UNDERSTANDING MAPS Geographical Data Skills (Part 1)
What are maps? ◦ Maps are pictures or graphical representations of all or a part of the Earth’s surface and its features. ◦ Examples of maps: ◦ Atlas ◦ World map ◦ Street directory ◦ Dot maps ◦ Isobars, Isotherms, contour maps, etc
Functions of Maps ◦ Different types of maps would represent different data variables, or perspectives of the map-maker. ◦ For example, all maps of the world will be distorted to a certain degree, depending on their intended use.
Functions of Maps Standard World Map (Mercator Projection)
Functions of Maps Peters Projection
Different Types of maps Dot Density maps The features of a polygon theme are displayed with a number of dots corresponding to a value. Used for: Showing how particular things are distributed throughout an area
Different Types of maps Topographic maps Shows the shape and elevation of terrain. Used for: To understand the earth’s terrain To plan routes and buildings To establish evacuation routes and flood control maps. For hazard mapping.
Different Types of maps Remotely sensed images Geographic information gathered by means of a sensor. The common remote sensing images include aerial photographs, radar images, and satellite images. Used for: These images are important sources for producing digital maps and are useful for monitoring environmental changes and human activities.
Names of Features Scale Symbols and Legends Directional Indicator Grid Lines Title Names of Features Scale Names of Features Scale Key Parts of a Map
Title ◦ The title of the map states what the map shows ◦ It usually appears on top of the map ◦ On topographical maps, the title is usually the name of the largest settlement on the map
Name of Features ◦ Features include: ◦ Roads ◦ Settlements ◦ Rivers ◦ Naming them helps us to identify these features.
Scale ◦ The scale shows the size of the map as compared to the actual size of the area that the map represents. ◦ Purpose: ◦ Allows the user to calculate exactly how big or small a features is on the earth’s surface.
Grid Lines ◦ Grid lines are a series of numbered vertical lines drawn on a map. ◦ They are used to locate features on a map.
Directional Indicator ◦ It shows where ◦ North ◦ South ◦ East ◦ West lies North (Never) East (Eat) South (Sour) West (Watermelon)
Symbols and Legends ◦ Symbols are used to represent the different physical or man- made features found on the surface of the Earth. ◦ Symbols are used because it is possible to fit a lot of information into a small space. ◦ Legend lists all the symbols used in the map and explains what each of them mean or represent.
READING TOPOGRAPHIC MAPS
Measuring Distance ◦ A scale can be shown on a map in 3 ways: ◦ As a statement ◦ As a representative or fraction ◦ As a line or linear scale 1 cm represents 2 km 1:200000
Measuring Distance (cont) ◦ Measuring a straight line: ◦ Use a ruler to measure the length between two points. ◦ Use the scale of the map to find out the actual distance on the ground. ◦ Eg if the scale of the map is 1:10000, then a length of 1cm on the map is equivalent to 10000cm(0.1km / 100 metres)
Measuring Distance (cont) ◦ Measuring distance along a curve ◦ Place one end of the string at the starting point. Hold this end down firmly with your finger. ◦ Use the string to follow the path with your fingers slowly. ◦ When you reach the end, use a pencil to mark the string. ◦ Remove the string and measure the distance against a ruler. ◦ Use the scale to convert the length to actual distance on the ground.
Finding Location Atlas/World MapsTopographical Maps Longitudes/Latitudes Grid references
Locations in a topographic map can be found using grid references. ◦ There are basically 2 types of grid references ◦ Four figure grid references ◦ Six figure grid references Finding Location (Topo Map)
Finding Direction ◦ Cardinal Points are points marked on a compass. ◦ Besides the basic North, South, East, West, there are additional points marked North East, South East, South West, North West. N SW SE NE WE S NW
Finding direction using cardinal points. ◦ Find the direction of Y from X ◦ Draw a line joining the two places or feature ◦ Draw a mini vertical and horizontal line, which intersects at X ◦ Look at X and use one of the cardinal points to describe the position of Y from X.
Bearings (Angles!) ◦ Measure the bearing of B from A ◦ Draw a line to join the two points ◦ Place the protractor at A. The 0° on the protractor must point to North ◦ The point on the outer edge of the protractor where the line joining A and B crosses show the bearing of B from point A.
QUICK ACTIVITY! READ: Pages TRY: Pg of your Geography Skills book Q1-4