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Each data point provides information on the agreement between the simulated head and the observed head.
Points that fall directly on the 45 degree line represent perfect agreement between the model and
measurement. Points above indicate a modeling result that is larger than the observed value, while points
below indicate a modeling result that is smaller than the observed value.

Statistical indicators are provided directly below the plot:

• Npts – the number of observational data point available for the comparison
• RMS Err – the root-mean-square error (units: meters)
• Mean Err – the mean error (units: meters)
• Nash-Sutcliffe E – the Nash-Sutcliffe coefficient (0 ≤ E ≤ 1)

Interpolation Methods. Because water level measurements in wells never/rarely occur at the location of am
model node, interpolation of simulated head values is needed to compare to observations. Three options are
available in MAGNET:

• 2D (traditional) bi-linear interpolation
• 3D Trilinear interpolation
• 3D Weighted interpolation for multi-layer models, where the weighting is determined by screen-
transmissivity (see Figure 6-10).

By default, 2D interpolation is used.

Figure 6-10: Scheme used for 3D Weighted interpolation of simulated head for comparison with observations.

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