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When <mergeWithExistingSampleData>true<mergeWithExistingSampleData> is configured a reimported sample will be merged with the old data. Only the time series that where already present in the sample are overwritten the rest is added. Be careful with changing qualifiers when merging because changing a qualifier will result in a different time series. This "new" time series will be added to the sample and the "old" will remain, instead of overwriting the old with the new. Also sample properties can not be changed when merging because sample properties should be the same for the entire sample, this also applies to already and newly imported data for the same sample.
When re-importing samples make sure the location and time are exactly the same, since it is used as an internal id. Different samples with the same location time combination are handled internally by applying a behind the scene time shift in the storage, when samples are read this time shift is automatically corrected so the data will not suffer from this shift.
Details of the import format
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