نتایج جستجو برای: Vegetation indices

تعداد نتایج: 127108  

Journal: :journal of rangeland science 2013
gholamreza zehtabian hossein azarnivand hasan ahmadi saeideh kalantari

one of the influential tools concerning the rangeland and vegetation sciences isthe technology of remote sensing and satellite data. satellite data have played essentialroles in preparing the needed information for studying the vegetation. vegetation has beenwidely recognized as one of the best indicators for determining the land conditions. usingvegetation indices is one of the techniques of r...

2009
Tayebeh Tabatabaie Fazel Amiri

SUMMARY Operational monitoring of vegetative cover by remote sensing currently involves the utilisation of vegetation indices. Vegetation indices are widely used for assessing and monitoring ecological variables such as vegetation cover, above-ground biomass and leaf area index. This study reviewed and evaluated different vegetation indices for estimating vegetation cover in rangelands in Cente...

2012
Farooq Ahmad

To enhance the vegetation signal in remotely sensed data and provide an approximate measure of live green vegetation, a number of spectral vegetation indices have been developed to estimate biophysical parameters of vegetation. The sensitivity of the normalized difference vegetation index (NDVI) to the soil background and atmospheric effects has generated an increasing interest in the developme...

Journal: :پژوهش های علوم و فناوری چوب و جنگل 0

identification of the best vegetation indices (vis) for use in quantitative analyzes of vegetation is one of the important issues for ecologists. the objective of this study was sensitivity evaluation of vegetation indices to a stand volume for identification of the best vegetation index (vi) in stand volume estimation using a statistical sensitivity method. also, another objective of this stud...

2003
Cem Ünsalan Kim L. Boyer

Vegetation indices have been used extensively to estimate the vegetation density from satellite and airborne images for many years. In this paper we first focus on one of the most popular vegetation indices, the normalized difference vegetation index (NDVI ) [1] and introduce a statistical framework to analyze it. We propose a solution to the saturation problem of this index based on our statis...

ژورنال: :مرتع و آبخیزداری 2012
فاضل امیری حسن یگانه

assessment process of vegetation cover by remote-sensing images should be based on understanding of the vegetation indices. vegetation indices are widely used for assessing and monitoring ecological variables such as vegetation cover, above-ground biomass and leaf area index. the aim of the present research was to study of the aster data capabilities to estimate the vegetation cover percentage ...

Journal: :pollution 2015
somayyeh jabbari seyed jamaledin khajedin reza jafari saeed soltani

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...

Gholamreza Zehtabian Hasan Ahmadi Hossein Azarnivand Saeideh Kalantari

One of the influential tools concerning the rangeland and vegetation sciences isthe technology of remote sensing and satellite data. Satellite data have played essentialroles in preparing the needed information for studying the vegetation. Vegetation has beenwidely recognized as one of the best indicators for determining the land conditions. Usingvegetation indices is one of the techniques of r...

2013
Fazel Amiri Abdul Rashid B. Mohamed Shariff

To determine suitable indices for vegetation cover and production assessment based on remote sensing data, simultaneous digital data with field data belonged to summer rangeland of southern part of Isfahan province were analyzed. During 2 years of monitoring, annuals, grasses, forbs and shrubs vegetation cover and total production data from sixty 1 square meter plots in each site were collected...

2003
j. Qi M. S. Moran F. Cabot

C u r r e n t vegetation indices are normally computed with directional spectral reflectances and are subjected to many external perturbations such as soil background variations, atmospheric conditions, geometric registration, and especially sensor viewing geometry. Subsequent use of these indices to estimate vegetation amounts would result in substantial uncertainties. To reduce the uncertaint...

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