Eastings and Northings.
These are the grid lines that are marked on the map.
Eastings are the vertical lines on the map
Northings are the horizontal lines on the map.
To help identify individual squares and give grid references the grid lines are numbered.
Eastings: 00 to 99 going from West to East.
Northings: 00 to 99 going from South to North.
Hence the terminolgy Eastings and Northings.
These prefixes on the map can change on the map sheet that you are using for example Map sheet 69, 1,50,000 scale map of the Isle of Arran the prefix changes from NR to NS approx 2/3rds across the map so you have NR ending at 99 and the next grid square starting at NS 00.
When you qoute a six figure grid reference or any grid reference i,e, 4 , 6, 8 figures you should pur the two letters of the map you are using in front of the grid reference for example:
- You may have a grid reference of 509582 in SW Scotland. The grid reference you should qoute would be NX509582.
- Note: without the letters NX the grid reference 509582 would be repeated in every 100km square.
There is another way to qoute grid references for example.
- Sheet 55, Grid 903102.
- Or Sheet 55, Lochgilphead, Grid 903102.
Four Figure Grid Reference.
This method can be used to designate an area.
Or for exmaple you where going to meet someone. You can use the 4 figure. For example.
Meet me at the church in Grid square 7048 or meet me at the camp site in a specific grid square . But the rule for this is there must be only one church or campsite in that particular grid square.
The romer provides an easy and accurate way of giving and plotting grid references from and onto the map. The most popular scale of romers used are: 1:50,000, 1:25,000 and 1:40,000 map scales.
Grid references using the romer.
Place the corner of the romer on top of the location you wish to give a grid reference of, in this case it's the large boulder Ensure you are usung the correct scale of romer that corresponds to the map you are using.
locatin the Easting you require in this case 41 the count the amount of tenths from the boulder to the 41 Easting in this case its 4. So we have the first three digits of our grid reference 414
Next locate the Northing line for the square the boulder is in, rember its the horizontale line to South of the boulder which just happens to 21 again count the number of tenths from the boulder to the 21 Northung line which is 3. We know have the second 3 digits of the grid reference 213.
Put the two sets of numbers together reemember easting first and we have a the grid reference of the boulder which is 414213.
You must remember that a grid reference will place you inside a grid square. Point to remember here that this is not the exact position, ie, pinpointing it.
The longer the grid reference the smaller the square gets.
|GRID REFERENCE||GRID||AREA COVERED METRES|
|4 FIGURE||NS6052||1000 X1000|
|6 FIGURE||NS602525||100 X 100|
|8 FIGURE||NS60215256||10 10|
|10 FIGURE||NS6021452560||1 X 1|
The Silva Lightweight Compass comes equiped with three sets of romers, 1:50,000, 1:25,000 and 1:40.000.