We devised an easy-to-use, small, and light field mapping instrument named‘ Handy Station’, composed of a compact laser range finder fixed on a revolving base on a tripod. This device is essentially of the same function as total stations, and enables us to measure horizontal distance, vertical distance, and horizontal direction of objects. Handy Station costs one third to one tenth of general total stations.
The compact laser range finder used for the device is Impulse 200 or TruPulse 200, with precisions of 0.01m and 0.1m for horizontal and vertical distance, respectively. We read horizontal direction toward targets by 0.1 degree on 1-degree marks plotted around the revolving tables. Thus, the accuracy of measurements by Handy Station is expected much less than that of total stations with millimeter and minute precision. Handy Station also does not accurately measure distance beyond 100 meters, while total stations accurately measure distance over 1 kilometer. However, for topographic mapping in fields, we seldom need such precision, but we need more maneuverability, especially when we use such instruments in a remote place where we have to carry them for distance. Handy Station is very compact and is about 2.5 kilograms for Impulse 200, and 1.5 kilograms for TruPulse 200, while total stations with tripod are bulky and weigh more than 10 kilograms. We can use an inexpensive reflector bought at a dollar shop for Handy Station.
Total stations automatically record readings that can be processed by a computer for drawing maps. On the other hand, we take notes for readings when we use Handy Station. It is recommendable to make notes and sketch maps around targets, in order to avoid misunderstanding about locations.
We compared performance of Handy Station with that of total stations by mapping a part of fault scarp along the Atera fault, central Japan. Time for mapping did not differ much among the instruments. Results were processed by Excel to get coordinates from horizontal distance and direction, and then contour lines were drawn by Surfer. As a result, it is indicated that the measurement by Handy Station can produce accurate maps that are precise enough for maps at a scale of one-to-several hundreds.