Digitizing as the main secondary spatial data production technique. Encoding vector points, lines, and polygons by tracing map sheets has diminished in importance, but remains a useful technique for incorporating historical geographies and local knowledge. "Heads-up" digitizing using digital imagery as a backdrop on-screen is a standard technique for editing and updating GIS databases. Tablet and on-screen digitizing, scanning and (semi)automatic vectorization.
Explain in which cases digitizing is a relevant data production technique
GI-N2K