Abstract: A method for recording compressed data which includes a perpendicular test as well as a parallel test for discarding handwritten data points relative to a series of guide lines. The parallel test determines whether a data point lies at a true distance within a predetermined threshold distance either side of the guide line. The perpendicular test determines whether the data point lies between two perpendicular lines through the end points of the guideline. Both tests must be satisfied before a data point is discarded. To save memory space, the guidelines are defined by an endpoint and a delta value. Error is maintained at a predetermined limit by adjusting the delta values prior to storage.