Abdollah Seif; Tayyebeh Mahmoodi
Volume 23, Issue 89 , May 2014, , Pages 72-80
Abstract
During the last three decades, the process of producing topographic information has observed a development in data producing technology, from traditional and land mapping toward inactive methods of surface measurement and registration (like photogrammetry and remote sensing), and more recently toward ...
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During the last three decades, the process of producing topographic information has observed a development in data producing technology, from traditional and land mapping toward inactive methods of surface measurement and registration (like photogrammetry and remote sensing), and more recently toward active methods (like radar and Lidar). Lidar is a technique used to gather information from the surface which works by measuring distance with laser. Measurement in Lidar is based on this principle: with defined coordinates of the laser sending point, it is possible to measure coordinates of any point on the ground by measuring the oblique distance between pulse sending point and the ground surface and measuring the angle of wave sent between the pulse sending point and ground level. Images produced using Lidar data have a 472*697 pixel dimension. In fact, Lidar is a supplementary tool for collecting 3 dimensional information which aid spatial photogrammetry and remote sensing. The most important information received from this device is the distance between sensor and ground level which is measured by calculating the time period between pulse impact with earth surface and its return to the sensor. Moreover, the distance between ground surface and flying level of the airplane is repeatedly measured which determines ground surface and vegetation. Digital elevation model and digital surface model are products of Lidar. Features like plot parameters, average elevation of trees, surface of vegetation crown, elevation of the vegetation crown, diameter at breast height, single trees and jungle structure can be exploited by Lidar. The present article seeks to introduce Lidar and investigate its functions and applications.
Gholamhosein Rstegarnasab; Zahra Arzjani; Mansureh Banazadeh; Sara Bagheri
Volume 21, Issue 83 , November 2012, , Pages 82-85
Abstract
On the occasion of World astronomy day and the eighth student astronomy seminar, Mohammad ibn Zakariya Razi student research center in Shahr-e Ray launched an international project with the title of “Measuring Earth to Moon distance using non-Euclidean trigonometry” with the cooperation of ...
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On the occasion of World astronomy day and the eighth student astronomy seminar, Mohammad ibn Zakariya Razi student research center in Shahr-e Ray launched an international project with the title of “Measuring Earth to Moon distance using non-Euclidean trigonometry” with the cooperation of America, India, and Italy, Thailand. A large population of students in the participating countries took part in the project. Moreover, different national astronomy groups and societies cooperated. The present article seeks to provide practical astronomical and mathematical training on international level, so that students will be able to confirm figures and numbers discussed in scientific books and centers. In these measurements, students in Rey research center astronomy group took part in measuring the moon azimuth angle and its elevation in Picard region on its surface. The measurement results along with other tests performed by national and foreign groups showed an appropriate level of adaptability with pre-measured standard values.