SHTOOLS release notes: Version 4 | SHTOOLS

Version 4.12

New Datasets!

Added new ultra-high degree shape models of the Moon in both principal axis and mean Earth/polar axis coordinate systems (LOLA_shape and LOLA_shape_pa) and moved MoonTopo2600p to historical.
Added new ultra-high degree shape model of Mars (MOLA_shape) and moved MarsTopo2600 and MarsTopo719 to historical.
Added a new ultra-high degree shape model of Mercury based on the USGS SPG DTM (USGS_SPG_shape).
Added a new ultra-high degree shape model of Vesta based on the DLR SPG DTM (DLR_SPG_shape).
Added a new ultra-high degree shape model of Ceres based on the DLR SPG DTM (DLR_SPG_shape) and a high-degree shape model based on the JPL SPC DTM (JPL_SPG_shape).
Added historical degree-2 gravity models of Io, Europa, Ganymede, and Callisto derived from data collected by the Galileo mission.
Added two shape models of Titan (Mitri2014_shape and Corlies2017_shape) and a degree 5 gravity model of Durante et al. 2019 (Durante2019_gravity).
Added two gravity models of Enceladus (Iess2014_gravity and Park2024_gravity) and a high-degree shape model based on the JPL SPC DTM (JPL_SPG_shape).
Added two shape models of Eros (NLR_shape and SPC_shape) and the JPL gravity model JGE15A01.
Updated all constants to reflect the most recent datasets, and added new constant modules for Eros, Io, Europa, Ganymede, Callisto, Titan and Enceladus.
Added the property volume_equivalent_radius and volume to the constants modules.
Renamed the constant attributes density to mean_density and g0 to gravity_mean_radius.
Updated all datasets that download from zenodo to use the Pooch DOIDownloader.

Bug fixes

When importing an xarray grid with SHGrid.from_xarray(), check if the first row is 90 or -90 and flip accordingly.
Fixed a bug in SHCoeffs.convert() when coefficient errors are present.
Fixed a bug in spectralanalysis.cross_spectrum() when using real unnormalized coefficients.

Plotting improvements

Added the optional parameter rectangle to the SHGrid.plotgmt() method that allows the use of rectangular projections that are specified by the lower-left and upper-right coordinates.
Added the optional parameter cmap_background_foreground to SHGrid.plotgmt() that controls how data are plotted when they exceed the limits of the colormap.
Added the optional parameter title_offset to SHGrid.plotgmt() and SHGrid.plot() that specifies how much space to add between the plot and title.
Cleaned up the SHGrid.plotgmt() shading options based on changes made in pygmt 0.7, including the use of xarrays directly instead of creating temporary files.
Added the optional argument cmap_rlimits and cmap_rlimits_complex to SHGrid.plot(), SHGrid.plotgmt() and SHGrid.plot3d() to specify colorbar limits with respect to the maximum value of the data.
Added the optional argument cmap_scale to SHGrid.plot() and SHGrid.plotgmt() to allow using either a linear or logarithmic color map.
Add the optional argument cb_power to SHGrid.plotgmt() to allow plotting annotations as powers of 10.
Added an option to SHCoeffs.plot_spectrum() to plot the error spectrum (if present) or not.

Other changes

Added “ifx” to the list of possible Fortran compilers in the Makefile.
Added the optional argument r to SHMagCoeffs.expand() and SHGravCoeffs.expand() that allows one to compute the field at an arbitrary list of (r, lat, lon) points.
Allow the passing of pathlib.Path objects to all methods that require a filename.
Added jupyter-core as a build dependency in pyproject.toml.
Changed the behaviour of the fortan function MakeCircleCoord when the angular radius is zero.

M. A. Wieczorek, M. Meschede, A. Broquet, T. Brugere, A. Corbin, EricAtORS, A. Hattori, A. Kalinin, J. Kohler, D. Kutra, K. Leinweber, P. Lobo, J. Maia, D. Minton, I. Oshchepkov, P.-L. Phan, O. Poplawski, M. Reinecke, E. Sales de Andrade, E. Schnetter, S. Schröder, J. Sierra, A. Vasishta, A. Walker, xoviat, B. Xu (2024). SHTOOLS: Version 4.12, Zenodo, doi:10.5281/zenodo.592762

Version 4.11

Support for Python 3.12 using Meson

This version no longer relies on distutils (which was deprecated in python 3.12) and instead makes use of Meson and Meson-Python to build and test the pyshtools package. The package can be built from source using pip as before, however, if you need to create an editable install, it will be necessary to use the slightly modified command

pip install --no-build-isolation -e .

