QGIS 2.x Plugin
The Standardized Precipitation Index (SPI), a drought index widely used for drought monitoring is based on the probability of deficit in precipitation at any time scale. It is a simple and flexible drought index as it requires only precipitation as input data and it can quantify the degree of dryness/wetness on multiple time scales to address different types of droughts. Availability of free remotely sensed precipitation data makes the usage of SPI more convenient. This paper introduces SPI Utility, an open-source, light-weight and fast graphical user interface to generate yearly SPI values. It can generate SPI values for 1-, 3-, 4-, 6-, 9-, 12-, 24- and 36-month timescales for any specified month range. The tool can classify the generated SPI values into user-defined drought classes to generate the count and probability of occurrence of the drought classes. It can handle long duration precipitation data in form of both raster files and point data files. The tool can be used for drought monitoring and early drought warning systems.