Journal of the Indian Society of Remote Sensing, 2004
Parametric kernel-based models for Bi-directional Reflectance Distribution Function (BRDF) of veg... more Parametric kernel-based models for Bi-directional Reflectance Distribution Function (BRDF) of vegetated land surfaces attempt to describe the BRDF as a linear superposition of a set of kernels describing basic angular shapes. The kernels and associated model coefficients are derived as approximations to the underlying theories of radiative transfer as well as geometric-optical scattering within vegetation canopies. In the present study,
Journal of the Indian Society of Remote Sensing, 2005
This paper reports a study on multi-temporal polarized response of wheat crop from spaceborne ADE... more This paper reports a study on multi-temporal polarized response of wheat crop from spaceborne ADEOS-POLDER sensor over a homogeneous wheat region of Punjab, India. Both the polarized as well as total reflectance of wheat were observed at different scattering angles for two spectral bands i.e. 670 nm and 865 nm during crop growth from November to April in rabi 1996-97 season. Results show that sun-target-viewing geometry plays an important role in polarization property. The top of atmosphere (TOA) polarized reflectance is found to decrease exponentially with increasing scattering angle. Polarized reflectance of crop was found to be an order of magnitude smaller in comparison to the total reflectance. An attempt was also made to model the observed polarized behavior over an agricultural area using a theoretical simplified crop reflectance model and accounting for atmospheric molecular (Rayleigh) contribution in the single scattering approximation. It was found that there was a decrease in the polarized reflectance at the grain filling (heading) stage of wheat crop. This is in accordance with ground-based observations and can be due to the reduction in the specular component of the reflected light during post-heading stage of the crop.
A study has been carried out to assess angular variations in red and near infrared (NIR) reflecta... more A study has been carried out to assess angular variations in red and near infrared (NIR) reflectance of different features of the Earth's surface in a common overlap area of accumulated four-date Indian Remote Sensing Satellite (IRS-1D) Wide Field Sensor (WiFS) data from the first fortnight of October 2003. An improved dark object subtraction (DOS) method has been used to
IEEE Transactions on Geoscience and Remote Sensing, 2001
The variations of NDVI for crops, semi-evergreen forest, dry deciduous forest, and sand have been... more The variations of NDVI for crops, semi-evergreen forest, dry deciduous forest, and sand have been analyzed as a function of date of acquisition at 670 and 865 am using ADEOS-Polarization and Directionality of Earth Resources (POLDER) data acquired over India. After correcting the data for atmospheric effects, a semi-empirical bidirectional reflectance distribution function (BRDF) model has been fitted to the data to extract angularly normalized target reflectances. It is shown that atmospheric corrections and angular normalization are important in the quantitative analysis of NDVI and its temporal variations
Abstract Land use is described as a piece of land that is put to various uses by human beings, wh... more Abstract Land use is described as a piece of land that is put to various uses by human beings, whereas the natural cover of the land is the land cover. The land use pattern of an area or region keeps on changing with time as a result of interactions between many factors i.e. drivers and the land.. Technically, land use and land cover change means quantitative changes in the areal extent (increase or decrease) of a given type of land use and land cover respectively. Land use and land cover change is a manifestation of both anthropogenic and environmental – climate driven, factors. The climatic drivers could be – changing precipitation, change in temperature or pressure. Another most important driver is the socio-economic factors like, total population, number of household, sex ratio, SC/ST population etc. The third important driver is the terrain or the topography like terrain undulations, varying slopes and aspects etc. Other important drivers could be infrastructure changes, changi...
Reliable interpretation of earth surface characteristics from remote sensing imagery depends larg... more Reliable interpretation of earth surface characteristics from remote sensing imagery depends largely on the positional accuracy of the ground control points (GCP), used to generate cartographically accurate and quality image data products. Datum, projection and units of the GCPs used in the rectification of the satellite imagery, becomes very important when one wants to compare and validate the derived information
Agriculture and Hydrology Applications of Remote Sensing, 2006
Hydrological parameters have vital role in civil engineering, infrastructure planning and natural... more Hydrological parameters have vital role in civil engineering, infrastructure planning and natural resource management. Since the last one and a half-decade their extraction using the High-resolution satellite stereo data has been very helping and less time consuming. In the earlier times, the ground surveys use to take a lot of time to cover a small area. Whereas with the availability of high accuracy Digital Elevation models from satellite stereo data one can extract these parameters with ease and good accuracy. During last one and half-decade vast experience has been gained in techniques of processing stereo data acquired from space. This paper deals with the extraction and validation of hydrological parameters from digital elevation model (DEM) derived using CARTOSAT-1 stereo data. In this paper two sub-watershed, one in Chamoli, Uttaranchal and other in Shimla, Himachal Pradesh were selected, A detailed morphometric analysis of the derived drainage network from the various sources and using various algorithms has been carried out. The parameters like stream order, stream length, bifurcation ratio, length ratio etc., have been used for comparison purpose.
