Transcript Direct Statement and Line Scale and Representative Fraction

SCALE CAN BE SHOWN ON A MAP IN THREE WAYS
1. Direct Statement Scale – uses words to describe the relationship between a
distance on a map and a specific distance on the Earth’s surface
eg. 1 cm to 10 km. If we measure the distance between two places on a map and
the distance is 1 cm we know the actual distance between them is 10 km.
SCALE CAN BE SHOWN ON A MAP IN THREE WAYS
2. Line Scale
is like a special ruler that is divided into units of distance
Steps in using line scale:
1. Mark the locations of the two cities on the edge of a sheet of paper
2. Place the edge of the paper against the line scale with the first mark at 0
3. Make a mark on your paper at the right end of the scale
4. Move the mark from step 3 (above) to 0 on the on the line scale at measure the
remaining distance
SCALE CAN BE SHOWN ON A MAP IN THREE WAYS
3. Representative Fraction (R.F.) Scale – this is a ratio and is shown as 1:50 000. It
means that one unit on the map represents 50 000 of the same units on the
Earth’s surface. The units may be in centimeters or inches.
Eg. If the R.F. is 1:50 000 then 1 cm on the map represents 50 000 cm on the
Earth’s surface.
SCALE CAN BE SHOWN ON A MAP IN THREE WAYS
To convert an R.F. to a direct statement scale, divide the denominator by 100 000, to change
the centimeters into kilometer.
Eg. R.F. 1:50 000 is
1 cm = 50 000 cm
1 cm = (50 000 / (divided by) 100 000) km
1 cm = 0.5 or 1 cm to 500 m ( half a km)
To convert Direct Statement Scale to R.F. Scale, multiply the number of kilometers by 100
000
Eg. Convert the direct statement 1 cm to 2.5 km into a representative fraction:
1 cm = 2.5 km
1 cm = (2.5 x 100 000) cm
1 cm = 250 000 cm or 1:250 000