Introducing Geographic Information Systems with ArcGIS: A Workbook Approach to Learning GIS, 3rd Edition

GIS and Cartography—Compatibility?

Earlier, in Chapter 2, we discussed the differences between maps and GIS. Here I want to illustrate a dramatic, seldom recognized difference between published maps and GIS-developed maps. It turns out that, no matter how good the tools in GIS become in facilitating the production of paper maps, there is a fundamental incompatibility between GIS data and even a fairly large-scale paper map. In addition to the previously discussed advantages of GIS over maps is the fact that cartographers sometimes have to distort the positions of features in order to let the map convey important information. For example, suppose that in a mountainous region there is a populated valley. Running through this valley may be several linear features: a stream, a road, a power line, a gas main, and a railroad track. These elements may have to exist within a corridor only a couple of hundred feet wide. Further, the road may cross the stream and the railroad. A distance of 250 feet translates to only an eighth of an inch on one “2000-scale map,” where 1 inch corresponds to 2000 feet. (The scale is 1:24000 – a standard scale for US topo maps.)

An eighth of an inch certainly does not supply enough space to show these features and the relationships between them. If the symbols for these features are shown in their correct spatial locations, they will appear on top of each other. What is the cartographer to do? Fudge! Widen the valley and exaggerate the distances between the ...