Journal of the Indian Society of Remote Sensing, 2003
... 24 Anuj Mahtab et al. Fig. 6. Drainage pattern extracted from ARC/INFO DEM Fig. 7. Contours f... more ... 24 Anuj Mahtab et al. Fig. 6. Drainage pattern extracted from ARC/INFO DEM Fig. 7. Contours from topographical map (1:50, 000 scale) They are thankful to Sri R.Ramachandran, Sri ASRKV Murali Mohan, Ms. A. Bhaskar and Sri Pramod of ADRIN, Secunderabad for their help ...
Journal of the Indian Society of Remote Sensing, 2007
CARTOSAT-1 satellite, launched in May, 2005 is a dedicated along track stereo mission providing h... more CARTOSAT-1 satellite, launched in May, 2005 is a dedicated along track stereo mission providing high quality data for topographic and cartographic applications. The present paper describes the evaluation of the Cartosat-1 stereo data, mainly through the generation and validation of DEM for moderately undulating and hilly areas. Photogrammetric techniques have been used for generation of DEM and Orthoimage for two cases i.e. 1) using RPCs (Rational Polynomial Coefficients) and 2) using RPCs along with ground control points. Root Mean Square Error (RMSE) in elevation values for the moderately undulating (Dehradun) and hilly area (Shimla), are found to be 4.38 and 3.69m respectively.
With the availability of high spatial resolution stereo images it has become very easy to generat... more With the availability of high spatial resolution stereo images it has become very easy to generate Digital Elevation Model (DEM) of any type of terrain. This type of imaging has not only saved time involved in actual surveying but has also provided new opportunities in extracting terrain parameters like drainage, watershed boundary, slope, aspect etc. in shortest possible time. In Hilly terrains, DEM is used to correct the satellite images for the tilt and relief displacement effects. The photograph thus corrected is known as an Orthoimage and the correction procedure as orthorectification. The stereo images in hilly terrain contain distortions due to the viewing geometry. The distortions in the images are due to 1) Relief or terrain height and 2) very high slopes. Relief distortion is irrespective of the slope magnitude as well as aspect and can be corrected through the process of orthorectification. The second type i.e. distortion due to high slopes, is not taken care by the ortho...
Journal of the Indian Society of Remote Sensing, 2004
Parametric kernel-based models for Bi-directional Reflectance Distribution Function (BRDF) of veg... more Parametric kernel-based models for Bi-directional Reflectance Distribution Function (BRDF) of vegetated land surfaces attempt to describe the BRDF as a linear superposition of a set of kernels describing basic angular shapes. The kernels and associated model coefficients are derived as approximations to the underlying theories of radiative transfer as well as geometric-optical scattering within vegetation canopies. In the present study,
Journal of the Indian Society of Remote Sensing, 2005
This paper reports a study on multi-temporal polarized response of wheat crop from spaceborne ADE... more This paper reports a study on multi-temporal polarized response of wheat crop from spaceborne ADEOS-POLDER sensor over a homogeneous wheat region of Punjab, India. Both the polarized as well as total reflectance of wheat were observed at different scattering angles for two spectral bands i.e. 670 nm and 865 nm during crop growth from November to April in rabi 1996-97 season. Results show that sun-target-viewing geometry plays an important role in polarization property. The top of atmosphere (TOA) polarized reflectance is found to decrease exponentially with increasing scattering angle. Polarized reflectance of crop was found to be an order of magnitude smaller in comparison to the total reflectance. An attempt was also made to model the observed polarized behavior over an agricultural area using a theoretical simplified crop reflectance model and accounting for atmospheric molecular (Rayleigh) contribution in the single scattering approximation. It was found that there was a decrease in the polarized reflectance at the grain filling (heading) stage of wheat crop. This is in accordance with ground-based observations and can be due to the reduction in the specular component of the reflected light during post-heading stage of the crop.
