The distributions of British records are now often given using both the traditional Watsonian vice-county divisions and a government agency (Ordnance Survey) grid reference system (both are shown below). In MapMate you specify both in the record for a particular site.

British mapping systems: Watsonian vice-counties (left) and grid reference (right). These images are adapted from the Biological Records Centre online resources.

The grid reference squares are 100km² and represented by two letters. To describe smaller areas in these squares, successive figures are given after the letters, one for each axis. Each pair of figures refers to an area that is ten times smaller than the last, so two figures would refer to a 10km² area and six figures would refer to a 100m² area.

Six-figure grid references are the smallest generally acceptable area to have in a recording but are what I’m finding the most problematic and time consuming. After getting used to other online map services, such as Google Maps/Earth and the Flickr map, using our Ordnance Survey site is an irritating experience that makes me feel that they prefer you to buy paper maps: it only displays a 1km² grid, doesn’t always display the x and y axis coordinates, and has a small map (400×400 pixel) display which is sluggish to move around.

I am still thinking about what the easiest way work out six-figure grid references is. I think I may resort to paper maps with a transparent overlay. If anyone has got an easier way, please let me know! I want a system that will be usable for areas that greater than 1km², like country parks.