Please see the online documentation for instructions on how to run the test suites and benchmarks.

Other changes

We no longer use versioneer to determine the package version, but instead set the version in the main meson.build file using setuptools_scm. At the present time, it is not possible to determine the version when using a source tarball, and for this case, the build will fail. Please ensure that when building from source that you are doing so from a git versioned repository.
Fixed a problem with SHCoeffs.volume() when the coefficient normalization was ortho.
Fixed a potential LAPACK underscore problem when compiling with LAPACK_UNDERSCORE specified.
Minor changes were made to the python source files to ensure numpy v2 compatibility.

M. A. Wieczorek, M. Meschede, A. Broquet, T. Brugere, A. Corbin, EricAtORS, A. Hattori, A. Kalinin, J. Kohler, D. Kutra, K. Leinweber, P. Lobo, I. Oshchepkov, P.-L. Phan, O. Poplawski, M. Reinecke, E. Sales de Andrade, E. Schnetter, S. Schröder, J. Sierra, A. Vasishta, A. Walker, xoviat, B. Xu (2024). SHTOOLS: Version 4.11, Zenodo, doi:10.5281/zenodo.592762

Version 4.10.4

Bug fixes, minor enhancements, and deprecations

The module pyshtools.shtools has been removed, and is now accessible at pyshtools.backends.shtools.
Fixed a bug in the Fortran source code of MakeGravGradGridDH and MakeMagGradGridDH, both of which are used in the pyshtools tensor method of the classes SHGravCoeffs and SHMagCoeffs. This bug only affected the southern hemisphere, and is most noticeable close to the south pole.
Updated the urls for the Earth 2012/2014 datasets.
Changed the order of the imports in pyshtools/__init__.py that led to a circular import problem on some systems.
Updated how the shtools routines were wrapped using functools.wraps.

M. A. Wieczorek, M. Meschede, A. Broquet, T. Brugere, A. Corbin, EricAtORS, A. Hattori, A. Kalinin, J. Kohler, D. Kutra, K. Leinweber, P. Lobo, I. Oshchepkov, P.-L. Phan, O. Poplawski, M. Reinecke, E. Sales de Andrade, E. Schnetter, S. Schröder, J. Sierra, A. Vasishta, A. Walker, xoviat, B. Xu (2023). SHTOOLS: Version 4.10.4, Zenodo, doi:10.5281/zenodo.592762

Version 4.10.3

Minor packaging enhancement

The release modifies the way that the python doc strings are generated for the wrapped fortran functions. In previous releases the doc strings were generated at the time the package was built. Now, the doc strings are included directly in the repo, similar to the unix man pages. This minor change will help in making the macOS ARM conda builds, as well as in our transition from distutils to meson.

Future deprecation

The module pyshtools.shtools will be deprecated in the v4.11 release. This module represents 1 of 2 possible backends for pyshtools, and has been located at pyshtools.backends.shtools since version 4.9. Unless explicitly required, the user should avoid using the backends modules directly, and should instead call the routines that are located in the top level modules such as pyshtools.expand and pyshtools.rotate. Setting the backend by use of the routine pyshtools.backends.selected_preferred_backend() determines which backend to use when calling the routines in these top level modules.

M. A. Wieczorek, M. Meschede, T. Brugere, A. Corbin, A. Hattori, A. Kalinin, J. Kohler, D. Kutra, K. Leinweber, P. Lobo, I. Oshchepkov, P.-L. Phan, O. Poplawski, M. Reinecke, E. Sales de Andrade, E. Schnetter, S. Schröder, J. Sierra, A. Vasishta, A. Walker, xoviat, B. Xu (2023). SHTOOLS: Version 4.10.3, Zenodo, doi:10.5281/zenodo.592762

