For recording to provide effective data for local purposes, such as planning and conservation work or national analysis of how particular species are faring, records have to be related to sites.
Therefore, the grid reference for any butterfly record should be to at least 1km square accuracy (four-figure grid reference), and preferably six-figure references which pinpoint a sighting to a 100m x 100m square.
When it comes to mapping, butterfly records data are often plotted in a summary form on distribution maps e.g. as tetrads (2km squares) for local maps, or 10km squares for the national scale.
Generally atlas organisers seek to ensure that some recording is carried out within each tetrad or 10km square, to give a good level of mapping coverage.
| MultiMap Online Grid References |
If you do not own an OS map of the area which you need an OS grid reference for, you could try using MultiMap.
Just search for town or village nearest to your butterfly sighting and then zoom in to the actual location. Right click on the map and select 'place red circle here', then right click again to 'centre the map here'. Once you have done this, scroll down the page where MultiMap provides not only OS grid references but also local weather, postcode area and latitude and longitude data.
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| How to work out a grid reference |
Please use only the National Grid references from Ordnance Survey maps - not road maps, which may have non-standard grids.
1km squares are marked by a grid of light blue lines on 1:50,000 series (Landranger) OS maps. The grid reference of a 1km square consists of the 100km square code (e.g. SP), which will be marked somewhere on the map, followed by four numbers, which mark the bottom left-hand corner of the square (see example below).
Find out more about OS Landranger Maps on the OS web site
The first two numbers refer to the horizontal (East-West) scale and the second two the vertical (North-South). It is very important to put these in the right order.
A 6-figure (100m square) grid reference is derived by dividing the 1km square into tenths, from the left (west) and the bottom (south).
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For example, the map reference of the cross in the shaded square above is given by combining the east-west reference, 482, with the north-south reference, 937, giving a full reference of: SP482937.
When you move into another 1km square, record sightings there separately, so that important sites can be correctly identified.
If you do not have access to suitable maps or are not familiar with grid references, please do not be put off from recording the butterflies which you see. Contact your local coordinator and they may be able to help.
OS Landranger Maps which cover the Warwickshire, Coventry and Solihull area are numbers 139, 140, 141, 151, 152, |
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