What is WORLDMAP ?
WORLDMAP & GIS
The WORLDMAP project was begun in 1988 in response to the need for a platform on which to research and develop new analytical tools for biologists. It is based on the same database - analytical tools - map graphics model as many commercial geographic information systems (GISs). Yet unlike commercial GISs, rather than concentrating on database and graphics flexibility, WORLDMAP is designed to perform specialist biological analyses for unlimited numbers of species (or other area attributes) at maximum speed, in order to support truly inter-active exploration of biodiversity data for research. Many of the biological tools are not yet available from commercial GIS.
Where additional database and graphics flexibility is required, data and derived scores can be imported and exported in a growing range of formats. Nonetheless, a simple point-and-press map-based data editor is provided as part of the database module (below).
The grid approach
WORLDMAP is designed around analysing attributes of samples, usually sets of organisms. These sets are usually defined by the volume of space in which they occur, although for many studies the third dimension can be ignored, so that sets can be defined by an area of land or sea.
We follow a popular approach of dividing the surface area of the world into grid cells or polygons. For purposes other than choosing among land-management units for conservation, equal-area (ref 10) or nearly equal-area grid cells (ref 5) are often used because they reduce the species-area effects on diversity and rarity measures.
The samples are shown as grid cells that are usually arranged in a rectangular grid on the computer screen, which usually correspond to geographic volumes or areas. The attributes are usually lists of species or higher taxa. However, the area plots these grid cells represent do not have to be square in reality, or equal in area, or even regularly arranged.
The map of the world used for the original version of WORLDMAP is a cylindrical equal-area projection, orthomorphic at 46 degrees north and south of the equator. The effect is to divide the world by intervals of 10 degrees longitude and by calculated intervals of latitude to derive 864 cells of equal area (each approximately 611,000 square kilometres) in a grid of 36 columns by 24 rows.
Grids with larger numbers of cells, or cells of different sizes and shapes, are available by arrangement.
If you have any questions or problems please contact
WORLDMAP is written in C by Paul Williams. The ideas described here were developed through joint work with lab members and with Chris Margules, Bob Pressey, Tony Rebelo, Dan Faith, Melanie Kershaw and Paul Hopkinson (see publications). We are grateful to the Wissenschaftskolleg zu Berlin for Fellowships in support of this work, and to the NERC, Darwin Initiative and BBSRC for research grants. Mike Lowndes assisted in the compilation of these pages.