A blasting system facilitates the actuation of a plurality of programmable detonators according to a desired blasting pattern, to cause the discharge of a plurality of associated charges, by downloading to the detonators blasting information that can be automatically determined by a portable handheld unit that incorporates a positional detecting device, such as a GPS device. The blasting information for any given detonator can be determined by the handheld unit as a function of the distance and the direction of the movement of the unit to the detonator, and/or by the actual GPS location while at the site of the detonator. This automatic determination of blasting information, and particularly the delay times, based on the movement of the unit to the detonator, eliminates error prone human calculations of the delay times needed for multiple detonators at a blasting site. This simplifies the operations and procedures needed for achieving a desired blasting pattern, without sacrificing safety or quality.