Procedimentos de investigações e avaliações metodológicas no estudo morfológico de feições costeiras

Abstract

This study aimed to evaluate the methods and the equipment adopted in the morphological study of coastal features, in order to contribute useful information to the scientific community on the accuracy of data, listing the advantages, disadvantages and the types of care in topographic and geodetic survey. The methodology was divided into four stages: state of knowledge or art; office activities; laboratory activities and experimental activities. three experimental activities were carried out in two totally distinct areas for planimetric, altimetric and planialtimetric data through various methods and equipment. All altimetry data were reported to the average sea level from the Level Reference (RN) of the Brazilian Geography and Statistics Institute (IBGE) and the coordinates were obtained from the Real Time Kinematic (RTK) along with the seasons the Brazilian Continuous Monitoring Network in UTM coordinates and Geographic, the projection SIRGAS 2000 Spindle / Zone 24M. In planimetric survey the following methods were applied with their equipment: traversal by closed polygonal, absolute positioning with Global Positioning System (GPS) and relative positioning with RTK. The best method and apparatus was the relative RTK positioning, and second, it was traversal method polygonal closed with a total station. The difference in the position of the coordinates in the control point was 0,005 m horizontally both methods and equipment adopted. The use of the Global Positioning System (GPS) receiver and variables showed significant shifts horizontally. Thus, it should be rethought the use of equipment for scientific purposes in accordance with the purpose and scale of work. In altimetry survey the following methods were applied with their equipment: leveling with topographic level; Hydrostatic level with hose; trigonometric leveling with total station and relative positioning with RTK. Was I note both in experiment I and II in the experiment that the methods of leveling and hydrostatic showed better resultatos compared to other applied methods and equipment. It was found that the level of difference values, perimeter, area and volume near well, confirming the accuracy of both methods and equipment to obtain altimetric RTK despite having a high cost showed variations in altitudes centimeter accuracy. In planialtimetric survey a checkered mesh was established by applying the following methods with their equipment: leveling with topographic level; trigonometric leveling with total station and relative positioning with RTK. It was found that the leveling with topographic level showed better results than other methods and equipment. However, it was the most time consuming.