A method of pick correlation comprises the steps of displaying a pick marker on a display screen; directing the pick marker at an image on the display screen, the image comprising at least one line primitive, and the pick marker having a diamond shaped pick window corresponding thereto; subjecting the line primitive to a trivial test, the trivial test comprising enclosing the diamond shaped pick window in a least enclosing rectangle, wherein the diamond shaped pick window and the rectangle have a common center point, and rejecting the line primitive if the line primitive has both of its end-points outside of the same extended edge of the rectangle; if the line primitive cannot be trivially tested, subjecting the line primitive to a non-trivial test which does not require performing floating point operations, and accepting or rejecting the line primitive in accordance with the results of the non-trivial test; and considering accepted line primitives as being selected for further processing.