Case study


1. Dataset

The format for the input sample data file is very straightforward. The minimum contents of it are two variables: date and the value of sample. The daily PM2.5 observed at US Embassy in the 423-day period from 10 May 2010 to 6 December 2011 is chosen as the sample data in this case. The text input file format is illustrated in Fig. 1-1, which shows the partial contents of the PM2.5 sample data in the csv file PM25.csv. The reference data PM10.csv contains PM10 observation in 18 official stations, published daily by the Beijing Municipal Environmental Protection Bureau (BJ-EPB) in the same time period with PM2.5 observation shared in Twitter. Fig. 1-2 shows some of the reference data.



Fig. 1-1 Table of sample data



Fig. 1-2 Table of reference data


2. Exercise

Step 1: The input data format should be similar to the above corresponding data format. Click 56D69}]YR02894}{MKAKVRH to import sample data and reference data respectively (see Fig. 2-1).


Fig. 2-1 SPA Model


Step 2: After loading the required data, as in Fig. 2-2, click “Run” button to execute the SPA model and save the result in CSV format. The computed result includes 6 variables: date, area estimation, model weight parameter w0, the standard deviation STDEV, one standard variance interval CI1 and CI2, shown in Fig. 2-3.


Fig. 2-2 Load data



Fig. 2-3 Computed area estimation and model parameters