|Geoscience and Environment|
Project focusThis project addresses the following question: How might a Geographical Information System (GIS) support the study of sea level change?
On the basis of this project, GIS has revealed the advantages listed below, most of which relate to increased precision.
1. Use of digital elevation models (DEMs)
Use of digital elevation models (DEMs)
DEMs are inherently more precise than contour maps though their accuracy depends on many factors, including the source of the data and how it was processed. The data used for this project is called ETOPO 5 and was obtained from the National Geophysical Data Center (NGDC).
DEMs are more flexible than contour maps because it is possible to make new contours at any interval within the elevation range, which is essential for modeling.
Improved method for combining layers of dataBuilding maps with several layers can be done manually using color transparencies. Combining map layers with GIS is more precise, more flexible, and cheaper. Using IDRISI it was easy to show the coastlines of Sundaland with a very precisely drawn vector layer, something that would have been difficult to do by hand. A GIS is more precise because registration can be exact. It is more flexible since the data can be manipulated to produce a greater variety of layers. It is cheaper because costly printouts are not needed for intermediate steps, thus the cost of amendments is the labor cost alone.
Increased efficiency in processing graphical input and outputs
The movie depicting the cyclical rise and fall in sea level was easy to make using IDRISI. However, making such a movie manually would have been such an inefficient use of time that I would not have attempted it.
Facility for modelling earth processes
GIS is suited to a quantitative and statistical approach to earth science. While this project is a very simple application of GIS, it does illustrate that GIS can be used to model earth processes, which is the most significant result.
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