Geographic information science is the science underlying geographic concepts, applications, and systems. GIS can refer to a number of different technologies, processes, information system in organization pdf methods.
GIS can relate unrelated information by using location as the key index variable. This key characteristic of GIS has begun to open new avenues of scientific inquiry. 1968 in his paper “A Geographic Information System for Regional Planning”. Tomlinson is also acknowledged as the “father of GIS”. This was one of the earliest successful uses of a geographic methodology in epidemiology. John Snow map was unique, using cartographic methods not only to depict but also to analyze clusters of geographically dependent phenomena.
When all the layers were finished, they were combined into one image using a large process camera. Once color printing came in, the layers idea was also used for creating separate printing plates for each color. Canada, by the federal Department of Forestry and Rural Development. A rating classification factor was also added to permit analysis.
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. The CGIS was never available commercially. GIS software, successfully incorporating many of the CGIS features, combining the first generation approach to separation of spatial and attribute information with a second generation approach to organizing attribute data into database structures. This began the process of moving GIS from the research department into the business environment. Several articles on the history of GIS have been published.
Modern GIS technologies use digital information, for which various digitized data creation methods are used. CAD program, and geo-referencing capabilities. Just as a relational database containing text or numbers can relate many different tables using common key index variables, GIS can relate otherwise unrelated information by using location as the key index variable. Any variable that can be located spatially, and increasingly also temporally, can be referenced using a GIS. Related by accurate spatial information, an incredible variety of real-world and projected past or future data can be analyzed, interpreted and represented. GIS accuracy depends upon source data, and how it is encoded to be data referenced. Web technology are changing the quality, utility, and expectations of GIS to serve society on a grand scale, but nevertheless there are other source data that affect overall GIS accuracy like paper maps, though these may be of limited use in achieving the desired accuracy.
A quantitative analysis of maps brings accuracy issues into focus. The electronic and other equipment used to make measurements for GIS is far more precise than the machines of conventional map analysis. All geographical data are inherently inaccurate, and these inaccuracies will propagate through GIS operations in ways that are difficult to predict. Points, lines, and polygons are the stuff of mapped location attribute references. GIS thematic maps then are becoming more and more realistically visually descriptive of what they set out to show or determine.
Data capture—entering information into the system—consumes much of the time of GIS practitioners. There are a variety of methods used to enter data into a GIS where it is stored in a digital format. This has been enhanced by the availability of low-cost mapping-grade GPS units with decimeter accuracy in real time. This eliminates the need to post process, import, and update the data in the office after fieldwork has been collected. New technologies also allow users to create maps as well as analysis directly in the field, making projects more efficient and mapping more accurate.