9.1.1 Merging and Splicing Data

These options are available from the Log Processing menu.

Log splicing and merging are advanced options that requires a passcode to activate.

Merging data.

A new dataset is created that contains all the curves from both datasets. The start and stop depths of the new dataset  will be the adjusted to include all the data in both input datasets. Null values are padded onto the extremities where no data was otherwise available

Splicing data.

The two input datasets need to have some depth overlap. Ideally, the same curves should be present in both datasets. During splicing, all curves with the same name are found in each dataset, and are spliced together.

If a dataset contains multiple curves with the same name, then only first curve is spliced. So to avoid confusion, the datsets should be prepared beforehand by removing curves with repeated names.

If a curve only exists in one of the datasets, then it is still included in the splice, but is padded with Null values.

When two curves are spliced a default order of precedence for splicing is set. If one the curves to be spliced is Null value, the order of precedence is to the curve that has a real value.

Non aligned sample depths

One problem that arises when merging and splicing data, is when the sample depths do not align at the same values. Most log data will have the sample depths at a value that is an integral number of times the sample rate.

For example, 1490 metres divided by 0.1524 = 9776.9028, whereas 1490.0148 metres divided by 0.1524 is 9777, so the depth of 1490.0148 is an integral number of times the sample rate. 

A 0.1524 m sampled depth sequence that includes 1490.0148 metres will also have 0.0000 m in the same sequence.

Splicing data and merging data when the depths do not exactly align (overlap) is not possible without shifting one of the inputs first.

If a dataset fails the criteria of non-integral times sample rate depth points, then it can be resolved by applying a Depth Shift of 0.0 m, and the select option to align sample depths to integral multiple of sample rate.