نتایج جستجو برای: vegetation indices

تعداد نتایج: 127108  

Journal: Pollution 2015

To determine the suitable indices for vegetation cover and production assessment based on the remote sensing data, simultaneous digital data with field data belonging to the spring rangeland of the Semirom-Isfahan province were analyzed. During two years of monitoring the annual, grass, forb, and shrub vegetation cover and the total production data from 86 were collected. The Global Positioning...

Journal: :desert 2012
h. azarnivand m.a. zare chahouki h. joneidi

one of the characteristics in iranian model of desertification potential assessment (imdpa) is vegetation. sincevegetation is very important factor in the degradation of land, so some indices were determined for this item in order toevaluate desertification potential of arid, semi arid and arid sub humid areas of iran. the indices included vegetationcondition, exploit and revegetation. to calib...

2008
Zhengwei Yang Patrick Willis Rick Mueller

Multispectral satellite images have been utilized in the National Agricultural Statistics Service (NASS) for crop cover classification and crop acreage estimation since the 1970's. Though ancillary data is utilized to enhance the classification accuracy, there are few applications that maximize the utilization of the feature information of the given multispectral images. Every multispectral ima...

2007
Bunkei Matsushita Wei Yang Jin Chen Yuyichi Onda Guoyu Qiu

Vegetation indices play an important role in monitoring variations in vegetation.The Enhanced Vegetation Index (EVI) proposed by the MODIS Land Discipline Groupand the Normalized Difference Vegetation Index (NDVI) are both global-based vegetationindices aimed at providing consistent spatial and temporal information regarding globalvegetation. However, many environmental factors such as atmosphe...

Journal: :Remote Sensing 2017
Xiaochen Zou Matti Mottus

Leaf inclination angle distribution is an important canopy structure characteristic which directly impacts the fraction of the intercepted solar radiation. Together with the leaf area index (LAI) it determines the structure and fractional cover of a homogeneous crop canopy. Unfortunately, this key canopy parameter has usually been ignored when applying common multispectral vegetation indices to...

2000
Carlo Ricotta Giancarlo Avena Alessandra De Palma

Ž In the last two decades, numerous investigators have proposed cumulative vegetation indices i.e., functions which . encode the cumulative effect of NDVI maximum value composite time-series into a single variable for net primary Ž . productivity NPP mapping and monitoring on a regional to continental basis. In this paper, we investigate the relationships among three of the most commonly used c...

Journal: :Remote Sensing 2014
Weicheng Wu

A large number of vegetation indices have been developed and widely applied in terrestrial ecosystem research in the recent decades. However, a certain limitation was observed while applying these indices in research in dry areas due to their low sensitivity to low vegetation cover. In this context, the objectives of this study are to develop a new vegetation index, namely, the Generalized Diff...

2004
A. Bannari

Considering a forest cover (Balsam Fir with various densities) we analyze the sensitivity of several vegetation indices to ozone absorption using physical simulations in the spectral bands of MODIS, VEGETATION and AVHRR sensors. Except for the EVI, MSR and GARI, the results indicate that all the vegetation indices used in this study normalize the ozone absorption in particular TSARVI and GEMI. ...

Journal: :journal of rangeland science 0
mahtab safari shad phd student, department of natural resource, university of sari, iran. alireza ildoromi associate professor, dept of range& watershed management, malayer university iran. davoud akhzari davoud akhzari, department of watershed and rangeland management, malayer university, malayer 6571995863, iran. e-mail: [email protected], [email protected]

drought is a major problematic phenomenon mostly for semi-arid areas of iran. during drought periods, reduction in vegetation levels causes such problems as soil erosion, surface runoff, flood risk, etc. therefore, the assessment of drought effects on plant covers is the most important issue. this research was conducted in 2015 using the extracted vegetation indices from moderate resolution ima...

Journal: :desert 0
h. azarnivand associate professor, faculty of natural resources, university of tehran, karaj, iran m.a. zare chahouki associate professor, faculty of natural resources, university of tehran, karaj, iran h. joneidi assistant professort, university of kurdestan, sanandaj, iran

one of the characteristics in iranian model of desertification potential assessment (imdpa) is vegetation. sincevegetation is very important factor in the degradation of land, so some indices were determined for this item in order toevaluate desertification potential of arid, semi arid and arid sub humid areas of iran. the indices included vegetationcondition, exploit and revegetation. to calib...

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