bct home

1Km Grid References

The 10km squares are divided again into 1km squares using the same type of grid. The reference for a 1km square is a four figure grid reference. In this example it is SN 6727. Put the eastings together (6 along for the 10km square and then 7 for the 1km square) then the northings.

NB: The 1km square is again divided by a grid into 100m squares. This gives the six figure grid reference usually used as a standard in biological recording.

When you locate the correct four figure grid reference for your 1km square on a 1:25000 scale map, you can clearly see the features of the square such as rivers, roads, field boundaries etc. The map will look something like the example shown.

It helps to check the square first for suitability. Because the sites are generated randomly, a square may sometimes include unsuitable areas such as unstable land or unsafe parts of town that are unmapped.

Your local knowledge will help you to rule these squares out. If you are unsure please ask, and if in any doubt about the safety of a square you can request another.

Select the square that you prefer from the list given to you, and write the grid reference you have chosen clearly on your survey form.



planning your survey
bat detectors
support surveying walks
surveying at spots
sign up
after your survey
sign up


The Bat Conservation Trust retains intellectual copyright of the material contained in this tutorial.
Any unauthorised use will be considered a breach of that copyright.