Version 4.10.2

Bug fixes and minor enhancements

Add the optional parameter lmax to pysh.SHWindow.to_shgrid().
Replace libtool by ar and ranlib in the fortran makefile.
Replace PWD by CURDIR in the main makefile.
Add method .change_units to the SHMagCoeffs class.
Copy all routines from the shtools module to backends.shtools (the top-level shtools module will be deprecated in v4.11).
Use pkg_resources instead of setuptools.version.pkg_resources in setup.py.
Fix a couple bugs where _np.int_ was mistakenly _np.int.
Move unix man pages from section 1 to section 3.
Modify fortran test programs to accept command line arguments, such as the location of the example data files and program input files.
Remove pypandoc as a dependency in setup.py and don’t convert the readme to reST format for pypi.
Add a Ganymede gravity model to the datasets module.
Minor updates to documentation and refactoring of the project README.

Future deprecation

Version 4.10.1

Bug fixes and minor enhancements

Simplify the code for backend management and improve handing of the default backend when ducc0 isn’t installed.
Changing the backend now changes which functions are referenced in the expand and rotate submodules.
Fix setup.py to work with all versions of setuptools.
Add the MarsTopo719 dataset for use in CI checks (using MarsTopo2600 often would timeout during download).
Fix a bug in SHGravRealCoeffs.expand and SHGravRealCoeffs.expand that did not correctly compute the radius of the flattened ellipsoid when an array of latitudes was provided.
Remove -static option from compiler options.
Convert some strings to raw format when they contain latex backslashes.
And other minor changes…

Future deprecation

M. A. Wieczorek, M. Meschede, T. Brugere, A. Corbin, A. Hattori, K. Leinweber, I. Oshchepkov, M. Reinecke, E. Sales de Andrade, E. Schnetter, S. Schröder, A. Vasishta, A. Walker, B. Xu, J. Sierra (2022). SHTOOLS: Version 4.10.1, Zenodo, doi:10.5281/zenodo.592762

Version 4.10

Enhancements

Change the preferred backend from ‘shtools’ to ‘ducc’ (when both are available).
Link routines in top level modules pyshtools.expand and pyshtools.rotate to the corresponding backend routines.
Add historical lunar topography dataset GLTM-2B.
Add historical martian magnetic field models FSU50 and FSU90.
Add new Mars gravity model MRO120F as well as several historical Mars gravity models.
Add historical Venus topography datasets SHTJV360A01 and SHTJV360A02.
Add Thebault2021 Earth magnetic field dataset.
Add Mars topography dataset MarsTopo719, which is a truncated version of MarsTopo2600.
Update urls for databases hosted at GSFC.
Reorder optional arguments in docs for makegravgradgriddh and makemaggravgradgrid for consistency with code.
Allow shtools and dov file formats to contain floats for degree and order.
Minor changes and enhancements to the documentation.

Bug fixes

Fix typo regarding nthreads in SHMagCoeffs.rotate() method.
Fix bug with SHGravCoeffs.admittance() when using function=geoid.
Fix bug in python wrapper of the routine MakeGrid2D concerning the mandatory variable interval.
Add workaround to use pygmt with shading for versions >=0.4.
Convert all grids to float before using the ducc backend.
SHGeoid.to_netcdf() now outputs double precision by default (consistent with the other grid classes).
Fix bug with SHWindow.multitaper_cross_spectrum() when using arbitrary localization regions.
Fix bug with the c-wrapper for cMakeGradientDH regarding the optional radius parameters.
Minor changes to remove deprecation warnings.

Future deprecation

Version 4.9

Backends

Implemented the option to use a different backend when performing certain operations requiring spherical harmonic transforms. At present, only ‘shtools’ (default) and the Distinctly Useful Code Collection (‘ducc’) are supported.

Introduced a new module backends that has functions allowing the user to control which backend is used. To set the backend for all subsequent operations, use backends.select_preferred_backend().
Added the optional parameters backend and nthreads (‘ducc’ only) to all methods of the pyshtools classes that allow multiple backends (such as SHGrid and SHCoeffs).
Added a new backends web documentation page that describes the use of the new module.

