Plot Description:

This visualization mashes up the US Drought Monitor and three trailing day standardized precipitation index of your choice within a map presentation for a single state. SPI is computed by the simple formula of (accum - climatology) / standard deviation.

This autoplot is extremely slow to generate due to the on-the-fly calculation of standard deviation. As such, an optimization is done to sub-sample from available stations since the resulting map can only display a certain number of data points legibly. This means that the dataset you download from this page does not contain all available stations for a given state :/