Object Representation / Symbolisation.

Topographic Map Symbolisation

Topographic maps use a wide variety of symbols to represent man made and physical features, for example highways, railroads, gravel pits, buildings, etc. Ideally, all these features should appear on a map in their true proportion, position, and shape. This is however, still not feasible because many of the features would be unimportant and others would be unrecognisable because of their reduction in size. Furthermore, some symbols have to be created to represent the man-made and natural features. These symbols are as closely as possible to the real features themselves. If this is not possible, a new symbol is created that logically implies the feature(s) it portrays. For example, a campsite is represented by a small black triangular tent. Symbols are positioned on a topographic map in such a manner that the centre of the symbol remains its true location. However, an exception to this would be the position of a feature adjacent to an important road. If the width of the road has been exaggerated, then the feature is moved from its true position to preserve its relation to the road.

Remark: All the methods and rules to resolve symbolisation problems are described in the lesson Generalisation.

Topographic Map Colours

Topographic maps use standardised cartographic conventions to represent features. Therefore, the following colours will still represent the same feature groups on topographic maps:

• Black: Man-made or cultural features, such as roads, buildings, names, boundaries, and transmission lines.
• Blue: Water or hydrographic features, such as lakes, rivers, canals, glaciers, and swamps.
• Brown: Contour lines, which show relief, but also terrain variation.
• Green / White: Landscape cover.
• Red: Important roads.
• Yellow: Secondary roads.