The HAND model The HAND described by us in Nobre et al. (2011) led the international scientific community to appropriate the foundations of the model. As a result, there are different implementations of the HAND algorithm, almost all using GIS program scripts, such as Arc GIS and others. But all of these implementations, including our original IDL script that required the ENVI package to run, are difficult to use and offer limitations in processing and features, some requiring additional data input from the drainage network in order to calculate the HAND. Since 2012 we have been developing a versatile and robust standalone program, written in C++, with the ability to generate the normalized HAND topology directly from any digital topographic data. For applications in terrain mapping the program has the ability to classify the HAND topology, separating hydrologically homogeneous terrains. For applications in the predictive mapping of hydrological risk the program has the capacity to generate vector contours, normalized by drainage, indicating staged zones of flood risk. The program and manual can be downloaded free of charge, after registration. We initially developed the compiled version to run on Linux, which is stable. And we are also providing a compiled version for MAC OS that still needs tweaking, but which can be downloaded. We hope the program can be useful and we thank in advance feedback from users, reporting bugs, experiences and questions about usage and applications.The only requirement we make is that when reporting results of studies using the HAND Model, authorship credits be given to Nobre et al. (2011), or to Nobre et al. (2015) if the study dealt with natural disasters or to Cuartas et al (2012) if the study is about hydrological modeling. References Cuartas, L. A., Nobre, A. D., Hodnett, M. et al., 2012. Distributed hydrological modeling of a micro-scale rainforest watershed in Amazonia: Model evaluation and advances in calibration using the new HAND terrain model. Journal of Hydrology: 404, 13–29. Nobre, A.D., Cuartas, L.A., Momo, M.R., et al. 2015. HAND contour: a new proxy predictor of inundation extent. Hydrological Processes. DOI: 10.1002/hyp.10581 Nobre, A. D., Cuartas, L. A., Hodnett, M. et al 2011a. Height Above the Nearest Drainage – a hydrologically relevant new terrain model. Journal of Hydrology 404, 13–29. Nobre, A. D.; Silveira, A … Cuartas, L.A., 2011b. Aspectos físicos e geográficos das áreas ripárias no Brasil: análise preliminar da legislação. Ciência para o Código Florestal. São José dos Campos: Centro de Ciência para o Sistema Terrestre – INPE, 110 p. Relatório Cientifico.
