence, the raster data formats allow forstoring real world coordinates of each pixel in the data.
  
• • Most commonly used data formt for raster data is tiff/geotiff . Ohter formats[2]
    

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[3]

1. Emergency Response: GIS helps locate where help is needed and finding the shortest route for the responders to get there
2. Utility: Power, Telecom, Oil and Gas companies use GIS to map and manage their networks.
3. Urban Planning: Planners use GIS to monitor city growth and identify areas future development
4. 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
5. Wildlife management: GPS tracking of animals to study their habitat and migration patterns. GIS helps identify in wildlife conservation and optimal use of resources
6. 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.
7. Marketing: Helps business sell and direct their products to the right market using GIS datasets and analysis tools
8. Disaster relief: Remote Sensing, GIS and field GPS units can help locate victims and speed rescue efforts
9. 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 relevantinformation to travellers
10. 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'
11. 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.
12. 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 easyaccess to property information.
    
13. Military/Defence: Remote sensing techniques have been used for decades for surveillance and reconnaisance.
14. Agriculture: Surveying soil conditions, analysing crop patterns and using GPS-enabled field instruments to better manage agriculture produce
15. 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 ( nearto school, within 15 minutes drive work work etc )
16. Transport / Delivery services: Using live GPS tracking and GIS tools, companies can manage their fleet efficiently.
    
17. Art: Artists can effectively combine spatial information and power of mapping to express emotions.
18. Archaeology: Using spatial analysis techniques and visual interpretation of aerial imagery, archaeologists can discover potential sites, and manage the excavations.
19. Power: Electricity companies use GIS extensively in planning and managing their assets, laying networks and monitoring usage
20. 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

Commercial Products

• ESRI Suite of Products - ArcInfo, ArcMap, ArcView, ArcSDE, ArcIMS, ArcGIS Explorer
  
• Mapinfo
• Autodesk Map
• IDRISI
• Google Earth
• Plus many others...

Open-Source Software ( developed by volunteers, free of cost )

• GRASS
• Mapserver
  
• ILWIS
• A complete list at http://freegis.org/[4]

GIS Education and Employment[5]

Education

Education for GIS is generally offered by Universities, Colleges and GovernmentOrganizations. GIS requires domain expetize in the application area,along with technical expetise in GIS. Hence the courses offered in GISare 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

• Geography
• Environmental Science
• Engineering
• Computer Science
  

Employment

Governments are generally the biggest employer of GIS professionals in a country.Most GIS programs are directly or indirectly funded by governmentefforts. Several other companies engage in consulting who provideservices to the private sector as well as to the government. Softwaredevelopment companies also employ GIS professionals for development ofGIS 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[6]

Traidionally GIS has been a highly technical domain and it's usage hasbeen limited to technical experts. However, recently with the advent ofinternet and freely available mapping applications has enabled a largenumber 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.