FUNDAMENTALS OF GEOINFORMATICS PART-II (CLASS: FYBSc SEM- II) UNIT:-I: INTRODUCTION TO GIS 1.1.Definition, Potential of GIS, Concept of Space and Time 1.2.Components of GIS, Evolution/Origin and Objectives 1.3.History of GIS INTRODUCTION:- A G I S is a computer system that can store virtually any information found on a paper map. But it can be much more helpful than a traditional map. Whereas the G I S can display maps on a computer screen, it can also provide detailed information about their features. Including roads, buildings, streams, and so forth. Moreover, the computer can quickly search and analyze these map features and their attributes in ways that are not possible with paper maps. A geographic information system (GIS), geographical information system, or geospatial information system is the system that captures, stores, analyzes, manages, and presents data with reference to geographic location data. In the simplest terms, GIS is the merging of cartography, statistical analysis, and database technology. Therefore, in a general sense, the term describes any information system that integrates stores, edits, analyzes, shares, and displays geographic information for informing decision making. GIS applications are tools that allow users to create interactive queries (user-created searches), analyze spatial information, edit data, maps, and present the results of all these operations. Geographic information science is the science underlying the geographic concepts, applications and systems. Why is GIS unique? GIS handles SPATIAL information - Information referenced by its location in space GIS makes connections between activities based on spatial proximity WHAT IS GIS? A Geographic Information System (GIS) is a computer-based tool for mapping and analyzing things that exist and events that happen on earth. GIS technology integrates common database operations such as query and statistical analysis with the unique visualization and geographic analysis benefits offered by maps. These abilities distinguish GIS from other information systems and make it valuable to a wide range of public and private enterprises for explaining events, predicting outcomes, and planning strategies.
SOME COMMON DEFINITIONS ARE: 1. Geographical Information System is a computer based tool for mapping and analyzing the natural and human induced matter that things existence on the earth 2. Burrough (1986):- "Set of tools for collecting, storing, retrieving at will, transforming and displaying spatial data from the real world for a particular set of purposes." 3. Arnoff (1989):- "A computer based system that provides four sets of capabilities to handle geo-referenced data: Data Input Data Management (data storage and retrieval), Data Manipulation & Analysis and Data output. 4. Cowen (1988):- A decision support system involving the integration of spatially reference data in a problem solving environment. 5. ESRI (Environmental Systems Research Institute):- "In the strictest sense, a GIS is a computer system capable of assembling, storing, manipulating, and displaying geographically referenced information, i.e. data identified according to their locations. Practitioners also regard the total GIS as including operating personnel and the data that go into the system." GIS Objectives:- Maximise the efficiency of planning and decision making. Provide efficient means for data distribution and handling. Elimination of redundant data base minimise duplication. Capacity to integrate information from many sources. Complex analysis/query involving geographical referenced data to generated new information. For any application there are five generic question a GIS can answer: Location : What exists at a particular location? Condition : Identify locations where certain conditions exist. Patterns : What spatial pattern exists? Modeling : What if?
THE NEED FOR GIS: Any organization, government private is in some way or another strongly linked to the geography in which it operates. A GIS that has been designed in a proper manner has the capability of providing quick and easy access to large volumes of data of these geographical features. The user can access & select information by area or by theme to merge one data set with another, to analyze spatial characteristics of data, to search for particular features, to update quickly and cheaply and asses alternatives. In simpler terms, GIS allows the user to understand geographic information in an easy manner without having to go through large volumes of confusing data that is in tabular form. Visualizing the geography of a particular location is no doubt easier that trying to analyze raw data. The potential and important benefits of using GIS make it a very important tool making the work of any organization easier and more productive. Some of the potential benefits of GIS are: Opportunity to reduce sets of manual maps held and associated storage costs. Faster and more extensive access to geographic information. Improved analysis e.g.of areas, distances, patterns, etc. Better communication of information to public officers, members. Improved quality of services. Better targeting and coordination of services. Improved productivity in providing public information. Improved efficiency in updating maps. The ability to track and monitor growth and development over time. Improved ability to aggregate data for specific sub areas.
