GGU-SLUGTEST: "Autofit 1" menu item

If the "Type curves/Autofit 1" menu item is selected the program automatically compares the data with the existing type curves and searches for the best fitting type curve using the least squares method.

Please ensure that you do not have only a very few type curves in your type curves file, because the program will always find a type curve that fits best.

Before you can perform an "Autofit 1" you must specify in a dialog window which n^th data points of the data curve are to be compared to the type curves. Normally, you can work with the default setting "x = 1", i.e. every data point is included in the comparison. You can reduce the number of data points for very large datasets, by entering 10, for example. This makes things a little faster.

In addition, you can specify the range for H/H₀, that is, the region of the y-axis for which the fit is performed. The default range is from 0.02 to 0.98. The data often become noisy towards the end of a measuring campaign. This area can also be blanked out.

Confirm your input using the "OK" button. The program then searches without further ado for the best fitting type curve.

When the analysis is complete a window opens displaying the selected type curve parameter for your evaluation model. The maximum absolute deviation between the data curve and the type curve is calculated for this purpose. If you close the window with "OK", the type curve fit is drawn on the output sheet .

If, on the other hand, you press the "As onlytype curve" button, only the best fitting type curve is drawn on the output sheet with the data curve. Any existing type curves will be deleted.

When employing the "DOUGHERTY" and "MOENCH" models you must ensure that you really have generated the type curves most suitable for your aquifer and well geometry, using the menu item "Type curves/Generate".

If the type curves do not fit your geometry you will see an error message; you should not ignore this. Otherwise you will begin an evaluation with type curves unsuitable for your current configuration and the results may well be nonsense.