Introduction to Geographic Information SystemsGeographic Information Systems (GIS) are a combination of computer hardware, software, and procedures designed to support the capture, management, analysis, modelling and display of geographically referenced data. GIS combines database management with automated mapping in order to represent and model the real world. Geographic Information Systems can be used to analyse problems, such as: identifying all buildings which would be affected by flooding up to a given elevation; determining the most cost effective route for bus transport within a city; assessing the areal extent of the most fire-susceptible timber within a forest management area; determining the location and characteristics of a market for a particular product, assessing and determining the locations of areas with high mineral potential, land uses, and areas of possible landuse conflict. Geographic Information Systems for commercial use were developed in the 1980's. The advent of powerful and relatively low-cost computers in the mid-to-late 1980's resulted in greater access to previously specialized software and data from large mainframe computers. In the 1990's, the trend has been towards the use of 'Desktop-GIS' at a cost similar to other business/professional software. In the first 10 years of the millenium there continues to be a trend towards higher processing and memory capability in the technology along with a parallel evolution in GIS and related applications. The internet has provided greater networking, data access, distributed processing, and embedded mapping applications. | Feature Video: G-I-YES!GIS ComponentsData Input: Converts the data from an existing form into one which can be used by a GIS in a digital format. The data may be captured in either a vector format or in a raster format. This may be accomplished through manual digitizing, scanning, or from existing digital data. Data Management: These are the functions performed by a Geographic Information System to store and retrieve data from the database. This capability is similar to that provided by database management software. The data are entered into a pre-defined structure which may or may not be inter-related. Data Manipulation and Analysis: These functions may vary from one GIS to another but can be broadly sub-divided into spatial vs. non-spatial analysis. Spatial analysis requires knowledge of the geographic relationships between the data (points, lines, and polygons) contained in the GIS; non-spatial analysis represents a query of the database similar to those functions in database management software. Generally, a GIS with advanced spatial analysis capabilities requires more processing time and more memory storage capacity than those without. Data Output: The GIS has to output the data in the form of maps, tables, and text either as softcopy (on-screen or electronic file) or as hardcopy (paper or film). In considering a GIS it is important to assess the quality, accuracy, and ease of use for the output. Generally, vector-based systems can produce higher quality map output than raster-based systems. |
