|
LD811 - Geography 1A - PRACTICAL EXERCISE 1
Topography means, in the original Greek, the description of a place. A map is a drawing to illustrate such a description ... Topographical maps show the natural features of the country, hills and rivers, forests and swamps; and in addition such artificial features as man [sic] has added to the country in the shape of towns villages; roads, railways and canals; bridges and telegraphs. From Hinks (1947) cited in Biddle, Milne and Shortle (1974) The Language of Maps, Jacaranda Press, Melbourne, page 10. IntroductionTopographic maps are the most widely used of all maps. They depict the relief or shape of the ground usually by means of contour lines. They also show other natural features (eg. rivers, lakes, etc). Geographers need to be able to read and interpret topographic maps, as they frequently use these to find their way in the field and as a base on which to record geographical information. The various symbols used on any map should be explained in the legend or key. Other information which must be shown includes:
1.The direction of north,
indicated by an arrow (the direction of magnetic north may also be given).
2.The scale of the map (usually expressed as a ratio, graphically as a numbered bar or often both). 3.The contour interval (vertical difference between adjacent contours). 4.The type of map projection (normally transverse mercator). NB: Maps are a two dimensional projection of a three dimensional surface. 5.The reliability (given on a small diagram which shows the relative reliability of methods used in different areas of the map). It is also essential to have a map title. Other useful information which may be given includes: a locality or index map (showing the general location); the compilation (name of person who compiled the map and date); and a co-ordinate system.
|
