Grade 9 Academic Geography – Strand 1 Maps Types of Maps In geography, maps are an important tool. Maps are used to examine the features of the Earth (natural or anthropogenic). In simple terms, maps are pictures of the Earth's surface. Maps show many things. They can be (1) general reference showing landforms, political boundaries, water, the locations of cities, etc., or (2) thematic maps showing specific features such as the average rainfall distribution, population density, distribution of a certain disease, etc. With computers, Geographic Information Systems (GIS) produce and update maps in almost real time, and allow you and I to track and interpret change more readily. Table 1. List of Some Map Types Map Type Description Bathymetric Navigational Shows the relief of the sea floor/lake floor Show the nature of the coasts, depth of water, etc. Cadastral Shows boundaries of landed properties, fields, buildings etc. Prepared by governments for revenue purposes Climate Shows information about the climate of an area generally based on temperature, precipitation or average number of cloudy days Normally use colours to show different climatic areas Economic or Resource Shows a specific type of economic activity or natural resources present in an area Uses different symbols or colours to represent different economic or resource features Example – Different agricultural products produced in Ontario with letters for natural resources and symbols for different industries Geological Show the rock formations, plus rock ages and structures, mineral resources, etc. Geomorphological Shows the Earth’s physical features, their relationship with land, water etc. Offers some conventional pictorial symbols to show relief, landforms etc. Political Does not show any topographic features Shows political boundaries of a place Shows locations of cities - both large and small, depending on the detail (i.e., scale) of the map. Example – Map of Canada showing the ten provinces and three territories, capital cities, major cities and international borders Physical Shows physical landscape features of a place such as mountains, rivers and lakes Water is always shown with blue. Mountains and elevation changes are usually shown with different colours and shades to show relief. Normally on physical maps, green shows lower elevations while browns show high elevations. Road Shows major and minor highways, roads, plus features such as airports, city locations, and points of interest like hospitals, parks, campgrounds and monuments. Thematic Topographic Illustrates a particular theme or special topic Different from other map types because they show themes in addition to natural features (e.g., rivers, cities, political subdivisions, elevation) which provide reference points. Example -- Population change of Canada in specific locations from 1996 to 2001 Shows different physical landscape features except they use contour lines instead of colours to show changes in elevation Contour lines on topographic maps are normally spaced at regular intervals to show elevation changes (e.g. each line represents a 30 m elevation change) and when lines are close together the terrain is steep Map Scale The scale of a map can be expressed as a RATIO (1:25 000), a STATEMENT (e.g., one centimetre equals 63 kilometres) or as a DIVIDED LINE SCALE noted in kilometres. Large-Scale Map A large-scale map could have a scale of 1:25 000 – the map shows one kilometre of the Earth’s surface in four centimetres OR the distance on the map is ONLY 25,000 X smaller than the actual distance it represents. Note: a great amount of detail can be shown on a large-scale map because it depicts only a small portion of the earth’s surface. Small-Scale Maps A small-scale map shows almost 30 000 000 km2 on the Earth’s surface inside a square with sides measuring only seven centimetres each. The scale for this map is 1:75 000 000. This is considered a SMALL-SCALE MAP because the distance on the map is 75 000 000 X smaller than the actual distance it represents. There is not much detail on a small-scale map. Small-scale maps are associated with HIGH numbers AFTER the colon (e.g., 1:1 000 000 and 1:16 000 000). To calculate scale as a ratio – 1. We have a map with a scale of 1:50 000. We measure the distance along a property boundary as 1.7 cm. What is the length in the real world? 0.85 km How? Map Scale = 1 50 000 Map Distance (MD) = 1.7 cm Actual Ground Distance (GD) = ? Map Scale = MD / GD If a distance of four centimetres on a map represents a distance of one kilometre on the ground, how many times longer is the kilometre than the four centimetres? A particular map shows a scale of 1:500 000. What would the map distance (in cm) be if the actual distance is 14 km? Ground Distance = 8.546 km and Map Distance = 36.5 cm. What is the scale?