DataArray - Arithmetic

We can basic arithmetic operations (plus, minus, multiplication and division) with DataArrays, both with scalars, numpy arrays and other DataArrays. The output will in all cases be a new DataArray.

import mikeio

fn1 = "../tests/testdata/oresundHD_run1.dfsu"
da1 = mikeio.read(fn1, items="Surface elevation")[0]
fn2 = "../tests/testdata/oresundHD_run2.dfsu"
da2 = mikeio.read(fn2, items="Surface elevation")[0]

Multiply or add scalar

We can scale a DataArray or add a constant using *, +, / and -

da1.values.mean()

0.18681714

da1_A = da1 + 1
da1_B = da1 - 1
da1_A.values.mean(), da1_B.values.mean()

(1.1868172, -0.81318283)

da1_C = da1 * 2
da1_D = da1 / 2
da1_C.values.mean(), da1_D.values.mean()

(0.37363428, 0.09340857)

Difference between two DataArrays

Assume that we have two calibration runs and we wan’t to find the difference…

da_diff = da1-da2
da_diff.plot(title="Difference");

da_diff = da1/da2
da_diff.plot(title="da1/da2");