System Science and Informatics Unit

Short Biography

B. S. Daya Sagar is a Professor (Higher Administrative Grade) of the Systems Science and Informatics Unit (SSIU) at the Indian Statistical Institute. Sagar received the M.Sc and Ph.D degrees from the Faculty of Engineering, Andhra University, Visakhapatnam, India, in 1991 and 1994 respectively. He is also the first Head of the SSIU. Earlier, he worked in College of Engineering, Andhra University, and Centre for Remote Imaging Sensing and Processing (CRISP), The National University of Singapore in various positions during 1992-2001. He served as Associate Professor and Researcher in the Faculty of Engineering & Technology (FET), Multimedia University, Malaysia during 2001-07. His research interests include mathematical morphology, GISci, digital image pro-cessing, fractals and multifractals their applications in extraction, analyses, and modeling of geophysical patterns. He has published over 85 papers in journals, and has authored and/or guest edited 11 books and/or special theme issues for journals. He recently authored a book entitled "Mathematical Morphology in Geomorphology and GISci," CRC Press: Boca Raton, 2013, p. 546. He recently co-edited a special issue on "Filtering and Segmentation with Mathematical Morphology" for IEEE Journal on Selected Topics in Signal Processing (v. 6, no. 7, p. 737-886, 2012). His recent book on "Handbook of Mathematical geosciences: Fifty Years of IAMG", Springer Publishers, p. 942, 2018 crossed the downloads of 910000 within three years of its release. He is an elected Fellow of Royal Geographical Society (1999), Indian Geophysical Union (2011), Indian Academy of Sciences (2022), and was a member of New York Academy of Science during 1995-96. He received Dr. Balakrishna Memorial Award from Andhra Pradesh Akademi of Sciences in 1995, Krishnan Gold Medal from Indian Geophysical Union in 2002, and ‘Georges Matheron Award-2011 (with Lecturership)” of International Association for Mathematical Geosciences (IAMG), IAMG Certificate of Appreciation - 2018, and the IEEE Geoscience and Remote Sensing (GRSS) Distinguished Lecturer (DL) for 2020-2023. He is the Founding Chairman of Bangalore Section IEEE GRSS Chapter. He is on the Editorial Boards of Computers & Geosciences (Elsevier), Frontiers: Environmental Informatics, Mathematical Geosciences (Springer). More details about him can be seen at http://www.isibang.ac.in/~bsdsagar.

Two-Page Biography

B. S. Daya Sagar, MSc, PhD, FRGS (London), SMIEEE (USA), FIGU (India), FASc (India)
Qrt. B5, Indian Statistical Institute Campus, 8th Mile, Mysore Rd., RVCE PO, Bangalore - 560059, India.    Phone: +91-080-26985540 (O), +91-9880893291 (M); Email: bsdsagar@yahoo.co.uk, Homepage: http://www.isibang.ac.in/~bsdsagar

1. Education: B. S. Daya Sagar was educated in St Anthony School, Visakhapatnam, Government Arts College, and the Andhra University, India where he studied Earth Sciences (Shree Durga Prasad Saraf College of Arts and Applied Sciences, BSc, 1987, College of Engineering, MSc, 1991). He obtained PhD degree in 1994 from Andhra University for the thesis on Applications of Remote Sensing, Mathematical Morphology, and Fractals to Study Certain Surface Water Bodies.

2. Career: From 1991-2, he was a project assistant in a project 'PC-Based Image Processing System' at Department of Geoengineering, Andhra University College of Engineering; from 1992-4, a Senior Research Fellow of Council of Scientific and Industrial Research (CSIR); from 1994-5, a Research Associate of CSIR; from 1997-7, a Research Scientist/Principal Investigator in a Scheme for Extramural Research for Young Scientists funded by Ministry of Science and Technology; from 1998-8, a Senior Research Associate of CSIR; from 1998-2001, Gr-A Research Scientist in Centre for Remote Imaging Sensing and Processing (CRISP) in the National University of Singapore. He was appointed Associate Professor of Faculty of Engineering and Technology in the Multimedia University, Malaysia in 2001; Deputy Chairman of Centre for Applied Electromagnetics in 2003, serving until 2007. During 2007-13, he was an Associate Professor at Indian Statistical Institute-Bangalore centre, and during 2009-13, he was overseeing as the Founding Head of Systems Science and Informatics Unit at the Indian Statistical Institute-Bangalore Centre. Since 2013, he has been a Full Professor at the Indian Statistical Institute-Bangalore Centre. Since 2017, he has been a Visiting Professor at the University of Trento, Trento, Italy. In 20220, he has been promoted to the Professor (HAG) level.

