Ordnance Survey Maps

Can anyone remember what OS maps are?

Keywords

1. Scale2. Grid Reference3. Slope4. Legend/ key5. Settlement

Ordnance Survey MapsWe 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 DistancesWhat 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!

ActivityUsing 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 – LetterE – EastingN - Northing

Q

R

Easting

No

R

T

H

I

N

G

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 10lines.

Class Activity: Ballina OS map pg 172.

4 figure grid reference: Cloonah Lough. Carvan and camping park.

6 figure grid referenceTourist information siteMoated siteStanding stoneHospital.

Today’s Class• Measuring area

Calculating AreaFrom your maths course what is area?

To calcluate the area of a rectangular area 1. Count the number of squares across2. Count the number of squares up3. 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 ClassSymbols 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 - .5673. 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. Even2. Concave 3. Convex slope4. 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

SettlementWhat 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!!!