All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.



  • IDF files representing data of arbitrary dimensionality can be opened and saved. This enables reading and writing files with more dimensions than just x, y, layer, and time.

  • Added multi-species support for (imod.wq)

  • GDAL rasters representing N-dimensional data can be opened and saved similar to (imod.idf) in (imod.rasterio)

  • Writing GDAL rasters using ( and (imod.rasterio.write()) auto-detects GDAL driver based on file extension

  • 64-bit IDF files can be opened (

  • 64-bit IDF files can be written using ( and (imod.idf.write()) using keyword dtype=np.float64



[0.8.0] - 2019-10-14



[0.7.1] - 2019-08-07


  • "multilinear" has been added as a regridding option to imod.prepare.Regridder to do linear interpolation up to three dimensions.

  • Boundary condition packages in imod.wq support a method called add_timemap to do cyclical boundary conditions, such as summer and winter stages.


  • no longer fails on a single IDF when it is a voxel IDF (when it has top and bottom data).

  • imod.prepare.celltable now succesfully does parallel chunkwise operations, rather than raising an error.

  • imod.Regridder’s regrid method now succesfully returns source if all dimensions already have the right cell sizes, rather than raising an error.

  • imod.idf.open_subdomains is much faster now at merging different subdomain IDFs of a parallel modflow simulation.

  • no longer suffers from extremely slow execution when the DataArray to save is chunked (it got extremely slow in some cases).

  • Package checks in imod.wq.SeawatModel succesfully reduces over dimensions.

  • Fix last case in imod.prepare.reproject where it did not allocate a new array yet, but returned like instead of the reprojected result.

[0.7.0] - 2019-07-23



  • Namespaces: lift many functions one level, such that you can use e.g. the function imod.prepare.reproject instead of imod.prepare.reproject.reproject


  • All that was deprecated in v0.6.0


[0.6.1] - 2019-04-17


  • Support nonequidistant models in runfile


  • Time conversion in runfile now also accepts cftime objects

[0.6.0] - 2019-03-15

The primary change is that a number of functions have been renamed to better communicate what they do.

The load function name was not appropriate for IDFs, since the IDFs are not loaded into memory. Rather, they are opened and the headers are read; the data is only loaded when needed, in accordance with xarray’s design; compare for example xarray.open_dataset. The function has been renamed to open.

Similarly, load for IPFs has been deprecated. now reads both single and multiple IPF files into a single pandas.DataFrame.


  • imod.idf.setnodataheader


  • Opening IDFs with imod.idf.load, use instead

  • Opening a set of IDFs with imod.idf.loadset, use imod.idf.open_dataset instead

  • Reading IPFs with imod.ipf.load, use

  • Reading IDF data into a dask array with imod.idf.dask, use imod.idf._dask instead

  • Reading an iMOD-seawat .tec file, use instead.


  • Use np.datetime64 when dates are within time bounds, use cftime.DatetimeProlepticGregorian when they are not (matches xarray defaults)

  • assert is no longer used to catch faulty input arguments, appropriate exceptions are raised instead


  • sorts both paths and headers consistently so data does not end up mixed up in the DataArray

  • Return an xarray.CFTimeIndex rather than an array of cftime.DatimeProlepticGregorian objects

  • properly forwards nodata argument to write

  • idf.write coerces coordinates to floats before writing

  • Significant performance increase for reading IPF timeseries by specifying the datetime format

  • ipf.write no longer writes ,, for missing data (which iMOD does not accept)

[0.5.0] - 2019-02-26


  • Reading IDFs with the chunks option


  • Reading IDFs with the memmap option

  • imod.idf.dataarray, use imod.idf.load instead


  • Reading IDFs gives delayed objects, which are only read on demand by dask

  • IDF: instead of res and transform attributes, use dx and dy coordinates (0D or 1D)

  • Use cftime.DatetimeProlepticGregorian to support time instead of np.datetime64, allowing longer timespans

  • Repository moved from to


  • Notebook in examples folder for synthetic model example

  • Support for nonequidistant IDF files, by adding dx and dy coordinates


  • IPF support implicit itype