3. Management experience: He is actively contributing his services for managing various administrative, academic, and professional activities.
3.1. Administration: While he was working at Andhra University, he (with Prof. SVLN Rao) set-up remote sensing and digital image processing laboratories at Centre for Remote Sensing, Andhra University. As a Deputy Chairman of Centre for Applied Electromagnetics, at Multimedia University-Malaysia, he developed a group of young researchers dealing with developing algorithms for surficial mapping and terrestrial characterization. As a Founding Head of Systems Science and Informatics Unit (SSIU) that was set up in 2009 at Indian Statistical Institute, he has set up Spatial Informatics Research Group that provides a forum for researchers, engineers, and practitioners in all applications that involve spatial information. He is a member of various examination, administrative, recruitment, promotional committees and Board of Studies, and has been a course coordinator for various subjects that he taught to undergraduate students.
3.2. Academic: He  was on adjudicating panels for over fifty PhD students, and numerous Master students. He secured funding from Govt. of India, French Govt., and Malaysian Govt during 1995-2018. He designed syllabus for elective subjects. On an average he reviews 10 papers a year for scientific and technical periodicals. He has organized over 10 international conferences, workshops, tutorials, summer/winter schools on the topics related to mathematical morphology and spatial informatics. Earth Science academic associations and societies received important contributions from Sagar, and has founded Bangalore Section IEEE Geoscience and Remote Sensing Chapter in India, under which several Lectures by Distinguished Lecturers are organized. He has been actively collaborating with foreign academics and scientists, not only for nurturing young students, but also for popularizing the subjects of mathematical earth sciences and the geospatial data sciences. Ten students under his supervision have been awarded PhD degrees. He has been involved in regular teaching subjects like remote sensing, digital image processing, mathematical morphology, and Geographical Information Science–at graduate and PhD levels from 1995. He delivered lectures both in India and abroad.
3.3. Professional: He guest edited seven important special issues of journals by collaborating with eminent academics from across the globe. He has edited or co-edited seven theme issues–"Mathematical Geosciences", "Quantitative Image Morphology", "Fractals in Geophysics", "Surficial Mapping", "Spatial Information Retrieval, Analysis, Reasoning and Modelling",  "Filtering and Segmentation with Mathematical Morphology", and " Applied Earth Observation and Remote Sensing in India"–for Journal of Mathematical Geosciences, International Journal of Pattern Recognition and Artificial Intelligence, Chaos Solitons & Fractals, IEEE Geoscience and Remote Sensing Letters, International Journal of Remote Sensing, IEEE Journal on Selected Topics of Signal Processing, and IEEE Journal on Selected Topics of Applied Earth Observation and Remote Sensing. He is serving as editor, associate editor, and editorial board member for reputed journals including Discrete Dynamics in Nature and Society: Multidisciplinary Research and Review Journal, Computers & Geosciences, Image Analysis and Stereology, Frontiers in Environmental Informatics, and Journal of Mathematical Geosciences

4. Research: Sagar has authored and / or edited eleven books,  and over 110 papers, out of which 85 papers appeared in International Journals. Spatial algorithms that Prof. Daya Sagar developed based on mathematical morphology, and fractals to handle the intertwined topics–(i) pattern retrieval, (ii) pattern analysis, (iii) simulation and modelling of terrestrial phenomena and processes, (iv) spatial reasoning, and (v) visualization–to address a range of questions of importance to mathematical geosciences, remote sensing, and geographical information science were a significant success–summarised in his recent monograph "Mathematical Morphology in Geomorphology and GISci". Most salient features of his contributions on the aforementioned five intertwined topics and beyond include the following:
4.1. Terrestrial Pattern Retrieval: Prof. Sagar has developed algorithms based on nonlinear morphological transformations (a) to extract valley and ridge connectivity networks from spatial data (e.g. Digital Elevation Model (DEM)), and the distinguishing feature of these methods is that they can be generalized to heterogeneous (e.g. highly complex terrain like fluvial landscapes) and homogeneous (less complex terrain like tidal flats) data, (b) to segment spatial data into zones of influence such as watersheds, physiographic features including mountains, basins, and piedmont slopes from Digital Elevation Models (DEMs), and (c) to quantify the degree of similarity between two spatial fields, which is useful for automatically rank the possible pairs of large spatial data sets into best-pair to worst-pair, and for the spatial data classification and clustering.
4.2. Terrestrial Pattern Analysis: Applications of spatial algorithms that he developed have highlighted the (a) evidence of self-organization via scaling laws which provide excellent agreement with geomorphologic laws such as Horton’s laws, Hurst exponents, Hack’s exponent, and other power-laws originally developed in a non-geoscientific context, (b) validity of his heuristically true arguments that the power-laws, which are scale-invariant, provide limited utility in understanding the geomorphologic processes, and these arguments further lead him to propose granulometric and morphologic shape decomposition based algorithms that yield scale-invariant but shape-dependent indices–which are more appropriate as what matters most in understanding spatial processes is shape–that could capture basic distinctions between topologically invariant geomorphologic basins, and (d) importance of a novel geomorphologic indicator, computed via a geodesic spectrum that provides unique one-dimensional geometric support, over the conventional width-function.
4.3. Simulation and Modelling: Algorithms to mimic the realistic spatio-temporal processes that Sagar developed by employing the bifurcation theory, fractal geometry, and nonlinear morphological transformations include (a) Fractal-Skeletal Based Channel Networks (F-SCNs) Model, as an alternate to the classic random models, generated for different shapes of fractal basins and their generalized Hortonian laws have been found to be in good accord with other established network models such as Optimal Channel Networks (OCNs) and real-world rivers, (b) modelling the geomorphologic process via morphological dilation and erosion, and their cascades through which he proposed the concept of discrete force and five laws of geomorphologic structures, (c) simulation of fractal landscapes that are geomorphologically realistic, and (d) discrete simulations based on the interplay between numeric and graphic analyses, he has shown various behavioural phases that geomorphologic systems – such as water bodies, folds, dunes, landscapes – traverse.
4.4. Spatial Reasoning: Using tools from mathematical morphology, Sagar developed efficient algorithms to (a) find ‘strategically significant’ spatial object(s) from a cluster of nonoverlapping spatial objects, (b) to compute origin-specific morphological dilation distances between spatial objects, which in turn can be used to determine directional spatial relationships between the spatial objects, and (c) develop modified gravity models to study the variable-specific interactions between the spatial zones for further classification in a hierarchical manner.
4.5. Visualization: The spatial algorithms that are of immense value in geographical information science, and in particular for spatiotemporal geo-visualization that he developed for (a) categorization of spatial-temporal maps via non-Euclidean metrics, (b) spatiotemporal modelling via hierarchical generation of median maps via morphological interpolations, (c) morphing  a source-spatial field into a target-spatial field via hierarchical median map computations, (d) convert point-specific non-contiguous data into zonal maps through the weighted skeletonization by zones of influence (WSKIZ) transformation, and (e) generating contiguous variable-specific cartograms via WSKIZ  thus solving a decade-long problem of preservation of global and local shapes of cartograms.

