Page 71 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

Chapter 1 essentials of Geography 35
Topographic base
Parcels
Zoning
Floodplains
Wetlands
Land cover
Soils
Survey control
Composite overlay of all data layers
(b) Land-cover map of British Columbia created using GIS
(a)
▲Figure 1.31 A geographic information system (GiS) model. (a) layered spatial data in a GIS format. (b) This biogeoclimatic map of British Columbia is a valuable tool for forestry management in the province. [(a) After USGS. (b) © Province of British Columbia. All rights reserved. Reprinted with the permission of the Province of British Columbia, www.cio.gov.bc.ca/cio/intellectualproperty/index.page.]
A GIS is capable of analyzing patterns and relation- ships within a single data plane, such as the floodplain or soil layer in Figure 1.31a. A GIS also can generate an overlay analysis where two or more data planes interact. When the layers are combined, the resulting synthesis—a composite overlay—is ready for use in analyzing complex problems. The utility of a GIS is its ability to manipulate data and bring together several variables for analysis.
One of the most extensive and longest operating systems is the Canada Geographic Information system (CGIS). Roger Tomlinson (1933–2014), a Canadian geogra- pher recognised as the father of GIS (see Royal Canadian Geographic Society award at www.rcgs.org/awards/gold_ medal/winner_gold2003.asp), was key in the development of the Canadian GIS. To create the system, environmental data about natural features, resources, and land use were taken from maps, aerial photographs, and orbital sources, reduced to map segments, and entered into the CGIS. The development of this system has progressed with the ongoing Canada Land Inventory project; to acquire CLI data visit the web page at geogratis.gc.ca/geogratis/ DownloadDirectory.
Geographic information science (GISci) is the field that develops the capabilities of GIS for use within ge- ography and other disciplines. GISci analyzes Earth
and human phenomena over time. This can include the study and forecasting of diseases, the population dis- placement caused by Hurricane Sandy, the destruction from the Japan earthquake and tsunami in 2011, or the status of endangered species and ecosystems, to name a few examples. GIS can be used in conjunction with GPS for applications such as precision agriculture men- tioned earlier in this chapter.
One widely used application of GIS technology is in the creation of maps with a three-dimensional per- spective. These maps are produced by combining digital elevation models (DEMs), which provide the base eleva- tion data, with satellite-image overlay (see examples in Chapter 13). Through the GIS, these data are available for multiple displays, animations, and other scientific analyses.
Google EarthTM and similar programs that can be downloaded from the Internet provide three- dimensional viewing of the globe, as well as geographic information (earth.google.com/). Google EarthTM allows the user to “fly” anywhere on Earth and zoom in on landscapes and features of interest, using satellite im- agery and aerial photography at varying resolutions. Users can select layers, as in a GIS model, depending on the task at hand and the composite overlay displayed.