World Topography

Second only to climate as a conditioner of human activity--particularly in agriculture and in the location of cities and industry--is topography or terrain. It is what we often call "landforms." A comparison of this map with the map of land use (Map 6) will show that most of the world's productive agricultural zones are located in lowland regions. Where large regions of agricultural productivity are found, we tend to find urban concentrations and, with cities, industry. There is also a good spatial correlation between the map of landforms and the map showing the distribution and density of the human population (Map 7). Normally, the world's landforms shown on this map are the result of extremely gradual primary geologic activity, such as the long-term movement of crustal plates (sometimes called continental drift). This activity occurs over hundreds of millions of years. Also important is the more rapid (but still slow by human standards) geomorphological or erosional activity of water, wind, and glacial ice; and waves, tides, and currents. Some landforms may be produced by abrupt or cataclysmic events, such as a major volcanic eruption or a meteor strike, but these are relatively rare and their effects are usually too minor to show up on a map of this scale.