**7. The future of survey data processing**

comes from the differing aims, but it also originates from the specialities of the surveillance techniques. Concerning the surveying part of the investigation, the position of the cave relative to the groundwater level is the most influencing factor followed by the passage geometry. The surveying can be extremely difficult in subaquatic caves, where the water is muddy and

During the last decade, the TLS surveying technology has evolved to a level of flexibility that makes it adaptable to suit different geometric conditions in caves [24]. There also exist several well-documented projects, which provide the necessary stepwise help in combining photo documentation with TLS survey data. The uniqueness of the geological settings and the hydrogeological history of the area however, is still an issue in interpreting the data. Thus, purely mathematical approaches extrapolating throughout whole regions must be handled with caution because they may lead to false results. It was shown by several authors that on regional scale, the regularities of the cave distribution in the karst depends on variables like the thickness and dipping of beds [25], presence/abundance of tectonic fractures [26], the rate and direction of vertical movements [27], and the hydrological settings (hypogenic/epigenic

GIScience in the context of cave investigations represents a convergence of surveying (geodesy), modeling (mathematics), and application of the results (different disciplines of sciences). The disciplines include mainly natural sciences (geology, hydrogeology, karstology, climatology, morphology, etc.), but archeology may also be involved if the cave contains cultural heritage. This highly varying scope of possible surveyors of caves brings up concerns about the reusability of the surveyed data. A spelunker should bear it in mind that the collected data will affect the cave in longer terms either positively or negatively. If the collected data is disclosed or unorganized, scientists of different disciplines may have to survey the cave over and over impacting the environment with each attempt. The importance of reworking the archives comes into front light especially in those cases when the cave environment has changed drastically (due to opening parts of it to public), but also in those cases when the environmental impact of a new

In a case study of the Buda Thermal Karst System (Hungary), Albert et al. [11] demonstrated how to use a GIS to obtain new scientific results from archive data. This project aimed to estimate the macro- and meso-scale conduit porosity within the limestone and marl sequence incorporating the cave. The archive documentation included survey records, maps, transversal, and longitudinal sections. A method was worked out to create 3D passage models from the survey database using Visual Basic scripts and a GIS capable mapping application (AutoCAD), and subsequently extract volumetric data from the models. The database has to be prepared prior to the modeling, and the scripts provided the automation for the process of making 3D shapes from database records. In this case, the data information system included the original survey records but without properly measured LRUD (left-right, up-down) data. The missing

easy in dry and comfortably wide passages with box-shaped transversal sections.

**6. Related sciences (convergence in scientific approaches)**

conditions [28]).

42 Cave Investigation

survey is high.

Technologies and methods that may be an integrated part of cave surveying in the future, have root in the present. The surveying techniques are changing fast, but the caves are still places where both the surveyor and the surveying instrument are challenged. The technological and ergonomic characteristics, the price and the handling of a new tool all should be optimal to reach a breakthrough and become widespread in cave surveying. As the DixtoX became popular a decade ago, and the TLS during the last decade, the emerging technologies like the LiDAR-based mobile mapping system [4], combined with close-range photogrammetry may take the place of the "most popular cave surveying" in the future.

Although, the mobile mapping systems are expensive and still unavailable for most cavers, technical requirements of close-range photogrammetry become affordable for wide public in the last decade. Even a mobile phone can be used to create a photorealistic 3D model of an irregularly shaped object, like a rock surface [33]. However, whole caves are not always suitable for photo documentation because of the casted shades of artificial lighting, contrasts and greatly varying distances. Archeological sites though are documented in several cases using the combined technology of TLS, a photogrammetry [19, 34]. From the aspects of Earth sciences, geophysical methods are also at hand to map the cavities and the lithology in the rock body that encloses a cave [35].

The seeds of the autonomous or semi-autonomous surveillance systems (robots and remotely controlled probes), which can combine the laser scanning technology along with other sensor types (magnetic, infra, sonar, gravimetric, etc.), are also present [36]. The tendency is toward the higher precision and the larger data size, and obviously the data management and the processing methods will also have to change to keep up with the higher demands. The increasing amount of data will demand for lager storage sizes if continuous recording is expected for hours, and the multiplication of sensors will demand for more power and space. Moreover, the system has to be ruggedized making it even larger. Contemporary fully autonomous systems—capable to navigate without GNSS (Global Navigation Satellite System)—are the size of a larger suite case and works only for a few hours. It is still a long time before these surveillance robots will autonomously do the caving instead of spelunkers. A rather probable option is the combination of semi-autonomous systems with the recent technologies. Using TLS for broad passages and drone swarms equipped with active sensors for high and tight passages will require human assistance, in positioning beacons for the swarm. Still these systems are in not even in planning phase at the moment.
