نتایج جستجو برای: vegetation
تعداد نتایج: 47633 فیلتر نتایج به سال:
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...
[1] Degradation of cattle pastures is a management concern that influences future land use in Amazonia. However, ‘‘degradation’’ is poorly defined and has different meanings for ranchers, ecologists, and policy makers. Here we analyze pasture degradation using objective scalars of photosynthetic vegetation (PV), nonphotosynthetic vegetation (NPV), and exposed soil (S) derived from Landsat image...
A new instrument called a Multiband Vegetation Imager (MVI) (Kucharik et al., 1997), which uses a 16-bit charge-coupled device (CCD) camera and ®lter exchange mechanism to capture 2-band (visible and near-infrared) image pairs of plant canopies, has been used to measure the light distribution over sunlit leaves and indirectly infer leaf area index (LAI), sunlit LAI and leaf angle distribution (...
the purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. the study area is located in west of tehran province and southeast of hashtgerd, next to najm-abad village. after field studies, the index ...
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...
Studying MODIS Satellite Data Capability to Prepare Vegetation Canopy Map in Qazvin Plain Rangelands
Using satellite imagery is a reasonable option to overcome the field visits problems and limitations to evaluate the vegetation cover over the years. The present research has conducted to specify the percentage of vegetation cover of rangelands using Geographic Information System (GIS) and vegetation indices. The study area is located in Qazvin plain rangelands, Iran. In this study, the MODIS s...
Vegetation coverage has a significant influence on the land surface temperature (LST) distribution. In the field of urban heat islands (UHIs) based on remote sensing, vegetation indexes are widely used to estimate the LST-vegetation relationship. However, little evaluation work has been done on the comparison of the relationship between different vegetation indexes and LST. A Landsat Thematic M...
Determination of vegetation and soil interaction is necessary for sustainable use of rangeland ecosystem. Soil-vegetation interrelationships in galbanum (Ferula gummosa) habitats of Ataeeye and Shoorrud- Khorasan-e- Razavi Province, Iran were studied using multivariate analysis. The stratified- random system of sampling was employed to randomly collect vegetation and soil samples from 46 quadra...
Gully erosion is one of the most significant erosion types. This type of erosion is one of the most important sources of sediment in different regions of the world. Gullies often have different dimensions and complex characteristics and these characteristics may affect the distribution of vegetation. Topographic characteristics of gullies provide complex ecosystem for vegetation establishment. ...
For the analysis of vegetation areas using satellites, a variety of vegetation indexes such as NDVI and EVI have been developed. However, most indexes have weak response to grasping the type and quality (the growth state and situation) of vegetation. To grasp these vegetation characteristics, we have developed new vegetation indexes, i.e. shadow index (SI) and water stress trend (WST). We estim...
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