Quality calculation for data points

In the chart display, data points of uncertain, bad, or unknown quality are visually highlighted with special indicators. The overall quality of a data point in a scatter plot depends on the quality of the two tag values of which it is composed. The following table shows the overall quality that results from each possible combination of tag qualities, assuming that both tag values aren't NULL. The top row contains the quality of the first tag, the left column contains the quality of the other tag.

For example, if one tag has good quality and the other tag has bad quality, the data point is highlighted with the indicator for bad quality.