Maps and Data

Distribution maps of plants

BSBI distribution maps: based on up-to-date data from our live database.  The maps show occurrence records at up to 2km resolution. Some of the data are not fully curated, so the maps will include errors; please let us know about any mistakes.

NBN Gateway: distribution maps of all plants and animals at 10km resolution (or up to full details if you have access permission). The data are drawn from a number of sources, not just BSBI.

NBDC website: the equivalent of the NBN in Ireland. You don’t have to apply for permission to get full details of records.

New Atlas: a website developed in collaboration with the Biological Records Centre. It includes versions of the maps published in the last BSBI Atlas (based on data up to 2000). Data for these maps have been carefully checked.  The maps are a good choice if you need dependable (and largely error-free) information, but are not up-to-date. 

The BSBI Distribution Maps Scheme

Launched in 1950, the BSBI Maps Scheme is one of the world’s longest-running natural history distribution mapping projects. It is constantly updated and improved by the BSBI’s networks of volunteers, County Recorders and Referees, and it is always in use by scientists, conservationists and governmental bodies for determining the abundance, range and changes in the distribution of vascular plants and charophytes in Britain & Ireland. 

How it works

In the 1940s the Ordnance Survey plotted a grid across the whole of Britain based on km squares. There are some 3,000 10km x 10km squares in this grid, which are given codes such as SX45 or NO66 (S is for the southern 1000km square, N for the northern one), as shown on the map below.

For full details of the national grid, visit the Ordnance Survey web site.


Equivalent grid systems have since been created for Ireland and the Channel Isles.


Distribution maps

These are created by recording which species are found within each square of the national grid. The first Atlas was produced by the BSBI in 1962, showing black dots for records since 1930 and open circles for older records.

Since then there have been numerous similar maps published, most notably Scarce Plants in 1995, and the New Atlas in 2002. These plotted current records (‘black dots’) as those made after 1970 and 1987, respectively. Thus there are four traditional date classes for recording plants, as follows:

  • DC0 = -1929
  • DC1 = 1930-1969
  • DC2 = 1970-1986
  • DC3 = 1987-1999
  • DC4 = 2000-2009
  • DC5 = 2010-2019

Since 2000 we have been recording in decade-long date classes, so Date Class 6 will be 2020-2029. Another innovation is that we now produce hectad (10km x 10km) and tetrad (2km x 2km) scale distribution maps for all taxa. These maps are available to the public as well as to BSBI members.

Tetrad Maps

A tetrad is a 2km x 2km square, given a letter code as shown below. So tetrad SW41A is made up of the four 1km squares SW4010, SW4011, SW4110 and SW4111.


-- The DINTY system for tetrads -- 


For more about maps, and for support in using MapMate, go to our Resources page. 

The Distribution Database

The BSBI operates a Distribution Database (DDb) as a central store for all our records of plants and charophytes. It contains some 35 million biological records (April 2016) and is growing by approximately one million records every year. It is updated frequently from our network of Mapmate recorders and from other sources such as herbarium digitisation projects.


The database stores full details of the BSBI occurrence records and is regularly used by BSBI county recorders and taxon referees, who are responsible for curating the records and correcting mistakes.  Licensing and confidentiality constraints and the need to protect sensitive records mean that public access to the database is not available and because this is research-level, live data it is not appropriate for the general public or for consultancies.

Filtered, interpreted data can be obtained from local records centres, the NBN Gateway and other public sources.

Researchers, conservation workers and volunteers collaborating on BSBI projects may also be granted access, on a case-by-case basis. To discuss use of the database, please contact Kevin Walker.

Go to the BSBI Distribution Database (DDb).  

Taxonomy Database

Visit the BSBI’s taxonomy database, which gives plant names and their synonyms, chromosome numbers and details of much literature relating to British and Irish plants.

Go to the ‘Leicester’ Database

Vice counties

The system of counties and vice-counties was devised in the 1870s to create 113 units of roughly equal size covering the whole of Britain (the process was later repeated in Ireland). The boundaries of the vice counties do not change with political reorganisation so have remained the same ever since. Click on the link below for a handy web page showing the vice counties.

Vice county boundaries (Britain only).