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ŠUMARSKI LIST 11-12/2010 str. 54 <-- 54 --> PDF |
P. Kovácsová, M. Antalová: PRECISION FORESTRY – DEFINITION AND TECHNOLOGIES Šumarski list br. 11–12, CXXXIV (2010), 603-611 2. SCOPE OF RESEARCH – Problematika istraživanja The most important parts of precision forestry are new and modern technologies. Precision technologies are instrumentation, mechanization, and information technologies that measure, record, process analyze, manage, or actuate multi-source data of high spatial or temporal resolution to enable information based management practice or to support scientific discovery (Schmoldt, Thomson 2001). Precision forestry uses variety of tools and techniques, which can be differently categorised. Ziesak classifies techniques into seven main activity fields: – Surveying (terrestrial laser scanner, GPS, INS and digital surveying equipment), – Remote sensing (CIR, Airborn laser scanner), – Contact-free materials testing and measuring computer tomography (CT), ultrasound, video and laser scanner, – Monitoring - radio frequency identification (RFID) and electronic nose (aroma) technology, – Decision-making and harvest planning, – GIS, DSS and visualisation software, – Computer hardware. In this article tools are categorized into 5 categories. 2.1. Surveying technologies – Tehnologije izmjere Currently, photogrammetric measurement methods with support of terrestrial measurements using total stations, electronic tachymeter and fieldmaper are dominating in the forest mapping. However, these methods do not provide information on all the details hidden under crops, where there are various complications caused by considerable segmentation and opacity of terrain; that’s why geodetic (terrestrial) methods are used for supporting of photogrammetric measurement methods. Forest mapping technology GNSS – They are highly accurate satellite based radio navigation systems which provide us three dimensional positioning (elevation of the ground and coordinates x, y) and time information. This system gathers data position single objectives (Khali 2001). GNSS users have now fully available two satellite systems: NAVSTAR system developed by U.S.A and the Russian GLONASS system. The third satellite system GALILEO is the EU project, which aim is to build a new and an advanced satellite system, which would contribute to maximum efficiency in measurements of GNSS. The successful launch and expansion of the GALILEO system would be more than double the number of GNSS signals, which will be available to users (Tuček et al., 2007). Currently, in mapping both systems are used, which increases the accuracy and availability of mapping in extreme conditions (GLONASS system significantly offset the deficiency of American NAVSTAR satellites, which lead to increase of accuracy and availability of GNSS technology in extreme environments such as forest. The equipment on the GNSS basis, sometimes called GPS/GIS, is effective in data collection in forested areas, e.g. also in forest stand description (forest taxation), in forest detail object location and attribute collection in forestry thematic mapping (Tuček et al. 2002). These systems are used mainly for navigation on the ground and under canopy but LIDAR and IFSAR remote sensing technologies are equipped with GPS for obtaining accurate coordinate system of flying. At this time there is an effort to equip the new forest (wheeled skidder, track skidder) and agriculture technologies with GPS because of its navigation and monitoring abilities. GPS builds connections among map, image or digital database and real, physical location on the Earth surface. A possibility of usage of such equipment for tracing and navigation (from the map, plan or image to real conditions) is it’s another important attribute (Tuček, Suchomel 2003). Inertial navigation system – Inertial navigation system uses gyros, which is able to maintain on long- term indication of the specified direction. Measurement is based on the spread of the laser pulse in very long convoluted coils into fibreglass. With the progress of the motion sensor there are also emerging inertial navigation systems operating on different principles. These systems consist of sets capable of very sensitive accelerometers measurement changes in the direction of motion sensor. This sensor works in conjunction with a computer that continuously integrates the input signal of the accelerometers and determines the current location of the observed object. Inertial navigation is able to measure even in densely forested terrain, where other navigation may not work (Rapant 2002, Martinić et al. 2001). Terrestrial Laser scanner – Terrestrial laser scanning systems allows obtaining a large amount of data fast, called a point cloud. Point Cloud is a set of x, y, z coordinates and sometimes number of intensity, which after processing provides a 3D model of objects and terrain. Current researches are focused on forest inventory automation, for the derivation of forest stand and tree characteristics (height, diameter, round base, number of stem) and identification of the tree based on bark. |