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We have tried to include examples from all the areas in which GIS is currently actively employed
GIS technology, data structures and analytical techniques are gradually being incorporated into a wide range of executive and decision-making operations.
Numerous examples of applications of GIS are available in many different journals and are frequent topics of presentations at conferences in the natural and social sciences
In order to understand the range of applicability of GIS it is necessary to characterize the multitude of applications in some logical way so that similarities and differences between approaches and needs can be examined
An understanding of this range of needs is critical for those who will be dealing with the procurement and management of a GIS
Mature technologies which interact with GIS, sharing its technology and creating data for it
- surveying and engineering
- cartography
- remote sensing
Cartography
- there are two areas of GIS application in cartography:
1. mechanization of the map-making process
2. fabrication of new forms of maps resulting from investigation, manipulation of data
- the second is closer to the concept of GIS even though both use similar technology
Computers in cartography
- first efforts to automate the map-making process occurred in early 1960s
- major advantage of automation is in ease of editing
- objects can be moved around digital map without redrafting
- scale and projection change are relatively easy
- differences between automated mapping and GIS are frequently emphasized
- mapping requires: knowledge of positions of objects, limited number of attributes
- GIS requires: knowledge of positions of objects, attributes, relationships between objects
- hence distinction between "cartographic" and "topological" databases
- "analytical" cartography involves investigation of mapped data
- has much in common with some aspects of GIS analysis
- cartography plays a vital role in the success of GIS
- supplies principles of design of map output products - how to make them easy to read and interpret?
- represents centuries of development of expertise in compiling, handling, displaying geographical data
- widespread feeling that conversion to digital technology:
- is inevitable
- will change the field through new techniques
Surveying
- surveying is concerned with the measurement of locations of objects on the Earth's surface, particularly property boundaries
- all 3 dimensions are important - vertical as well as horizontal positions
- the locations of a limited number of sites are fixed extremely accurately through precision instruments and measurements
- these sites are monuments or benchmarks - the geodetic control network
- this is the function of geodesy or geodetic science
- using these accurate benchmarks for location, large numbers of locations can then be accurately determined relative to the fixed monuments
- surveying is an important supplier of data to GIS
- however, it is not directly concerned with role of GIS as a decision-making tool
- some civil engineers now use GIS technology, especially digital elevation models and associated functionality, to assist in planning construction
Remote sensing
- like surveying, is a data producing field
- acquires knowledge about the Earth's surface from airborne or space platforms
- elaborate, well-developed technology and techniques
- instruments for data capture - high spatial and spectral resolution
- transmission of data, processing, archiving
- interpreting and classifying images
- two major roles for GIS concepts:
- quality and value of product is enhanced by use of additional data to improve accuracy of classification
- to be useful in decision-making, product needs to be combined with other layers less readily observed from space
- example: political boundaries
- remote sensing continues to be an dynamic research area
- new instruments need to be evaluated for applications in different fields
- careful research is needed to realize the enormous potential of the technology
- volume of accumulated data is increasing rapidly
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