Rescue and preservation of climate data by extraction and digitization from autographic weather charts using image processing tools

Data Rescue is the ongoing process of preserving all data at risk of being lost due to deterioration of the medium and digitizing current and past data into computer compatible form for easy access. IMD has conscientiously taken observations of the weather, recorded them either manually or automatically, transcribed them onto preset paper forms called autographic charts. Most of the charts are now at risk of being lost due to rapid deterioration of the medium. This paper presents algorithms for automatic extraction and storage of the atmospheric data using image processing tools. The key factors that influence the methods are speed, accuracy and space. We have tested the algorithms on scanned images of the autographic charts available at IMD and present the results in this paper.