R. S. Hooda

ASSESSMENT OF L-BAND SAR DATA AT DIFFERENT POLARIZATION COMBINATIONS FOR CROP AND OTHER LANDUSE CLASSIFICATION

In the present study evaluation of L-band SAR data at difierent polarization combinations in linear, circular as well as hybrid polarimetric imaging modes for crop and other landuse classiflcations has been carried out. Full-polarimetric radar data contains all the scattering information for any arbitrary polarization state, hence data of any combination of transmit and receive polarizations can be synthesized, mathematically from full-polarimetric data. Circular and various modes of hybrid polarimetric data (where the transmitter polarization is either circular or orientated at 45 - , called …=4 and the receivers are at horizontal and vertical polarizations with respect to the radar line of sight) were synthesized (simulated) from ALOS- PALSAR fullpolarimetric data of 14th December 2008 over central state farm central latitude and longitude 29 - 15 0 N/75 - 43 0 E and bounds for northwest corner is 29 - 24 0 N/75 - 37 0 E and southeast corner is 29 - 07 0 N/75 - 48 0 E in Hisar, Haryana (India) Supervised classiflcation was conducted for crops and few other landuse classes based on ground truth measurements using maximum-likelihood distance measures derived from the complex Wishart distribution of SAR data at various polarization combinations. It has been observed that linear full- polarimetric data showed maximum classiflcation accuracy (92%) followed by circular-full (89%) and circular-dual polarimetric data (87%), which was followed by hybrid polarimetric data (73{75%) and then linear dual polarimetric data (63{71%). Among the linear dual polarimetric data, co-polarization complex data showed better

Wetland Assessment and Monitoring Using Image Processing Techniques: A Case Study of Ranchi, India

Wetlands, the transitional zones that occupy an intermediate position between dry land and open water, regulate the flow of water and nutrients, thereby facilitating optimum functioning of the physical and biological cycles of nature. To conserve and manage wetland resources, it is important to invent and monitor wetlands and their adjacent uplands. Wetlands are most productive ecosystems besides being a rich repository of biodiversity and are known to play a significant role in carbon sequestration. Wetlands are halfway world between terrestrial and aquatic ecosystem and share properties of both. Wetlands exhibit enormous diversity according to their genesis, geographical location, water regime, chemistry, dominant plants and soil or sediment characteristic. Wetland vegetation provides a natural barrier to fast moving water and therefore aids in flood speed reduction. Remote sensing offers a cost effective means for identifying and monitoring wetlands over a large area and at different moments of time. The present paper describes the methodology and results of wetland area for the Ranchi city of the Jharkhand state for the year 1996-2004.The signatures of wetlands and associated land features are identified in unsupervised classification approach based on their DN value using Satellite data. There are drastic change in between 1996 and 2004. The spatial distributions of the NDVI values were evaluated to determine the cut-off points for the water bodies, and wetted area.

Analysis of Temporal Polarization Phase Difference for Major Crops in India

A polarimetric radar system measures the complete scattering matrix of a target in the backscattered fleld that includes magnitudes of linearly polarized scattering amplitudes and the co- polarised and cross-polarised phase angles. Apart from backscattering intensity, the co-polarization phase difierence (CPD) calculated from polarimetric synthetic aperture radar (SAR) data produces important information about target physical, geometrical and dielectric properties. In the present work, the distribution of CPD in C-band polarimetric SAR data corresponding to major kharif and rabi crops (denoting the monsoon and the winter season) and other land cover features have been studied over Central State Farm, Hisar, Haryana. The probability density functions (PDF) of CPD have been compared with dominant scattering contributions from these targets as obtained from polarimetric target decompositions. The results show that crops and other land cover features show characteristic CPD distributions, which relates well with crop physical and geometrical properties. An intuition of the rate of growth and plant vigour is indicative from the temporal PDF pattern.

