Figure 2
From: Reconstruction of epidemic curves for pandemic influenza A (H1N1) 2009 at city and sub-city levels
Construction of epidemic curves using the original data (upper panel) and then by time series analysis after seasonal decomposition of time series by Loess (STL) and smoothing (lower panel). The procedure involved five steps of, firstly, detrending; secondly, cycle-subseries smoothing by loess; thirdly, low-pass filtering by moving average; fourthly, detrending by subtracting seasonal component; and finally, deseasonalizing.