نتایج جستجو برای: landsat

تعداد نتایج: 9827  

Journal: :Remote Sensing 2014
Marian Vittek Andreas Brink Francois Donnay Dario Simonetti Baudouin Desclée

Monitoring land cover changes from the 1970s in West Africa is important for assessing the dynamics between land cover types and understanding the anthropogenic impact during this period. Given the lack of historical land cover maps over such a large area, Landsat data is a reliable and consistent source of information on land cover dynamics from the 1970s. This study examines land cover change...

2014
Reggie D. Walters Katelyn A. Watson Hans-Peter Marshall James P. McNamara Alejandro N. Flores

a r t i c l e i n f o Keywords: Fractional snow covered area Snow covered extent Downscaling Topography Hillslope scale Landsat NDSI Digital elevation models Snow remote sensing Watershed hydrology Accurate characterization of snow-covered area (SCA) and snow water equivalent (SWE) in complex terrain is needed to improve estimation of streamflow timing and volume, and is important for land surf...

2004
Hiroya Yamano Masayuki Tamura

Monitoring o f coral reef bleaching has hitherto been based on regional-scale, in situ data. Larger-scale trends, however, must be determined using satellite-based observations. Using both a radiative transfer simulation and an analysis o f multitemporal Landsat TM images, the ability o f satellite remote sensing to detect and monitor coral reef bleaching is examined. The radiative transfer sim...

Journal: :caspian journal of environmental sciences 2009
m. ajorlo h. ahmad husni mohd h. ridzwan abd

empirical models are important tools for relating field-measured biophysical variables to remotely sensed data. regression analysis has been a popular empirical method of linking these two types of data to estimate variables such as biomass, percent vegetation canopy cover, and bare soil. this study was conducted in a semi-arid rangeland ecosystem of qazvin province, iran. this paper presents t...

2003
C. D. Holifield S. McElroy

The water deficit index (WDI) derived from Landsat imagery was used to detect temporal and spatial changes in grassland transpiration. The WDI, which estimates relative evapotranspiration rates based on meteorological data and the relation between surface reflectance and temperature, has been successfully applied over heterogeneous terrain with little a priori information. In this study, WDI wa...

2008
Cao Guangzhen Hou Peng Jin Ya-Qiu

Using data fusion of multi-spectral and microwave radar images, a semiautomatic method is developed based on the level set method for application to urban road extraction. The fast marching method of level set makes data fusion. Radar remote sensing image can make up road breaks due to shadowing of high building or tree canopy in multi-spectral image, while multi-spectral image can be of helpfu...

2010
Hans Koren

This note is a review of works on retrieval of snow grain size from satellite images. A theoretical background is given and a number of models and algorithms are described. Most of the works are based on Landsat images with 30 m resolution and 7 optical channels, but the hyperspectral airborne AVIRIS sensor with 20 m resolution, and SAR has also been used. An algorithm derived from Landsat imag...

2006
Steven A. Sader

Landsat Enhanced Thematic Mapper Plus (ETM+) images were compared to Terra-MODIS imagery for detecting forest changes in northern Maine’s industrial forest. Advantages of MODIS imagery compared to medium spatial resolution imagery, like Landsat TM or ETM+, are its temporal frequency, its low data volume to cover large forest regions and, the data are free to download over the Internet. The obje...

2013
S. R. Xu C. C. Li N. K. Flint

A method for computer extraction of geological lineaments from LANDSAT images is presented. The variance thresholded map of each image is separated into eight gradient direction maps, where basic linear segments are determined each of which is based on the principal eigen vector of a cluster of pixels whose gradient direction is orthogonal to its orientation. A special linking algorithm operate...

2012
KristinaH. Yamamoto Sharolyn J. Anderson Rebecca L. Powell Donald G. Sullivan Paul C. Sutton

We introduce the use of remote sensing analysis in providing new insight in characterizing green turtle nesting habitat. A maximum likelihood classification (MLC) and a multiple endmember spectral mixture analysis (MESMA) were conducted on a Landsat image that contained six nesting beaches in Turkey that represent varying degrees of importance. Both techniques highlighted similarities of the ve...

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