Concepts of Space and Time (in Spatial Information Systems):- Spatial information is always related to geographic space, i.e., large-scale space. This is the space beyond the human body, space that represents the surrounding geographic world. Within such space, we constantly move around, we navigate in it, and we conceptualize it in different ways. Geographic space is the space of topographic, land use/land cover, climatic, cadastral, and other features of the geographic world. Geographic information system technology is used to manipulate objects in geographic space, and to acquire knowledge from spatial facts Geographic space is distinct from small-scale space, or tabletop space. In other words, objects that are smaller than us, objects that can be moved around on a tabletop, belong to smallscale space and are not subject of our interest. The human understanding of space, influenced by language and cultural background, plays an important role in how we design and use tools for the processing of spatial data. In the same way as spatial information is always related to geographic space, it relates to geographic time, the time whose effects we observe in the changing geographic world around us. We are less interested in pure philosophical or physical considerations about time or space-time, but more in the observable spatio-temporal effects that can be described, measured and stored in information systems COMPONENTS OF GIS: It must be first understood that GIS is Not Software, rather it is a System. This system comprises of Software, Hardware, Data, and users that make it possible to enter, manipulate, analyze, and present information that is tied to a location on the earth s surface. The components of GIS fall into four main categories: 1. Data: Data is one of the most important, and often most expensive, components of a GIS. All data in a GIS are either Spatial data or Attribute data. Spatial data tells us where something occurs. Attribute data tells what occurs; it tells us the nature or characteristics of the spatial data. Fortunately, much of the data GIS users need has been created by government agencies or commercial operations, and is available for free or for purchase from the data providers. GIS uses Relational Databases to store and manipulate attribute data. 2. Users: The final component required for a true GIS is users. The term "user" may refer to any individual who will use GIS to support project or program goals, or to an entire organization that will employ GIS in support of its overall mission. GIS users are often envisioned as hands-on computer processing people. While this is in part true, often a broader spectrum of GIS users is chosen. One classification scheme (USGS, 1988) classifies users into three groups: System user s End Users Data Generators
3. Methods: A successful GIS operates according to a well-designed plan and business rules, which are the models & operating practices unique to each organization. There are various techniques used for map creation & further tor any project. The map creation can either be automated raster to vector creator or it can be manually vectorised using the scanned images. 4. Hardware: Hardware is the computer on which a GIS operates. The software runs on a wide range of hardware types, from centralized computer servers to desktop computers used in stand-alone or networked configurations. It also includes the hardware that we use to provide Input to the GIS. For Example: Scanners, Computers, Keyboards, and Satellites etc. 5. Software: Software is also a highly dynamic part of the system. Dozens of GIS software packages now exist. These systems are available on many different types of hardware platforms and come with a wide variety of functional capabilities. Origins of G I S:- G I S was pioneered in the 1960s by the Canadian forestry mapping initiative and continued to develop as Canadian, U.S. and other government and university researchers sought to represent the earth s geography using a computer terminal, and plot it on paper. They also developed computer programs to quickly search and analyze this data. Several corporation were founded in the 1970s to develop and sell systems for computer mapping and analysis. The Environmental Systems Research Institute (ESRI) of Redlands, California, focused on providing a tool kit of computer commands for the analysis of G I S data. History of development:- In 1854, John Snow depicted a cholera outbreak in London using points to represent the locations of some individual cases, possibly the earliest use of the geographic method. His study of the distribution of cholera led to the source of the disease, a contaminated water pump (the Broad Street Pump, whose handle he had disconnected, thus terminating the outbreak) within the heart of the cholera outbreak. E. W. Gilbert's version (1958) of John Snow's 1855 map of the Soho cholera outbreak showing the clusters of cholera cases in the London epidemic of 1854 While the basic elements of topography and theme existed previously in cartography, the John Snow map was unique, using cartographic methods not only to depict but also to analyze clusters of geographically dependent phenomena for the first time.
The early 20th century saw the development of photolithography, by which maps were separated into layers. Computer hardware development spurred by nuclear weapon research led to general-purpose computer "mapping" applications by the early 1960s. The year 1960 saw the development of the world's first true operational GIS in Ottawa, Ontario, Canada by the federal Department of Forestry and Rural Development. Developed by Dr. Roger Tomlinson, it was called the "Canada Geographic Information System" (CGIS) and was used to store, analyze, and manipulate data collected for the Canada Land Inventory (CLI) an effort to determine the land capability for rural Canada by mapping information about soils, agriculture, recreation, wildlife, waterfowl, forestry, and land use at a scale of 1:50,000. A rating classification factor was also added to permit analysis. CGIS was the world's first such system and an improvement over "mapping" applications as it provided capabilities for overlay, measurement, and digitizing/scanning. It supported a national coordinate system that spanned the continent, coded lines as "arcs" having a true embedded topology, and it stored the attribute and locational information in separate files. As a result of this, Tomlinson has become known as the "father of GIS," Particularly for his use of overlays in promoting the spatial analysis of convergent geographic data. CGIS lasted into the 1990s and built a large digital land resource database in Canada. It was developed as a mainframe based system in support of federal and provincial resource planning and management. Its strength was continent-wide analysis of complex datasets. The CGIS was never available in a commercial form. In 1964, Howard T Fisher formed the Laboratory for Computer Graphics and Spatial Analysis at the Harvard Graduate School of Design (LCGSA 1965-1991), where a number of important theoretical concepts in spatial data handling were developed, and which by the 1970s had distributed seminal software code and systems, such as 'SYMAP', 'GRID', and 'ODYSSEY' - - which served as literal and inspirational sources for subsequent commercial development to universities, research centers, and corporations worldwide. ************************