In this paper, it is attempted to examine and compare different orientation, one recreational and another more precise, in the performance of two （global positioning system） receivers of forested areas. In doing thi...In this paper, it is attempted to examine and compare different orientation, one recreational and another more precise, in the performance of two （global positioning system） receivers of forested areas. In doing this, a field test on horizontal and vertical positional errors of GPS positioning at different points in the forested area of Taxiarchis-Vrastama University forest was conducted. The two GPS receivers were used to determine the positional accuracy of a selected number of points under tree canopies. Specifically, the precision and accuracy of Garmin＇s GPS positioning at different points were calculated and compared with the corresponding positioning and accuracy of another GPS system, namely the TOPCON GPS. By the calculation of various measures of accuracy and precision suitable for GPS receivers and the use of statistical methods, accuracy between the different receivers differed significantly is shown. Also, regression analysis revealed that the basal area and the number of available satellites are the most important factors for predicting position error.展开更多
Surveying and early detection of invasive weeds are essential for strategic management and monitoring. Accordingly, a weed mapping was conducted during July 2011, against native （Orobanche ramosa, Cuscuta spp., Sorgh...Surveying and early detection of invasive weeds are essential for strategic management and monitoring. Accordingly, a weed mapping was conducted during July 2011, against native （Orobanche ramosa, Cuscuta spp., Sorghum halepense and Xanthium strumarium） and non native （Abutilon theophrasti, Datura stramonium, Solanum elaeagnifolium and Verbesina encelioide） weeds of Lebanon. A global positioning system （Garmin 2006） was used for precise waypoint, elevation, navigation and distance. The result of interviewing and interacting with the residents in 95 villages distributed between the Beq＇aa and the North governorates of Lebanon, along with the observations made on the route, yielded the first detection of Abutilon theophrasti in both governorates. Solanum elaeagnifolium and Verbesina encelioide were not found in the agro-ecosystems of either governorates. This is the first report of the introduction ofAbutilon theophrasti in Lebanon and the establishment of a baseline data on weeds of Lebanon. The adoption of an integrated weed management program with a quarantine and control techniques and methods is needed to manage the spreading of weeds and to lessen their ability to adapt to a constantly changing system which uses several control practices.展开更多
文摘In this paper, it is attempted to examine and compare different orientation, one recreational and another more precise, in the performance of two （global positioning system） receivers of forested areas. In doing this, a field test on horizontal and vertical positional errors of GPS positioning at different points in the forested area of Taxiarchis-Vrastama University forest was conducted. The two GPS receivers were used to determine the positional accuracy of a selected number of points under tree canopies. Specifically, the precision and accuracy of Garmin＇s GPS positioning at different points were calculated and compared with the corresponding positioning and accuracy of another GPS system, namely the TOPCON GPS. By the calculation of various measures of accuracy and precision suitable for GPS receivers and the use of statistical methods, accuracy between the different receivers differed significantly is shown. Also, regression analysis revealed that the basal area and the number of available satellites are the most important factors for predicting position error.
文摘Surveying and early detection of invasive weeds are essential for strategic management and monitoring. Accordingly, a weed mapping was conducted during July 2011, against native （Orobanche ramosa, Cuscuta spp., Sorghum halepense and Xanthium strumarium） and non native （Abutilon theophrasti, Datura stramonium, Solanum elaeagnifolium and Verbesina encelioide） weeds of Lebanon. A global positioning system （Garmin 2006） was used for precise waypoint, elevation, navigation and distance. The result of interviewing and interacting with the residents in 95 villages distributed between the Beq＇aa and the North governorates of Lebanon, along with the observations made on the route, yielded the first detection of Abutilon theophrasti in both governorates. Solanum elaeagnifolium and Verbesina encelioide were not found in the agro-ecosystems of either governorates. This is the first report of the introduction ofAbutilon theophrasti in Lebanon and the establishment of a baseline data on weeds of Lebanon. The adoption of an integrated weed management program with a quarantine and control techniques and methods is needed to manage the spreading of weeds and to lessen their ability to adapt to a constantly changing system which uses several control practices.
