Goals of Cartography and GI: Representation and Communication - A Primer of GIS: Fundamental Geographic and Cartographic Concepts - page 14

Image showing the results of stream
modeling combining a geographic representation of
events and their translation into the cartographic rep-
resentation of things.
From http://wwwbrr.cr.usgs.gov/projects/SW_Math_mod/
OpModels/MD_SWMS/Presentations/
Flood%20Inundation_files/v3_document.htm
marks to help people navigate who are unfamiliar with the roads and area.
Showing the things that are traffic jams is helpful for people visiting town,
but it may not be enough if you want to help someone coming into town at
5:00 P.M. find the best way to avoid known traffic jams to the best restaurant
on Main Street downtown. For this map, you need to show not only where
traffic jams occur but when they occur so that your visitor knows which roads
to take and which roads to avoid. It would be better for the purpose of guid-
ing your visitor to just show the traffic-jam events that can hinder his or her
trip to the restaurant. Showing too much information about attractions and
landmarks will probably be unnecessary for your visitor to find his or her
way.
Remember that things are static geographic information or map pat-
terns even though they can refer to a process such as too many vehicles trav-
eling at the same time. Animation techniques and dynamic GIS offer some
interesting possibilities to create dynamic cartographic visualizations that
show temporal changes. Geographic information analysis and geostatistics
provides a number of techniques for reliably representing processes (see
Chapter 13).
Abstraction and Reliability
Part of what makes representation difficult is that it simultaneously abstracts
while it attempts to assure reliability. Abstraction reduces complexity, or sim-
plifies, to highlight essential things, events, and relationships. Reliability is
the characteristic of a representation that refers to its dependability.
Representing things and events is complex because of the very nature of
abstraction. The world is theoretically infinitely complex: it is not possible