GPS-X Technical Reference

Miscellaneous 414
Figure 15-1 – Typical Time Series Plot of Predicted and Measured Data
MEASURED DATA TYPES
The time-series measured data is considered to contain, a time stamp at which the sample was
collected and a value of the data. The time-series data could be available in a regular or irregular
time intervals. The data measured at a wastewater plant could be from different type of sampling.
The following data types are common:
1. Grab Data: The sample is collected at a specific time. The on-line data and data from
grab samples belong to this category. The data point is fully defined by the time stamp
and the measured value.
2. Time proportional composite data: Equal volumes of samples are collected at regular
time intervals. These samples are mixed to give a composite sample. The data point is
completely defined by the duration of composite and time interval for sample collection.
3. Flow proportional composite data: Equal volumes of samples are collected at equal
volumes of wastewater treated. This means more number of samples is collected during
high flow conditions and lower number of samples during the low flow conditions. These
samples are mixed to give a composite sample. The data point is completely defined by
the duration of composite and volume interval for sample collection.
GPS-X Technical Reference