A study has been carried out to assess angular variations in red and near infrared (NIR) reflecta... more A study has been carried out to assess angular variations in red and near infrared (NIR) reflectance of different features of the Earth's surface in a common overlap area of accumulated four-date Indian Remote Sensing Satellite (IRS-1D) Wide Field Sensor (WiFS) data from the first fortnight of October 2003. An improved dark object subtraction (DOS) method has been used to
IEEE Transactions on Geoscience and Remote Sensing, 2001
The variations of NDVI for crops, semi-evergreen forest, dry deciduous forest, and sand have been... more The variations of NDVI for crops, semi-evergreen forest, dry deciduous forest, and sand have been analyzed as a function of date of acquisition at 670 and 865 am using ADEOS-Polarization and Directionality of Earth Resources (POLDER) data acquired over India. After correcting the data for atmospheric effects, a semi-empirical bidirectional reflectance distribution function (BRDF) model has been fitted to the data to extract angularly normalized target reflectances. It is shown that atmospheric corrections and angular normalization are important in the quantitative analysis of NDVI and its temporal variations
Abstract Land use is described as a piece of land that is put to various uses by human beings, wh... more Abstract Land use is described as a piece of land that is put to various uses by human beings, whereas the natural cover of the land is the land cover. The land use pattern of an area or region keeps on changing with time as a result of interactions between many factors i.e. drivers and the land.. Technically, land use and land cover change means quantitative changes in the areal extent (increase or decrease) of a given type of land use and land cover respectively. Land use and land cover change is a manifestation of both anthropogenic and environmental – climate driven, factors. The climatic drivers could be – changing precipitation, change in temperature or pressure. Another most important driver is the socio-economic factors like, total population, number of household, sex ratio, SC/ST population etc. The third important driver is the terrain or the topography like terrain undulations, varying slopes and aspects etc. Other important drivers could be infrastructure changes, changi...
Reliable interpretation of earth surface characteristics from remote sensing imagery depends larg... more Reliable interpretation of earth surface characteristics from remote sensing imagery depends largely on the positional accuracy of the ground control points (GCP), used to generate cartographically accurate and quality image data products. Datum, projection and units of the GCPs used in the rectification of the satellite imagery, becomes very important when one wants to compare and validate the derived information
Agriculture and Hydrology Applications of Remote Sensing, 2006
Hydrological parameters have vital role in civil engineering, infrastructure planning and natural... more Hydrological parameters have vital role in civil engineering, infrastructure planning and natural resource management. Since the last one and a half-decade their extraction using the High-resolution satellite stereo data has been very helping and less time consuming. In the earlier times, the ground surveys use to take a lot of time to cover a small area. Whereas with the availability of high accuracy Digital Elevation models from satellite stereo data one can extract these parameters with ease and good accuracy. During last one and half-decade vast experience has been gained in techniques of processing stereo data acquired from space. This paper deals with the extraction and validation of hydrological parameters from digital elevation model (DEM) derived using CARTOSAT-1 stereo data. In this paper two sub-watershed, one in Chamoli, Uttaranchal and other in Shimla, Himachal Pradesh were selected, A detailed morphometric analysis of the derived drainage network from the various sources and using various algorithms has been carried out. The parameters like stream order, stream length, bifurcation ratio, length ratio etc., have been used for comparison purpose.
Journal of the Indian Society of Remote Sensing, 2003
... 24 Anuj Mahtab et al. Fig. 6. Drainage pattern extracted from ARC/INFO DEM Fig. 7. Contours f... more ... 24 Anuj Mahtab et al. Fig. 6. Drainage pattern extracted from ARC/INFO DEM Fig. 7. Contours from topographical map (1:50, 000 scale) They are thankful to Sri R.Ramachandran, Sri ASRKV Murali Mohan, Ms. A. Bhaskar and Sri Pramod of ADRIN, Secunderabad for their help ...
Journal of the Indian Society of Remote Sensing, 2007
CARTOSAT-1 satellite, launched in May, 2005 is a dedicated along track stereo mission providing h... more CARTOSAT-1 satellite, launched in May, 2005 is a dedicated along track stereo mission providing high quality data for topographic and cartographic applications. The present paper describes the evaluation of the Cartosat-1 stereo data, mainly through the generation and validation of DEM for moderately undulating and hilly areas. Photogrammetric techniques have been used for generation of DEM and Orthoimage for two cases i.e. 1) using RPCs (Rational Polynomial Coefficients) and 2) using RPCs along with ground control points. Root Mean Square Error (RMSE) in elevation values for the moderately undulating (Dehradun) and hilly area (Shimla), are found to be 4.38 and 3.69m respectively.
With the availability of high spatial resolution stereo images it has become very easy to generat... more With the availability of high spatial resolution stereo images it has become very easy to generate Digital Elevation Model (DEM) of any type of terrain. This type of imaging has not only saved time involved in actual surveying but has also provided new opportunities in extracting terrain parameters like drainage, watershed boundary, slope, aspect etc. in shortest possible time. In Hilly terrains, DEM is used to correct the satellite images for the tilt and relief displacement effects. The photograph thus corrected is known as an Orthoimage and the correction procedure as orthorectification. The stereo images in hilly terrain contain distortions due to the viewing geometry. The distortions in the images are due to 1) Relief or terrain height and 2) very high slopes. Relief distortion is irrespective of the slope magnitude as well as aspect and can be corrected through the process of orthorectification. The second type i.e. distortion due to high slopes, is not taken care by the ortho...
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