At present, in country archaeology, tape measure, steel tape measure, GPS, total station and other instruments are widely used to measure length, area and volume, and total station, GPS-RTK and other instruments are used to carry out topographic mapping, exploration layout and engineering lofting. So, what can hand-held laser rangefinder do? Handheld laser rangefinder can also measure interval, area, volume and lofting with cooperative theodolite.

Interval measurement is the most widely used function in archaeology. Here are two examples to illustrate: 1. In the process of making the plan and profile of the tomb, the length, width and height of the tomb should be measured and registered, and then made according to the scale. It is assumed that the tomb is a vertical pit tomb with the same size at the bottom. If the measured width of the burial chamber is to be measured, set the hand-held laser range finder (Hilti PD42) to start from the bottom of the instrument, then stick the bottom of the hand-held laser range finder to the tomb wall and keep the horizontal key, then the burial width data will be displayed on the screen. Length measurement is similar to width, depth measurement can be directly measured from the tomb entrance, and a target board is also placed at the tomb entrance so that the latter can be measured from the bottom of the tomb upwards, with the same effect. If the bottom of the tomb mouth is different, in order to avoid the influence of skewed tomb wall, the extension rod can be used to measure the time delay. 2. Measurement of sealed earth mounds. Set the hand-held laser rangefinder as a triangular measurement form, and then take the hand-held laser rangefinder as the pole (preferably horizontal to the bottom of the sealed mound) to measure the interval from the bottom to the top of the sealed mound. Then, the height of the sealed mound will be automatically calculated and displayed in the instrument. This function is especially useful in the wild. In the Great Wall resource survey, some beacon towers may be difficult to climb or approach, so the height of the beacon towers can be measured by this function. In the third national cultural relics survey, some ancient buildings and stone carvings are also difficult to approach and can be measured by this function.

Measurement of area and volume is also widely used in archaeology. For example, the exploration area, tomb opening area, city site area, exploration earthwork, tomb earthwork, etc. To accomplish these functions, you only need to switch the function options of the handheld laser rangefinder to the corresponding options, and then measure two or three data of the entity to obtain area and volume data. As for the lofting function of hand-held laser rangefinder, it will not be described in detail here, because the lofting function of total station and GPS-RTK is much stronger than it is.

Summary and Suggestions

Handheld laser rangefinder is quick, accurate, simple to operate and easy to carry. These advantages are worthy of our promotion in archaeological work. However, it also has some shortcomings, for example: the measuring range is near, usually about 200 meters, which cannot meet the requirements of large-scale measurement; The price is high, usually ranging from several hundred to several thousand yuan. Therefore, in archaeology, we should use hand-held laser rangefinder in cooperation with other surveying and mapping instruments to give full play to the advantages of various instruments and improve the accuracy and efficiency of archaeological surveying and mapping.