Estimation of Wheat/Rice Residue Burning Areas in Major Districts of Haryana, India, Using Remote Sensing Data

Haryana has emerged as an important state for Rice & Wheat production in India contributing significantly in the central pool. Mechanized combine harvesting technologies, which have become common in Rice Wheat System (RWS) in India, leave behind large quantities of straw in the field for open burning of residue. Besides causing pollution, the burning kills the useful micro flora of the soil causing soil degradation. There is no field survey (Girdawari) data available with the Government for the areas where stubble burning is taking place. The present paper describes the methodology and results of wheat and rice residue burning areas for three districts of Haryana namely Kaithal, Kurukshetra and Karnal for the year 2010 using complete enumeration approach of multi-date IRS-P6 AWiFS and LISS-III data. In season ground truth was collected using hand held GPS and used to identify area of burnt wheat/rice residues, associated crops and land features. After geo-referencing the satellite images, district images were masked-out and multi-date image data stacks were created. Normalized Difference Vegetation Index (NDVI) of each date was generated and used at the time of classification along with other spectral bands. The non-agricultural classes in the image included: forest, wasteland, water bodies, urban/settlement and permanent vegetation etc. The vector of these non-agriculture classes were extracted from the land use, imported and mask was generated. During the classification non-agriculture area was excluded by using mask of these classes. From this the agricultural area could be separated out. The area was estimated by computing pixels under the classified image mask. In season multi-date AWiFS data along with available single-date LISS-III data between third week of April to last week of May are found to be useful for estimation of wheat residue burning areas estimation. The data between second week of October to last week of November is useful for estimation of rice residue burning areas estimation at district level.

Time series analysis of co-polarization phase difference PPD for winter field crops using polarimetric C-band SAR data

ABSTRACT The utility of time series polarimetric C-band data for vegetation state monitoring was explored to understand the mechanism of growth and phenology for important winter crops in India. Parameters investigated were HH–VV phase difference (co-polarization phase difference, PPD), amplitude ratio, and polarization indices. Data were acquired during the entire growth phase categorized as early, mid/peak vegetative, and post-vegetative /flowering phase. The trend emerging in this study showed a shift in the phase difference distribution for agricultural areas relating to the growth rate for various crops. The time series data set revealed that the PPD is a function of frequency and was directly affected by crop type (planophile or erectophile), vigour, structure, and crop biophysical parameters, particularly biomass. The behaviour of crop biomass with PPD responded differentially across crop architectures and vigour classes. Co-polarization index was found to be a good measure for discrimination in early growth stages while cross-polarization index suited in advanced vegetative stages where geometrical orientation was uniform. The PPD captured the change in frequency distribution resulting in a peaked distribution at sowing changing to smooth, well-spread frequency distribution as the peak vegetation stage approaches. This histogram nature is observed to be gradual for high-biomass crops and peaked in case of the low-biomass crops. It is indicative of the rate of growth; a low peaked normal curve indicates faster growth rate and resulting in high biomass. The amplitude ratio in the later phase of growth as on the third date is similarly altered as in the VV returns from the crop. Intuition of the rate of growth and plant vigour is obtained from the temporal PPD pattern. The current study shows that while phase differences and amplitude ratio carry little information content on a single resolution cell basis, their spatial distribution over a wider time span can be used to derive quantitative relationships between SAR response and crop condition. The synergy of information involving the above parameters were used to derive useful information on the vegetation.

Cropping System Analysis Using Geo-Informatics Approach: A Case Study of Panipat District, Haryana

A cropping system is defined as the cropping pattern and its management to derive benefits from a given resource base under a specific environmental condition. Crop rotation is a time-honored process of planting annual crops. The paper describes methodology and results of cropping system analysis for Panipat district of Haryana, climatologically characterized by hot summer, cold winter and dry air except during rainy season. Multi-date and Multi-season IRS LISS-III digital satellite data of 2007–2008 was geo-referenced with the already geo-referenced master image by collecting GCP’s using second polynomial order and Nearest Neighborhood (NN) resampling approach. District boundary was overplayed on the image and all the data elements (pixels) within this were extracted for further analysis. Multi-layer stacks were prepared for Kharif, Rabi and Summer seasons using multi-date images of each season. The stacked images of different seasons were classified using complete enumeration approach and unsupervised ISO-Data clustering classifier based on some defined conditions such as number of clusters, threshold, standard deviation etc. To improve the accuracy Normalized Difference Vegetation Index (NDVI) of each date and non-agricultural mask was generated and used during the classification. The Kharif, Rabi and Summer cropping pattern maps and statistics were generated using classified images and applying logical combinations. During Kharif season rice is the major crop which occupies 73,700 ha area and in the Rabi season wheat is major crop occupying 82,900 ha area. In the summer season most of the area is lying vacant as fallow and major crops are fodder, vegetables etc. Sugarcane is an annual crop and it is available in all three cropping seasons. Rice-Wheat-Other, and Rice-Wheat-Fallow and the major crop rotations identified in the district.