Grid References
The vertical and horizontal lines which divide the map into small squares are called Gridlines
The
vertical lines running from bottom to top and increasing eastwards are known as
Eastings.
The
horizontal lines running from left to right
and increasing northwards are called Northings
Grid
references are stated in six figures. Eastings are stated first followed by
Northings. The length between two grid lines are always sub-divided into units ten to give a third digit but the
decimal points are eliminated. See the diagram below:
The position of any place on a map is given by the point at which two lines at right angles to one another meet. For example the value of A on the above diagram can be as follows:
Give 2
digit number of the easting immediately to the left of point A.
Imagine
that the space between the two easting gridlines is divided into ten units.
This would give you the estimate of the 3rd digit of point A.
Give
the two digit number of the northing immediately below point A.
Estimate
how many tenth point is above the line of Northing.
Combine
the figures for easting and northing to
get a Six figure grid reference of point
A which is Easting 70.0, Northing 10.0
The GR for Point A is 700100
,
Boreholes, road junctions among others, the 3rd digit of the easting and northing should
be taken from the central point of
any of those features mentioned.
Study Activity
In
your exercise books, try to get the grid references for points B, C & D.