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net.simplace.sim.transformers.LayerAggregationTransformer

It can compute the sum for absolute values (e.g. N content in g/m^2). It can compute the avg for relative values (as volumetric water content m^3/m^3).

Configuration

• method - aggregation method (currently only sum and avg are supported)
• depthfieldname - name of the field, that contains the depth \(d_i\) (lower boundary) of each layer
• maxdepthfield - optional: name of the field, that contains the maximum depth \(m\), up to which values should be aggregated

Calculation details

The transformer transforms all DOUBLEARRAY entries of the original resource and outputs the resulting doubles in the same order. The aggregation method is applied to all entries, it is not possible to define methods per entry.

The layer thickness d is calculated as \(t_0=d_0\) and \(t_i = d_{i}-d_{i-1}\) for \(i>0\)

As user-specified maxdepth can be smaller than the soil profile depth, for each layer the remaining depth is calculated \(r_i = max(m-d_{i-1},0)\), which is zero if the actual layer is completely below maxdepth. If maxdepthfieldid is omitted, then all layers are aggregated.

Sum of absolute values

Values from all layers, that are above maxdepth are summed up. From the layer that contains maxdepth, only the fraction from the upper boundary to maxdepth is summed up. \[\sum_{i=0}^{n-1}V_i \frac{min(t_i,r_i)}{t_i}\]

Average of relative values

Average values over the layers that are above maxdepth are computed by multiplying relative values with layer thickness d. From the layer that contains maxdepth, only the fraction from the upper boundary to maxdepth is used as weighing factor. Then the sum is divided by maxdepth m (or the total depth, if maxdepth m exceeds the soil profile depth). \[\frac{\sum_{i=0}^{n-1}V_i min(t_i,r_i)}{min(m,d_{n-1})}\]

Utilisation

The transformer is used by soilwater models that need soil properties per layer as well as aggregated properties for a specific depth, that contains multiple layers, e.g.

• Hillflow1D

Notice

The transformer is mainly designed for layered soil properties, but can be used also for other layered data that has a kind of 'depth' information (e.g. air temperature at different heights).

It transforms all numeric arrays of the resource and outputs them in the same order as they are specified in the resource. Non-array data in the resource is omitted in the transformer (except the keys).