Climate is average whether condition of given area recorded over very long period of time. Topographic map show little direct evidence of climatic condition. yet by looking at certain evidences one is able to describe the climate of the given mapped area. The description of climate in topographic map bases on two element of climate namely temperature and rainfall since their variation can easily explained by various evidence from the map.
Some hints in interpreting climate from topographic map:
- Latitude of the area. latitude are the angular distance of a place north or south of the earth’s equator, or of a celestial object north or south of the celestial equator, usually expressed in degrees and minutes. Through studying latitude one is able to deduce the climatic condition of given mapped area. For example the area with latitude 5 degrees north or south of equator the area is considered to be in equatorial climatic condition while the area between 5 to 15 degrees north or south of equator is in tropical climatic condition.
- Presence of water bodies and drainage pattern. A general high density of streams indicate that the area receive high rainfall. in another case the presence of low density, intermittent or seasonal streams, salt lakes and boreholes indicate aridity.
- Vegetation, presence of forest in the map indicate heavy rainfall while woodland vegetation indicate moderate rainfall. shrubs, thickets and grassland indicate dry condition or light rainfall
- Crops, crops grows in those areas where water and temperature conditions are favorable for their growth.For example area with tea, coffee and sugar cane indicate that area receives heavy rainfall. Crops such as cotton, sisal and sorghum indicate medium rainfall
- Relief/altitude, altitude of features such as high mountain or mountain ranges and plateaus tend to have orographic rainfall and forest making them make their own mountainous climate. Mountains do also create their own climate due to effect of aspect which create rain shadow