Map Skills

[Music] this Jim and Bill are doing a homework assignment for geography they've made a good start in working the problems but some of the questions require more information than they've been able to find Jim has read through many pages of his text without much success perhaps the information he needs can be found on a map knowing how to read maps and how to use different Maps together can provide you with information that might not be found in dozens of pages of written text these two maps of North America are similar to those the boys are using only they are of the same projection and are drawn to the same scale one map is a physical map showing elevation the other map shows average annual range rainfall Let's examine the rainfall map more closely three levels of rainfall are shown light moderate and heavy we can move the area showing light rainfall onto the physical map this shows us that rainfall is light in the western Plateau Basin and Mountain areas now we'll bring in the the part of the rainfall map showing moderate rainfall this Falls primarily in the Interior Lowlands the portion showing heavy rainfall Falls over lowland areas and over coastal areas that are bordered by warm ocean currents it appears that large bodies of water and the elevation of the land are factors which help to influence the amount of rainfall the boys can discover additional Relationships by using other kinds of maps together this one shows natural vegetation using a similar map we can show how three kinds of vegetation trees grass and desert plants are related to other natural features of the continent we're moving in the portion of the rainfall map showing light rainfall this portion fits mostly over Desert Shrub and short grasses the portion showing moderate rainfall Falls primarily over tall grasses and forests heavy rainfall is associated with the remaining forested lands the maps show a close relationship between rainfall and natural vegetation now let's compare the rainfall map with another map showing kinds of farming much cotton is grown in regions of heavy rainfall corn farming and dairying occur in regions of moderate rainfall while wheat farming and livock grazing are carried on in the area marked by light rainfall going to the physical map once again helps us see that the elevation and Contour of the land are also related to various kinds of farming cotton farming is carried on in areas of heavy rainfall and level land we can understand why when we remember that level land permits the use of farm machinery in harvesting the cotton heavy rainfall provides the moisture needed to grow this crop corn requires somewhat less moisture and so may be grown in regions of moderate rainfall again level land makes mechanization possible wheat is commonly grown in areas with still less moisture again level land makes it possible to use heavy machinery in regions of light rainfall which are hilly or mountainous it is difficult to use machinery for cultivating and harvesting crops but grass will grow here providing ing food for livestock on Mountain slopes where there is more rain trees will grow providing wood for lumber and Paper Industries in moist areas which are too hilly for the growing of field crops fruit trees can be raised so there are relationships among crops rainfall and the Contour of the land the boys are finding other relationships by using Maps together this map shows the location of coal deposits in North America if we add to it a map of iron or deposits we arrive at a composite map showing important resources for industry adding a third map of the major industrial areas of the continent shows us that there is a fairly close relationship ship among Industries coal and Iron Coal and iron ore are the raw materials for the production of Steel it seems reasonable that steel mills would be found where these materials are readily available steel is the most widely used of All Metals finished steel of many grades and forms is used in producing machines appliances and other manufactured products this helps explain why factories tend to be located near sources of coal and iron ore what other factors are related to Industrial Development adding water routes and railroads to the map helps us see that the location of Industries particularly heavy Industries is related to water and rail transportation raw materials must be transported from their source to a factory finished products must be carried from a factory to the ultimate consumer the availability of transportation that is fast or cheap can determine whether it is practical to manufacture a certain kind of goods in a given area what other relationships can the boys discover by using different Maps together remember this map of major railroads and waterways we'll compare it with a map showing population distribution and major cities of North America these are social and political features now look at this map again maps are not always found together in books so it's a good idea to learn to combine them in your mind look again at the population map then the other back and forth until you can combine them like this now you see a relationship between the two maps the density of population is greatest in areas where there is good Transportation historically where there has been good transportation and where a change in transportation is made as from ships to railroad cars in these areas large cities have developed large cities have also grown near natural resources where industry might develop industry and transportation have made possible intensive use of the land providing the materials necessary to support a large population and many people in turn have provided the human resources needed to run the stores and offices and other services essential for continued growth the political growth of Nations can be seen with the help of historical Maps this one shows the political boundaries of the United States in 1810 as we move to 1835 we see how political units multiplied and spread Westward continued change in growth are seen as we move to 1855 on to 1912 and finally to the present day when we need a different map to show all 50 states with the help of many different maps maps showing natural features of the Earth maps showing human use and maps showing social and political features the boys have been able to finish their homework assignment as you continue your study of geography you'll find many other ways of using different Maps together to understand how man has been influenced by his physical environment and how man in turn is changing his environment for his own [Music] use