GMS has included observation tools for a long time. These work with any numerical model and let you compare field observed data with model computed output. With transient data, the time of the observations doesn't necessarily match the model output times. In this case GMS would do a temporal interpolation to come up with a model calculated value.
When MODFLOW 2000 came out it included built in observations calculated when you ran MODFLOW. Now if the observation time didn't match the output time it didn't matter because MODFLOW would be sure to calculate an additional output at the observation time.
The residual errors calculated by MODFLOW have been available in GMS since shortly after MODFLOW started computing them but the GMS observation plots still behaved the old way, by doing a temporal interpolation. Until now. We just replaced the old way with the new and revamped several observation plots. The following images illustrate the difference.
|Old and busted. Notice the interpolation times of the upper and lower range don't always match the observation times.
|New hotness. Upper and lower bands replaced with fixed point-in-time box symbols. The color makes it easier to interpret.