Method and equipment for displaying drill holes and method for directing drill rod when holes are drilled into rock

A method and equipment for displaying holes to be drilled when drilling holes into rock with a rock-drilling rig having control equipment and a display belonging thereto and measuring means for defining the direction and position of a drill rod, by using a pre-designed drilling plan defined in a three-dimensional coordinate system, in which a starting point (19a to 21a) and end point (19b to 21b) is defined for each hole to be drilled. A base plane running through the end point (19b to 21b) of the hole and parallel to the projection plane is defined for each hole (19 to 21), and a projection of the intersection of a hole or its extension created when drilling in accordance with the current location of the drill rod and the defined base plane is displayed with a graphical location symbol on the projection plane.