A Geographical Information System (GIS) deals specifically with geographic (or spatial) information, rather than other types of data (such as financial or personnel). These are represented as different layers where each layer holds data about a particular type of feature. Each feature is linked to a geographic position.
The term "GIS" is perhaps a loose one (although first coined by pioneering Canadians) since:
GIS resulted from the need to OVERLAY different map layers: early cited example of the Irish Railway Atlas (1850)
GIS grew from Cartography: there is a close inter-relationship between (digital) cartography and GIS, within Geomatics
At UNBC, this is reflected in the links between GEOG205 (Cartography and Geomatics) and GEOG300
Many standard GIS operations were previously conceived and executed on analogue maps (e.g. calculating slope from contours). Conversely, many users adopt GIS primarily to make maps, either standard mapping products or to illustrate the results of GIS analysis. Example: Manitoba Geological Survey gallery
The prime differences between a GIS and a mapping system are in their functional components:
A GIS contains these four components:
This difference is best shown in a software query that lists element attributes
...in other words, a cartographic query gives information on design features (ii above), while a GIS query yields details or parameters about the features themselves, where the data are stored in a GIS database (B. above). We can't "ask" a cartographic map to display where forest cover is "spruce" and average tree height is 50 metres. However, we can ask a GIS the same question and it will display where the query is true.
GIS software must have these four components:
a. Means of data input
b. Database management system (DBMS)
c. Analysis capability
d. Graphics output
Related types of mapping software may have some but not all of these capabilities:
* GDS usually do not include 'Spatial geo-referencing' (see lecture 3)
Each of these may perform better than a GIS at their specialty, but only a GIS has all four components:
e.g. mapping software may be better for map production, databases for database management ..
WHAT IF ..? -
Examples : "What would happen to the view if we harvested 10 ha of trees from the valley "
What if the climate warmed by 2 degrees? (effect on habitats) Prince George example