Transcript Slide 1

Grid & Area References
• It can be difficult to find places or features easily on a
map.
•
Topographic maps are large scale and we use these for
Area and Grid references
So how do we locate features on
a Topographic map?
•
http://news.bbc.co.uk/2/hi/uk_news/wales/north_west/7824895.stm
• This BBC link details the importance of Grid References
for emergency services to reach rural areas.
• We can locate places easily on a topographic map by
using the maps gridlines.
• On a topographic map the vertical (
)lines are
called eastings because they increase in value as we
move eastward.
• The horizontal (
) lines are called northings
because they increase in value as we move northwards.
18
17
16
N
15
Northings
22
23
24
Eastings
25
26
27
Area Reference
• Features such as a small lake, quarry or village
are usually located by means of an Area
Reference (AR)
• To find the (AR) of a feature we use the
coordinate in the lower left-hand corner of the
grid square in which the feature is located.
• You always read the easting first then the
northing. (hint to remember E comes before N in
the alphabet)
• An area reference always has 4 figures
• Into the house and up the stairs” may help you
remember!!
EXAMPLE: AR3363
easting
northing
The Area
Reference of
the house is:
18
AR2317
Remember with
(AR) you use the
bottom left hand
corner
17
What is the
(AR) for:
The plane:
AR2215
16
The boy:
N
AR2316
15
Northings 22
23
24
Eastings
25
26
27
Area references
Time now for a little test. FOUR squares are going to be highlighted and you
have TEN seconds to write down the area reference for each square.
39
A
38
10
9
8
7
6
5
4
3
2
1
37
A
36
35
21
22
23
24
25
26
CLICKfor
to
CLICK
start.....
the
next
square
Area references
39
A
38
10
9
8
7
6
5
4
3
2
1
37
B
B
36
35
21
22
23
24
25
26
CLICK for
the next
square
Area references
39
A
38
10
9
8
7
6
5
4
3
2
1
37
C
B
36
C
35
21
22
23
24
25
26
CLICK for
the next
square
Area references
39
A
38
10
9
8
7
6
5
4
3
2
1
D
37
D
B
36
C
35
21
22
23
24
25
26
CLICK for
the next
square
Area references
A = 2238
B = 2536
39
A
C = 2235
38
D = 2337
D
37
B
36
C
35
21
22
23
24
25
26
CLICK
How did
youTO
get on?
CHECK EACH
ANSWER
Grid References
• We can locate relatively small and more specific features
on map by using Grid Reference (GR).
• (GR) locates the exact point on the grid.
• Unlike (AR), Grid Reference uses 6 figures.
-The first two numbers of each coordinate refers to the eastings and
northings that surround the map.
- The third number needed to complete each coordinate is obtained by
dividing each easting and northing into tenths.
Dividing the easting and northing into
tenths
Example: GR335638
easting
northing
What is the
grid
reference
(GR) for the
ball in
which the
boy is about
to catch?
18
17
Answer:
GR238169
16
N
15
22
Northing
23
24
Eastings
25
26
27
Come up to the
Interactive White
Board
Compass Directions
68
F
H
I
B
66
21
22
E
NW
D
A
67 J
N
C
NE
W
G
23
E
SE
SW
S
24
What direction are you walking ?
A
C
G D
F
H
I J
B
E
A
Interactives
• http://mapzone.ordnancesurvey.co.uk/map
zone/PagesHomeworkHelp/maptivity/gridr
eferences/
• http://geographyfieldwork.com/TestGridIntr
o.htm
CLASS EXERCISE
Give the (AR) for
the following
features:
1. Church;
2. Village Hall;
3. Grove farm;
4. The dairy farm;
5. The town of Little
Plumpton;
6. The entire (AR)’s
for Gibbet Wood;
7. The (AR)’s that
Dale Road
passes through;
8. The approximate
(GR) of Grove
farm.
Interactives
• http://www.mape.org.uk/startower/maps/re
sources/map1.htm
• http://www.mape.org.uk/startower/maps/re
sources/map1b.htm