Integrating JERS-1 imaging radar and elevation models for mapping tropical rainforest communities in far North Queensland, Australia

The Wet Tropics World Heritage Area in Far North Queens- land, Australia consists predominantly of tropical rainforest and wet sclerophyll forest in areas of variable relief. Previous maps of vegetation communities in the area were produced by a labor-intensive combination of field survey and air-photo interpretation. Thus,. the aim of this work was to develop a new vegetation mapping method based on imaging radar that incorporates topographical corrections, which could be repeated frequently, and which would reduce the need for detailed field assessments and associated costs. The method employed G topographic correction and mapping procedure that was developed to enable vegetation structural classes to be mapped from satellite imaging radar. Eight JERS-1 scenes covering the Wet Tropics area for 1996 were acquired from NASDA under the auspices of the Global Rainforest Mapping Project. JERS scenes were geometrically corrected for topographic distortion using an 80 m DEM and a combination of polynomial warping and radar viewing geometry modeling. An image mosaic was created to cover the Wet Tropics region, and a new technique for image smoothing was applied to the JERS texture bonds and DEM before a Maximum Likelihood classification was applied to identify major land-cover and vegetation communities. Despite these efforts, dominant vegetation community classes could only be classified to low levels of accuracy (57.5 percent) which were partly explained by the significantly larger pixel size of the DEM in comparison to the JERS image (12.5 m). In addition, the spatial and floristic detail contained in the classes of the original validation maps were much finer than the JERS classification product was able to distinguish. In comparison to field and aerial photo-based approaches for mapping the vegetation of the Wet Tropics, appropriately corrected SAR data provides a more regional scale, all-weather mapping technique for broader vegetation classes. Further work is required to establish an appropriate combination of imaging radar with elevation data and other environmental surrogates to accurately map vegetation communities across the entire Wet Tropics.

Mapping the emergence of heart disease in a black, urban population in Africa: The Heart of Soweto Study

Background: There is increasing evidence that many populations in the developing world are in epidemiologic transition with the subsequent emergence of more affluent disease states. The Heart of Soweto Study will systematically investigate the emergence of heart disease (HD) in a large urban population in South Africa. Methods: Part of the conurbation of Johannesburg, South Africa, Soweto is a predominantly Black African community of I million individuals. During an initial two year period, all individuals presenting to the local Baragwanath Hospital (3500 beds) with any form of HD will be studied. Demographic and diagnostic coding data in those with pre-established HD will form an abbreviated clinical registry of > 12,000 prevalent cases. Similarly, socio-demographic, clinical and diagnostic data (e.g. echocardiography and ECG) in newly diagnosed patients will form a more detailed clinical registry of > 5000 incident cases. Sub-studies of the relationship between HIV status and H D and the optimal management of chronic heart failure will also be performed. Results: These data will provide a unique insight into the causes and consequences of a broad spectrum of HD-related conditions in a developing world community in epidemiologic transition. Initially documented Population rates, in addition to detailed examinations of the underlying risk factors and causes of HD-related morbidity/mortality will provide an important platform for future stages of the study: a community-based, population screening program and culturally specific primary and secondary programs of care. Conclusion: There is an urgent need to systematically track the emergence of HD in the developing world. Initially involving more than 15,000 individuals, the unique Heart of Soweto Study has the potential to provide a wealth of information in this regard. (c) 2006 Elsevier Ireland Ltd. All rights reserved.