Prof. John Harbaugh of Stanford University in his Letter to the Editor of IAMG Newsletter highlighted the aforementioned work of Prof. Sagar -
"Today in the hinterlands, there are some mathematical geoscientists doing very original work involving applications that we'd barely thought about earlier. I'll mention one of today's pioneers, whose focus is on mathematical morphology of geological features, Daya Sagar of the Indian Statistical Institute at the Bangalore Centre. Notably he's been at it for two decades and has published a lot, including a seminal 546-page book in 2013 entitled "Mathematical Morphology in Geomorphology and GISci" that spans much of the field. Let's face it, the shapes or forms of geological objects are tantalizing, and some can be astoundingly complex. Landscapes, for example, often exhibit complex forms. Trying to describe their shapes alone can be challenging, but the greater challenge is to explain the processes and morphological forms that affect each other. Everyday features, such as stream meanders on broad floodplains, or lakes on floodplains with short lives, may be common, but they are not simple to categorize or analyze. All the while we're dealing with interdependencies between features and processes. Interdependencies are invariably accompanied by complex cyclic and chaotic behavior. So do you still want to make predictions? Take heart, though, because there are some new tools to help you, and that's where Daya's work is relevant".
His most recent monograph on "Handbook of Mathematical Geosciences", by Springer in July 2018 has crossed the downloads of 910000. In summary, his contributions in mathematical morphology and spatial geodata sciences evidenced through his research, teaching, educational, publishing, and editorial activities, and the ways in which his expertise has been applied to a range of questions of importance to mathematical geosciences and geoinformation science has offered a unique contribution.

5. Honours and Awards: For the accomplishments evidenced through his teaching wide across the globe, internationally acclaimed books, and research contributions published in international journals related to mathematical geosciences and spatial informatics, Prof. Sagar has already received several honours and awards. He was elected as a member of New York Academy of Sciences in 1995, as a Fellow of Royal Geographical Society in 2000, as a Senior Member of IEEE Geoscience and Remote Sensing Society in 2003, as a Fellow of the Indian Geophysical Union in 2011, and as Fellow of the Indian Academy of Sciences (in 2022. He is also a member of American Geophysical Union since 2004, and is a Member of the AGU's Honors and Recognition Committee (HRC) 2022-2023, and a life member of International Association for Mathematical Geosciences (IAMG) since 2006. Andhra Pradesh Academy of Sciences awarded him 'Dr. Balakrishna Memorial award in 1995 for his 'Attempt to Establish an Integrated Mathematical Approach to Study Certain Geoscientific Aspects'. He was awarded the Krishnan Medal of the Indian Geophysical Union in 2002 'for his Significant Studies in the Field of Applications of Remote Sensing, Mathematical Morphology, and Fractals to Study Certain Surface Water Bodies'. He was the only Asian conferred  'Georges Matheron Award - 2011 with Lectureship' of the IAMG for Outstanding Research Ability in the Field of Spatial Statistics or Mathematical Morphology, the Award of IAMG Certificate of Appreciation - 2018 for exceptional work on behalf of the IAMG, and the IEEE Geoscience and Remote Sensing Society (GRSS) Distinguished Lecturer (DL) for 2020-2023.

He, presently, lives in Bangalore with his wife Latha and sons Saketh and Sriniketh.

He can be reached via e-mail bsdsagar@isibang.ac.in, bsdsagar@yahoo.co.uk.

For more details regarding his research works and professional activities, his official homepage may be referred at http://www.isibang.ac.in/~bsdsagar/.