Comparison Between Topographic Surveys of Iron Caves: Case Study in the Brazilian Amazon

Abstract

The calculation of speleometric parameters (horizontal projection, height difference, area and volume) in the topographic mapping of caves is a requirement supported by law for the definition of the degree of relevance of cavities in Brazil. Thus, the objective of this work is to compare the conventional expeditious method (using compass, clinometer, tape measure and GNSS) with laser scanning technology regarding the topographic survey in a sample population of caves located in the Speleological Province of Serra dos Carajás, Pará, Brazil. Thus, the descriptive statistical analysis of the speleometric data obtained mathematically by the conventional topographic survey method of 1758 cavities was initially carried out to define the most relevant speleometric parameter from the point of view of cave framing as of maximum relevance. From this, the speleometric parameter volume surveyed by way of laser scanning was calculated and compared with the result obtained using the conventional method. Laser scanning brought greater speed and reduced exposure to risk in the field in data collection. In addition, the topographic survey with laser scanning is more accurate and in 80% of the results the value of the variable volume was lower than that obtained by means of the conventional survey.