Geodesia et Descriptio Terrarum (Geodezja i Kartografia) 14 (3-4) 2015
AN OVERVIEW OF METHODS FOR TREE GEOMETRIC PARAMETER ESTIMATION FROM ALS DATA IN THE CONTEXT OF THEIR APPLICATION FOR AGRICULTURAL TREES
ALS, trees, agriculture, remote sensing
The aim of this paper is to overview and analyse existing methods for estimation of tree geometric parameters from Airborne Laser Scanning (ALS) data in the context of their possible application for agricultural areas. A detailed description of the estimation methodology proposed by various research groups is presented, including Canopy Height Model creation, tree identification, crown delineation in 2D and 3D, estimation of tree height, crown base height, crown diameters and crown volume. Efficiency and drawbacks of presented methods are identified. It is also analysed, whether the existing methods, originally developed for forestry areas, are suitable for agricultural trees.
Most of the natural and engineering objects undergo physical and chemical transformation processes which cause their cracking and displacement. Due to that there is a need for monitoring the use of proper control-measuring devices. In this paper, authors presented the concept of displacement measurements using a measuring system, consisting of a geodetic instrument coupled with a table micrometer and double signals target plate, fixed on the examined object. Test set can be used to monitor the relative displacements and strains: eg. blocks and monadnocks, in the corridors of the caves and in the mine galleries, galleries dams, locks or watergates, etc. The proposed concept of measurement methods and instrumentation, with a micrometric table and double signals target plate, can support already known (classical) as well as modern automated solutions.
COMPARISON OF DIGITAL TERRAIN MODELS OBTAINED FROM SMART STATION TECHNOLOGY
Marcin Uradziński, Adam Doskocz
Digital Terrain Model, GNSS, RTK, ASG-EUPOS, Smart Station
Creating Digital Terrain Model (DTM) is one of the most important goals, which are to be considered in Spatial Information Systems. Usefulness of satellite systems with combination of classical methods gives an opportunity of horizontal and vertical measurements. Nowadays, Digital Terrain Model becomes a standard geospatial product and is the main information layer used in Geographic Information Systems. This paper presents the processes of acquiring and updating data using GNSS satellite techniques, which enable easy and quick automatic measurements, as well as innovative technology to determine the position coordinates using the Leica Smart Station technology. The results of measurements of Total Station and RTK are also presented. Based on these measurements, the GRID DTM was created using Surfer 9 software and comparative analysis of the results were performed. It was found that the results obtained from satellite measurements are similar to tacheometric results. Data obtained from RTK GNSS measurements allowed to reproduce DTM. Comparing to the model developed from tacheometric data, for surface mesh created as GRID, it was found that an average height coordinate difference was of the order of 0.05 m.