Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: airborne and terrestrial laser scanning

Sortuj według:

Ogranicz wyniki do:

Wykorzystanie chmur punktów Lidar w ochronie czynnej borów chrobotkowych w Parku Narodowym "Bory Tucholskie"

Wężyk P., Hawryło P., Zięba-Kulawik K., Kuzera J., Turowska A., Bura M., Wietrzyk P., Kołodziejczyk J., Fałowska P., Węgrzyn M.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

2018

vol. 30

27--41

Zespół boru chrobotkowego (Cladonio-Pinetum) jest zbiorowiskiem wykształcającym się na suchych i ubogich w biogeny obszarach piaszczystych. Najlepiej zachowane płaty tego zbiorowiska roślinnego w Europie występują w Polsce północnej, w tym na terenie Parku Narodowego "Bory Tucholskie" (PNBT). Celem badań było określenie struktury przestrzennej wybranych drzewostanów sosnowych PNBT, w których zainicjowany został program ochronny czynnej borów chrobotkowych. Obszar badań obejmował część dwóch oddziałów leśnych PNBT z wydzieleniami: 18c, 19d, 19g, 19h, 19i, 19j i 19k. Badania przeprowadzono z wykorzystaniem lotniczego (ALS) i naziemnego (TLS) skanowania laserowego (LiDAR). Dzięki zastosowaniu technologii LiDAR możliwe było wykonanie bardzo precyzyjnego opisu struktury drzewostanów w przestrzeni 2D i 3D. W wyniku przeprowadzonych analiz określono szereg cech taksacyjnych i parametrów drzewostanów, takich jak: liczba i zagęszczenie drzew w drzewostanie, średnia odległość pomiędzy drzewami żywymi, liczba drzew martwych, pierśnicowe pole przekroju drzew żywych, zwarcie poziome koron, wskaźnik penetracji koron, wysokość górna drzew w wydzieleniu, wysokość podstawy korony drzewa, długość korony drzewa, objętość warstwy koron, powierzchnia 2D i 3D koron drzew, średni promień korony, współczynnik morfometryczny koron oraz zasięg pionowy martwych gałęzi. Opracowano także mapę występowania luk w wydzieleniach o powierzchni większej niż 2 m2. Badania rozpoczęte w 2017 roku są kontynuowane w 2018 roku z wykorzystaniem skanowania z platformy BSP (UAS) oraz TLS, które posłużą precyzyjnej ocenie zmian struktury przestrzennej drzewostanów, w których przeprowadzono cięcia prześwietleniowe.

Forest lichen communities develop on dry and poor in biogens sandy areas. The center of occurrence of this plant community in Europe coincides with Natura 2000 sites located in Poland, including the Bory Tucholskie National Park (BT NP). The aim of the study was to determine the spatial structure of selected Scots pine stands of BT NP, where a program of active protection of lichen communities was initiated. The research area included two forest compartments: 18 and 19. The analysis was performed in the following sub-compartments: 18c, 19d, 19g, 19h, 19i, 19j and 19 k. The research was carried out using airborne (ALS) and terrestrial (TLS) laser scanning (LiDAR). Thanks to the use of LiDAR technology, it was possible to make a very precise description of the structure of stands in 2D and 3D space. As a result of the conducted study, a number of stand parameters have been defined, such as: number of trees, tree density in the stand, number of live trees, average distance between living trees, number of dead trees, basal area, horizontal cover of tree crowns, crown penetration ratio, average height of trees, height of the crown base, tree crown length, crown layer volume, 2D and 3D crown surface, average crown radius, canopy relief ration and vertical range of dead branches. A map of crown gaps with an area of more than 2 m2 was also developed. Research activities with the use of laser scanning technology is continued in 2018 (repeated ALS and TLS scanning). The conducted research will allow to determine the influence of the stand structure on factors influencing the occurrence of lichens, including: shaping of microclimatic conditions.

Wprowadzenie do technologii skaningu laserowego w leśnictwie

Wężyk P.

Roczniki Geomatyki

2006

T. 4, z. 4

119-132

Precise information about current state and recent changes of forest stands is important for forest inventory and forest management, traditionally based on the sample plots method and human-made measurement of some geometry parameters of trees. To reduce the time-consumed and subjective methods, several techniques were developed based on GPS, photogrammetry, remote sensing and in the last years also the airborn and terrestrial laser scanning (lidar). This technology can be categorized according to different criteria, for instance according to the position of scaner in space we distinguish airborne laser scanning (ALS), satellite laser scanning (SLS) and terrestrial laser scanning (TLS). On the other hand, according to the type of method used for handling the laser light we distinguish scanners based on time-of flight "pulse ranging" or on continous wave ranging "cw"). The newest development of lidar offers full-waveform scanners capturing new information about the vertical structure of the vegetation layer (except the first and the last echo). Airborne laser scanning (ALS) is capable to generate small footprint diameters (10-30cm) allowing accurate determination of the height of a stand or even a single tree. Two main approaches to deriving forest information from lidar are: spatial distribution of canopy height and individual tree detection (recognition, segmentation, delineation). Depending on the number of laser pulses per sq meter (more than 3 or 4) and on the tree species and its age individual trees can be recognized. Based on the original point cloud, digital terrain model (DTM) and digital surface model (DSM) describing the treetops can be generated. Points for the interpolation of the DTM are selects with the use of special filtering algorithms. The canopy height model (CHM) is obtained by subtracting the DTM from the corresponding DSM. The DSM is calculated by means of the first pulse echo and the DTM with the last pulse echo. Satellite laser scanning (SLS) uses large laser footprints (25-70m) delivering such data as: canopy top heights, vertical distribution of intercepted surfaces (e.g. leaves and branches), ground surface topographic elevations. Good example of SLS are: Vegetation Canopy Lidar (VCL) consisting of a fivebeam instrument of 25 m contiguous along track resolution, with the beams spaced 2 km from one another on a distance of 8 km, or Geoscience.s Laser Altimeter System (GLAS) which has 3 lidar on board, acquires elevation profiles of the entire earth consisting of footprints 70 m in diameter spaced every 175m along the profile. Terrestrial laser scanning (TLS) is capable of collecting clouds (XYZ, intensity) of several million data points just in a few minutes. Applications making use of TLS in forest inventory and monitoring are focused on rapid semi-automatic recognition and determination of stand characteristics such as diameters on different heights, height, tree density, stem gap fraction in the canopy structure, defoliation and of course the position of the stem (XYZ). Integration of airborne and terrestrial laser scanning opens new dimension in the forest inventory applications delivering in short time huge data sets which can be semi- or full-automatically processed. Lidar technology additionally supported by optical source of data like digital aerial photos or VHR satellite images can easily broaden the application of this geoinformation technology in the forestry.