The use of hand-held laser rangefinders in archaeological research
At present, field archaeology in the extensive use of tape measure, steel tape measure, GPS, total station and other instruments for the length, area, volume and other measurements, the use of total station, GPS-RTK, etc. for terrain mapping, exploratory deployment, engineering sampling. So, what can the handheld laser rangefinder do? Handheld laser rangefinder can also achieve the measurement of distance, area, volume and with the latitude and longitude instrument for sampling and other functions.
Distance measurement, the most used function in archaeology. Here are two examples to illustrate:
1. The length, width and height of the burial should be measured and registered in the process of drawing the flat and profile of the burial, and then drawn according to the scale. Assume that the burial is a vertical cave mound tomb with the same large mouth and bottom. To measure the measured width of the burial chamber, set the handheld laser rangefinder (Hilti PD42) to count from the bottom of the instrument, then press the bottom of the handheld laser rangefinder against the wall of the tomb, keep the horizontal button, and then the data of the width of the burial will be displayed on the screen. Length measurement is similar to width, depth measurement can be measured directly from the mouth of the tomb down, also placed in the mouth of the tomb target plate, so that after the bottom of the tomb from the upward measurement, the effect is the same. If the bottom of the tomb is different, in order to prevent the effect of tilting the tomb wall, can be the use of extension rods, for delayed measurement.
2. Measurement of the sealed mound. The handheld laser rangefinder is set to triangulation mode, and then with the handheld laser rangefinder as the apex (* well with the bottom of the mound level), were measured to the bottom of the mound and the top of the distance, then, the height of the mound will be automatically solved and displayed in the instrument. This function is especially practical in the field, in the Great Wall resource survey some beacon platforms can not climb up or it is difficult to approach, you can use this function to measure the height of the beacon platform; in the third ** cultural relics census, some of the ancient buildings, stone carvings, etc. is also difficult to approach, you can also use this function to measure.
Area and volume measurement is also widely used in archaeology. For example, the area of the probe, the area of the burial opening, the area of the city site, the probe earth, the burial earth, etc.. To achieve these functions just need to handheld laser rangefinder function option switch to the corresponding option, and then measure the entity of two to three data can be obtained area and volume data. As for the sampling function of the handheld laser rangefinder, we will not do a detailed description here, because the total station and GPS-RTK sampling function is much more powerful than it.
Summary and Recommendations
The handheld laser rangefinder measures quickly, accurately, is simple to operate and easy to carry, and these advantages are well worth promoting in our archaeological work. However, it also has shortcomings, such as: measuring range is close, generally about 200 metres, can not meet the wide range of measurements; the price is high, generally ranging from several hundred to several thousand dollars. Therefore, in archaeology, we should handheld laser rangefinder and other mapping instruments with the use of a variety of instruments to give full play to the advantages of archaeological mapping, mapping accuracy and efficiency.
