An isoline map is a map with continuous lines joining points of the same value. Examples would be equal altitude (contour lines), temperature (isotherms), barometric pressure (isobars), wind speed (isotachs), wind direction (isogon), wind shear (isoshear), etc. Isoline mapping is used to interpret the information on some thematic maps.
Flow maps in cartography are a mix of maps and flow charts, that "show the movement of objects from one location to another, such as the number of people in a migration, the amount of goods being traded, or the number of packets in a network".
Proportional symbol maps scale the size of simple symbols (usually a circle or square) proportionally to the data value found at that location. They are a simple concept to grasp: The larger the symbol, the "more" of something exists at a location. The default setting in indiemapper is to scale the circles directly proportionate to the data (the "unclassed" tab) so that if, for example, Toronto has twice the population of Vancouver, the population symbol for Toronto will have twice the area. However, in indiemapper you can also group your observations into categories or numerical ranges (the "classed" tab) and created graduated symbol maps that may, for example, only have three symbol sizes corresponding to three categories of city size (e.g., cities of <1 million, 1-4 million, and over 4 million people). The pros and cons of proportional versus graduated symbols are discussed in more detail below.
How to measure distance on a map
- Find the scale for the map you're going to use - it might be a ruler-looking bar scale or a written scale, in words or numbers.
- Use a ruler to measure the distance between the two places. If the line is quite cureved, use a string to determine the distance and then measure the string.
- If the scale is a representative fraction (and looks like 1/100,000 or 1:100,000), multiply the distance of the ruler by the denominator, giving distance in the ruler units.
- If the scale is a word statement (i.e. "One centimeter equals one kilometer") then determine the distance.
- For a graphic scale, you'll need to measure the graphic and divide the scale into the measured units on the ruler.
- Convert your units of measurement into the most convenient units for you (i.e. convert 63,360 inches to one mile)
How to measure direction on a map
The top of a map shows the north direction, while the bottom of the map shows the south direction. Towards the right is the east and the west lies towards the left in an atlas.
The point between the north and the west is the north-west, while the point between the north and the east is the northeast. The direction between the south and the west is called East the south-west, while the direction between the south and the east is called the south-east. you must note that north or south is said first and not west or east. So the intermediate points are NW, NE, 5W and 5E.
Sometimes a place may not be exactly in these four directions. We can mark other directions, say midway between north and east. It is called north-east, Thus we can also mark south-east north-west and south-west, These are called sub-directions.
4 and 6 Figure Grid references
For a 4 figure grid reference you look at the numbers which are in the bottom left of the square. For a 6 figure grid reference, you should split the square into 100 smaller ones. Then add numbers 1 to 10 between the main lines.To work out the 6 figure grid reference, first go along the bottom line and calculate the first 3 figures. Then do the same but going up the line.