Evaluation of Sprinkler Irrigation Uniformity by Double Interpolation Using Cubic Splines

An evaluation method, with accompanying software, was developed to precisely calculate uniformity from catch-can test data, assuming sprinkler distribution data to be a continuous variable. This has value in assessing application uniformity of sprinkler irrigation designs. Two interpolation steps are required to compute unknown water application depths at grid distribution points from radial distribution of catch-cans’ data: using both radial and peripheral interpolations. Interpolation by cubic splines was used to give accurately interpolated values. In theory, this method has higher accuracy compared with conventional methods to analyze catch-can data. Water application depths were calculated at each grid point and uniformity coefficients were computed from the grid distribution maps of water application depths.