Ordnance Survey Maps
Can anyone remember what OS
maps are?
Keywords
1.
2.
3.
4.
5.
Scale
Grid Reference
Slope
Legend/ key
Settlement
Ordnance Survey Maps
We will learn how to
1. Use scale.
2. Measure straight and curved lines.
3. Write grid references.
4. Tell direction.
5. Read height and slope on a map.
6. Draw a sketch map.
7. Calculate area.
8. Use a legend/key.
9. Learn about settlement.
What does an os map look like?
Why is an OS map so small?
• Remember that a map is a picture of a much
larger area of land. In order to be useful, a map
must be small enough to fit into someone’s
hands.
• A full-size map of the Earth would be too large to
make.
• Maps are scaled down so that they fit on the
available paper or screen.
Scale
Scale is the relationship between a distance
on a map and the distance on the ground.
Scale on OS map = 1:50,000
1cm on the map = 50,000cm (500m) on the
ground (in real life!)
Class Activity:
1. What would 1km on the ground be in cm on the map?
2. Look at the examples of an OS map. Find the scale.
Make 3 observations about the scale.
Direction
• North South East and West – Easy!!
• Can you remember all the other
directions??
Measuring Distances on maps
1. Measuring straight line distances (‘as the
crow flies’).
2. Measuring curved line distances e.g.
roads, railways and rivers.
Straight Line Distances
What you need – piece of paper folded over.
pencil
scale ( on the OS map!!)
1. Fold over a piece of paper.
2. Put the edge of the paper at the start point and
place the other edge at the other point. Mark
the paper at both edges.
3. Using the scale measure the difference
between the two marks.
4. Remember use km!
Activity
Using the OS maps pick any two points and
measure the distance!
Help each other!
Curved Line Distances
• Lay a piece of folded over paper at the starting
point and mark with a pencil.
• Keep moving the paper around the curved line..
Every time the road curves move the paper.
• Mark the end point on your paper and use the
scale to measure the distance of the line.
Activity
• Using the OS map measure the following
curved line distances!
Today’s Class
• Grid References
Grid References
What do you remember
about grid references
from last year?
Remember L.E.N
L – Letter
E – Easting
N - Northing
N
o
Q
R
T
R
H
I
N
G
Easting
Grid References
• Four figure grid references – for a single
square on the map. S40 52
• Six figure grid references – for an exact
location of small features. S401 528
Can anyone remember what you have to do to get
a 6 figure grid reference?
6 Figure Grid Reference
Use LEN but…. To get 6 figures you need to divide the boxes into 10
lines.
Class Activity: Ballina OS map pg 172.
4 figure grid reference:
Cloonah Lough.
Carvan and camping park.
6 figure grid reference
Tourist information site
Moated site
Standing stone
Hospital.
Today’s Class
• Measuring area
Calculating Area
From your maths course what is area?
To calcluate the area of a rectangular area
1. Count the number of squares across
2. Count the number of squares up
3. Multiply the two numbers and make sure
to use km squared.
Calculating Area
•
To calculate area of an irregularly
shaped area e.g. sea
1. Tick all the squares that are fully covered
with the sea.
2. Tick any boxes that are more than half
covered with the sea
3. Add the two numbers together.
4. Make sure to use km2
Activity
• Calculate the area of the Ballina map on
page 172.
• Calculate the area of the Cork map on pg
176.
• Calculate the area of Lough Mahon on pg
176.
Today’s Class
Symbols and the legend
Height on OS maps
Slope
Sketch maps
Symbols
• The best thing about the symbols on an OS
map is that you don’t have to learn them off
by heart!!
• They are all on the legend/key at the back
of the map.
Let’s look at the map of Cork.. Can you
guess what the symbols are without looking
at the legend.
Height on OS maps
•
4 ways to show height
1. Triangle with a number next to it.
2. Spot Height - .567
3. Contour lines – line joining places of equal
height. Close contours = steep slope.
4. Colour layers – green = low ground
brown = high ground.
Slope
Contour lines show what type of slope is
present. There are 4 types
1.
2.
3.
4.
Even
Concave
Convex slope
Compound slope.
Activity
• Draw the table into your copies. Use the
full A4 page.
• Use colour to help you remember which
ones are which.
Activity 2: What slope am I?
Test each other.
Drawing a sketch map
• In groups try to remember how we drew
sketch maps last year.
Remember we did this
last year!
Today’s Class
• Settlement – Rural & Urban
Settlement
What do you think
settlement means?
Hint:
Settlement: Place where people
live!
Keywords
• Ancient settlement:
• Rural Settlement
• Urban Settlement
Density of settlement
• The number of houses per square
kilometre (km²)
• Houses on OS maps are shown as black
dots
City: High density
Countryside: Low density
RURAL SETTLEMENT
•
Some factors attract people to settle in a
particular area, whereas some factors stop
people from settling in an area.
Can you think of any?
•
•
Altitude—People want to live in lowland
areas.
Shelter—The foot of hills and mountains or
valley floors provide shelter from the elements.
• Aspect – South facing to get the most
sunshine
• Drainage—people settle in well drained
land
• Slope – Settlement tends to avoid steep
sloping areas because it is difficult to farm
and construct roads. Also lowland areas
have better soil for farming !
Settlement patterns
• Linear or Ribbon
• Clustered or Nucleated
• Dispersed or Scattered
Activity
• Using the OS maps find the different
patterns of rural settlement.
Urban Settlement: Where do towns
develop?
• On flat or gently sloping lowlands
• Transport construction is easier, Building is easier and
land is better (Agriculture)
• Where roads or other transport routes
meet (Nodal/Focus Point)
• At such places, people meet, trade develops and
settlement grows
• At Bridging points of rivers
• Where bridges exist, roads usually meet and towns develop
• Rivers were very important (Water supply, food, Transport and
Defence)
• At coastal locations
•
Many towns developed as trading or fishing ports
• Historical Influences
• Many towns developed as a result of Castles, Monasteries
etc. (Protection)
Urban Functions
• Towns have many
functions or uses.
Towns often have
many functions. Can
you think of them?
Urban Functions
• Look at the functions on page 143.
• Read as a group.
Activity: Make a list of the functions in
Carrick on Suir.
End of Chapter!
But don’t worry we will
be seeing much more
of OS maps for the rest
of the year!!!