Abstract: An improved method and apparatus for displaying visual indications of subsurface-derived earth measurements. Digital logging measurements are delivered to video circuits for graphic display. The video circuitry includes a cathode ray tube and digital processing circuitry whereby an image is continually scrolled along with depth reference lines in correlation with movement of the sonde through the borehole. A moving visible representation of a preselected portion of the measurement may thus be continuously observed as it is obtained, moving relative to the display to simulate sonde movement within the borehole. A digital memory technique reduces the number of digital co-ordinates required to be stored and time required for visual data and reference line generation and scrolling wherein digital representations of starting co-ordinates are sequentially incremented and displays made in functional response thereto.