نتایج جستجو برای: land cover vegetation

تعداد نتایج: 243729  

Journal: :desert 0
h.r. keshtkar msc. graduate, university of tehran, karaj, iran h. azarnivand professor, faculty of natural resources, university of tehran, karaj, iran h. arzani professor, faculty of natural resources, university of tehran, karaj, iran s.k. alavipanah professor, faculty of geography, university of tehran, tehran, iran f. mellati instructor, faculty of environment and natural resources, ferdowsi university, mashhad, iran

land cover is one of basic data layers in geographic information system for physical planning and environmentalmonitoring. digital image classification is generally performed to produce land cover maps from remote sensing data,particularly for large areas. in the present study the multispectral image from irs liss-iii image along with ancillary datasuch as vegetation indices, principal componen...

2003
R. K. Kaufmann L. Zhou R. B. Myneni C. J. Tucker D. Slayback N. V. Shabanov Jorge Pinzon

[1] We use statistical techniques to quantify the effect of interannual variations in vegetation within land covers on surface temperature in North America and Eurasia from satellite measures of surface greenness and ground based meteorological observations. During the winter, reductions in the extent of snow cover cause (in a statistical sense) temperature to rise. During the summer, increases...

1999

L and-use change in the United States represents an enormous uncontrolled experiment in the ways habitat changes influence plants and animals. When cities were built, land was plowed, or forests were cut, the effects on our native biota were not considered. Of course, humans have influenced the flora and fauna of North America over the ages. Native Americans established settlements, practiced a...

2008
Ge Sun Changqing Zuo Shiyu Liu Mingliang Liu Steven G. McNulty James M. Vose

Natural forests in southern China have been severely logged due to high human demand for timber, food, and fuels during the past century, but are recovering in the past decade. The objective of this study was to investigate how vegetation cover changes in composition and structure affected the water budgets of a 9.6-km Dakeng watershed located in a humid subtropical mountainous region in southe...

Journal: Desert 2007
A. Sood P. Sharma R. Mahey S. Bazgeer, S. Hundal

Abstract Decadal changes in land use/land cover for Balachaur watershed in Nawanshahar district, Punjab, India were studied using black and white aerial photographs for March 1984 on approximately 1:20,000 scale and multidate geocoded false colour composites (FCC) of IRS-1D LISS-III on 1:50,000 scale for March 2002, September 2002, and May 2003 and interpreted visually to prepare land use/land...

2016
Rubina Parveen Subhash Kulkarni V. D. Mytri S. Bharathi V. Shreyas R. Anirudh S. Sanketh P. D. Shenoy K. Venugopal

Extraction of vegetation is an important step for agricultural, forest and greenery mapping. The proposed method examines the complex process of land cover vegetation pattern classification using an IRS-1C LISS III image. Pre-processing was done by employing partial differential equation (PDE). Normalized differential vegetation index (NDVI) was applied to separate vegetation features from the ...

Journal: :Remote Sensing 2014
Linlin Lu Claudia Kuenzer Huadong Guo Qingting Li Tengfei Long Xinwu Li

Accurate mapping of land cover on a regional scale is useful for climate and environmental modeling. In this study, we present a novel land cover classification product based on spectral and phenological information for the Xinjiang Uygur Autonomous Region (XUAR) in China. The product is derived at a 500 m spatial resolution using an innovative approach employing moderate resolution imaging spe...

2013
Norman W. H. Mason Susan K. Wiser Sarah J. Richardson Michael J. Thorsen Robert J. Holdaway Stéphane Dray Fiona J. Thomson Fiona E. Carswell

An understanding of the processes governing natural afforestation over large spatial scales is vital for enhancing forest carbon sequestration. Models of tree species occurrence probability in non-forest vegetation could potentially identify the primary variables determining natural afforestation. However, inferring processes governing afforestation using tree species occurrence is potentially ...

2013
Catherine Bodart Andreas B Brink François Donnay Andrea Lupi Philippe Mayaux Frédéric Achard

AIM This study provides regional estimates of forest cover in dry African ecoregions and the changes in forest cover that occurred there between 1990 and 2000, using a systematic sample of medium-resolution satellite imagery which was processed consistently across the continent. LOCATION The study area corresponds to the dry forests and woodlands of Africa between the humid forests and the se...

Journal: :journal of rangeland science 2013
ali ariapour abolghasem dadrasi sabzevar sara toloee

land use may be regarded as one of the most important factors affecting theenvironment with respect to human activities. so far, destroying the rangelands andchanging them into the waste lands and poor rangelands has been proposed as the mostsignificant variations of land use done by human beings. this paper has been conducted toevaluate the variations of vegetation percentage and land uses in ...

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