Ordnance Survey (O.S.) maps show areas of Ireland in great detail divided into a grid system with lettered squares and surrounding numbers called Eastings and Northings. The maps also include a key showing map symbols. Grid references in either four or six figures are used to locate features on maps. Calculating areas involves counting squares, while sketch maps are simplified versions of O.S. maps including a frame and key showing selected features to scale. Rural settlement patterns are affected by height, slope, aspect and drainage, resulting in dispersed, nucleated or ribboned housing configurations. Urban settlement develops in flat, accessible locations at river crossings or coasts where roads intersect and trade can occur.

1. Ordnance Survey Maps
Ordnance Survey maps
These are called O.S. maps for short. They show areas in great detail- 1cm = 1 km. On
all OS maps there is a scale bar.
Ireland is divided up into a grid system called the National Grid. This grid is made
up of 25 lettered squares. Each square has a letter, therefore ALL OS maps contain a
letter.
The National Grid is surrounded by numbers, therefore ALL OS maps are
surrounded by numbers.
The Vertical numbers are called Eastings.
The Horizontal numbers are called Northings.
OS maps also have what is known as a KEY or Legend. This shows symbols for
features on a map.
Grid References
Grid references are used to help give locations of features on OS maps. There are Two
types.
 Four-figure Grid References
 Six-figure Grid References
Four figure Grid Refs. Give an approx. location, while Six figure Grid Refs. Give an
exact location.
Remember the word- ATLAS

2. Across Top L Along Side
(don’t forget the letter!)
Four Figure Grid References
Rules for giving a Four-fig Grid Reference-
1. Give the Letter (If there are two, make sure you have the right one!)
2. (Across the top) What box is your feature in?
3. (Along the Side) What box is your feature in?
Six Figure Grid References
Rules for giving a Six-fig Grid Reference-
4. Give the Letter (If there are two, make sure you have the right one!)
5. (Across the top) What box is your feature in?
6. How far across the box is your feature? (1-9)
7. (Along the Side) What box is your feature in?
8. How far up the box is your feature? (1-9)
Calculating area on a map
Each square on an OS map is 1km x 1km (1km²)
In order to calculate a regular area we must multiply the amount of squares across
the base by the amount of squares up along the side. (Example- 7 squares x 8 squares
= 56km²)

3. Tocalculate an irregular area, for example a lake, we simply count the number of
squares that are at least half full of water. Again we give our answer in km².
Choosing a location for a new factory
1. Beside a main road. (For Lorries coming in and out)
2. Beside a large town (for workers, and a market to sell your product)
3. On Flat land (easy tobuild on)
4. Beside an Airport, Port or railway station (to transport your product)
Drawing Sketch Maps
Sketch maps are simplified versions of OS Maps. On sketch maps you are expected to
include 5 or 6 items or features. Sketch maps should also include a KEY. A key
basically tells us what each feature is.
Rules for Sketch maps
 The Frame must be the same SHAPE as the OS map you are using.
 Draw FOUR lines for your frame. DO NOT use the edge of the page as one. Make
them dark to stand out.
 Always use pencils and colouring pencils. Never pen or marker.
 At the top of the page write what area the map is from. Eg. Killarney area.
 Always leave space for your Key. Do not squash it in.
 Keep your features to scale and in the right place.
 Make the features on the map the exact same as they appear in your Key.
 ONLY PUT DOWN WHAT YOU ARE ASKED. DO NOT CLUTTER YOUR MAP
Rural Settlement
Rural means Countryside. (The opposite is Urban, which means towns/cities)

4. Settlement means where people live.
There are FOUR factors that affect where people build houses in the country.
Height. People rarely build up in the mountains. Too windy, no shelter, poor roads,
feel cut off
Slope. If the land is too steep it is difficult to build on.
Aspect. This is the direction that the sun shines. People will build where their house
gets most sun.
Drainage. People will not build where it is too wet. Eg. Too close to a river, the sea or
at the bottom of a steep slope.
Settlement Patterns
There are three types of settlement patterns.
DISPERSED (SCATTERED)This is when the houses are very far apart. Eg. Out in the
country (farms), on high ground.
NUCLEATED (CLUSTERED) This pattern is when there are many houses bunched
together. Eg. at a cross roads.
RIBBONED (LINEAR) This is when there are a row of houses built in a line along a
road.
Urban Settlement
This is towns and cities. There are many reasons why towns and cities develop at
their locations.

5. 1. Flat land It is easy to build on flat land. It may be good farming land and
people may have settled there in order to buy/sell vegetables etc.
2. Where roads meet Towns develop where many roads meet. This is where a
lot of people would gather to buy/sell and meet up with each other.
3. On a River Most towns are built on rivers. Rivers would have been useful
for water, food and transport. Towns are normally located at a low point of the
river where it is easy tocross.
4. At the coast Some towns develop near the sea because of fishing
(Killybegs) or Tourism (Bundoran)