An Approach to Develop Interpretation Keys for the Analysis of Single Band Bhaskara Satellite TV-Data

Bhaskara, the first Indian Earth Observations Satellite was launched on June 7, 1979. The two primary payloads onboard the Bhaskara satellite were two Television cameras (TV Camera) and two frequency Satellite Microwave Radiometers (SAMIR). The salient features of the TV camera and SAMIR payloads are summarised and given in Table 1. Since the Bhaskara TV data is having a low resolution and as the data was acquired in only one band, namely, 0.54-0. 66 µm, the utility of the data from the point of view of information extraction on earth resources is limited. Moreover, because of its orbital characteristics the data is acquired at different times of the day and thus under various illumination conditions. This note discusses an approach that is designed to increase the scope of utilisation of this data. This approach is developed using both digital and photographic techniques with a view to arrive at a standard set of keys for analysing and interpreting the TV data. The basis of the digital technique is the frequency distribution of gray tones (reflectance values) for identifying major cover types, classifying them and generation of three new data sets by assigning pseudo grey codes to the classified data. The pseudo gray coded data is then used to generate photographically colour codes for each of the cover type. Each pseudo data set is turned into a photographic film transparency and is assigned the colours red, green and blue respectively. The colour composite made using these transparencies is the new colour coded thematic ground cover picture from Bhaskara

An exact trend test for correlated binary data

The problem of testing a dose-response relationship in the presence of exchangeably correlated binary data has been addressed using a variety of models. Most commonly used approaches are derived from likelihood or generalized estimating equations and rely on large-sample theory to justify their inferences. However, while earlier work has determined that these methods may perform poorly for small or sparse samples, there are few alternatives available to those faced with such data. We propose an exact trend test for exchangeably correlated binary data when groups of correlated observations are ordered. This exact approach is based on an exponential model derived by Molenberghs and Ryan (1999) and Ryan and Molenberghs (1999) and provides natural analogues to Fisher's exact test and the binomial trend test when the data are correlated. We use a graphical method with which one can efficiently compute the exact tail distribution and apply the test to two examples