The graphical method for a no-blocking radial staggered layout was introduced within the joint work between the Center For Solar Energy Studies (CSES), Tripoli, and Atlantis Energy Ltd, Bern. It locates the heliostats in the field of a solar central receiver plant so that they provide no blocking losses over the year. In this method the held is divided into certain groups to increase the efficient use of land. The method is a simple one when compared to cell-wise procedures, making it more suitable for preliminary design of heliostat fields. At the same time, the method can be represented by a set of mathematical equations, consequently facilitating its computer implementation In this paper a mathematical formulation of the method will be introduced, as well as its algorithm. Also, a criterion for the transfer to a new heliostat group is proposed based on mirror density. (C) 2000 Elsevier Science Ltd. All rights reserved.