New possibilities for documenting historical underground spaces using handheld laser mobile scanners and modern visualization of acquired data

Abstract

Recently, there has been a significant increase in interest in historical mining sites as cultural monuments. For a long time, historical mining sites were neglected as cultural and technical monuments and were not accessible to the public. This article focuses primarily on the documentation, exploration, and accessibility of historical mining sites using modern geomatics technologies. The article deals with the historically rich mining activity in the Czech Republic, where there are several important areas of historical mining from the Middle Ages to modern times. Until recently, it was very difficult to accurately map completely irregular and poorly accessible underground spaces. The only methods that could be used were a miner’s compass, a tape measure, a folding ruler, or a laser rangefinder and inclinometer. With the rapid development of handheld laser mobile scanners using SLAM (simultaneous localization and mapping) technology, this task has become much easier; on a smaller scale, low-cost documentation technologies using smartphones, panoramic cameras, and appropriate applications can also be used. It is now possible to document hard-to-reach, dark, and, above all, very irregular and narrow spaces in high quality. Nevertheless, there are many problems that the article points out and analyzes; these include measurement speed, cost, accuracy, and the effects of humidity and lighting. The SLAM method of handheld mobile laser scanners proves to be the most powerful.