Plotting routines

Added the new methods SHGrid.histogram() and SHGrid.plot_histogram() for generating area-weighted histograms.
Renamed a few instances of variable names used in the plotting routines from title_labelsize to titlesize for consistency. This affects the methods Slepian.plot_coupling_matrix(), Slepian.plot_spectra(), and SHWindow.plot_coupling_matrix().
Modified some plotting routines so that fontsizes can be specified using standard matplotlib strings.
Replaced the deprecated matplotlib get_geometry with get_subplotspec.
Replaced the pygmt option I with the alias shading for colorbars.

IO and datasets

Updated the Venus rotation period using data from Margot et al. (2021).
Renamed constants variables r to mean_radius (but kept r as an alias for backwards compatibility).
Improved the reading of ICGEM formatted files of gravitational potential models. Fixed a bug where the time variable contribution was not computed when the coefficients had an associated trnd or dot term. When a line in the data section starts with an unknown key, a warning is now printed to the screen (which can be turned off by specifying quiet=True). For files formatted as icgem2.0, time variable terms were simply ignored if the specified epoch fell outside of the allowed range. Now, the routine will instead raise an error. Finally, the documentation was improved by describing the allowable keyword entries of the header and data section of the file.
Added the option encoding for all routines and methods that read or write text-based spherical harmonic files.
Hard coded all datasets to use utf-8 in order to avoid problems with the XGM2019E dataset that has a character that can not be decoded by the GBK encoding that is the default in some Chinese installations.
Added a few historical lunar gravity fields to the module datasets.Moon.historical.gravity.

Other changes

Add a C wrapper for the function MakeGradientDH().
Changed the default behavior of the Fortran routine MakeGradientDH() and SHCoeffs.gradient(). The original behavior was to compute the gradient on a sphere of radius r, where r was the degree 0 coefficient of the function. The new behaviour is to compute the gradient on the unit sphere. This radius can be modified by supplying the optional argument radius.
Added the option ‘per_lm’ for generating random spherical harmonic coefficients in the .from_random() methods of SHCoeffs, SHGravCoeffs, and SHMagCoeffs.
Fixed two bugs related to complex spherical harmonic transforms. First, for complex grids, the last coefficient coeffs[1, lmax, lmax] was in error when lmax was odd and when using DH grids. Second, when using SHGrid.expand() with grid type DH2 the parameter sampling=2 was not passed to the Fortran routine.
Updated makefile install to include example data files, and to place them in the correct directories when installing with homebrew.
Updated a few dependencies, including astropy>=4.0 and pygmt>=0.3.0.
Fixed a floating point error-caused bug in SHGrid that could arise if the value input to arccos was greater than 1.
Converted np.float_ and np.complex_ to np.float64 and np.complex128 to avoid numpy deprectation warning.
Added threadsafe to numpy signature files.

M. A. Wieczorek, M. Meschede, T. Brugere, A. Corbin, A. Hattori, K. Leinweber, I. Oshchepkov, M. Reinecke, E. Sales de Andrade, E. Schnetter, S. Schröder, A. Vasishta, A. Walker, B. Xu (2021). SHTOOLS: Version 4.9, Zenodo, doi:10.5281/zenodo.592762

Version 4.8

Several functions have been vectorized using numpy.vectorize(). These include: spharm_lm(), legendre_lm(), MakeGridPoint(), MakeGridPointC(), DownContFilterMA(), DownContFilterMC(), NormalGravity(), SHConfidence(), and PlmIndex().
A new Fortran routine MakeGradientDH was added to compute the horizontal gradient of a real scalar function. The method .gradient() was added to the SHCoeffs class, and a new class SHGradient was created to store and plot the two horizontal components of the gradient.
Added new Fortran functions MakeGravGridPoint and MakeMagGridPoint to compute the gravity and magnetic field vector at a single point.
Added the option to compute the gravity and magnetic field vectors at a single point using the python class methods SHGravCoeffs.expand() and SHMagCoeffs.expand().
The plot_spectrum2d() routines have been updated to include more plotting options, including placement of the origin, tick intervals, and colormaps. Most optional parameters are the same as in the SHGrid.plot() method.
Added the option to including intensity shading in the SHGrid.plotgmt() routine. The shading can be derived from the gradient of the input grid (by setting shading=True) or from a different map by supplying an SHGrid class instance. Optional parameters include the azimuth of the shading (shading_azimuth), as well as the maximum amplitude of the intensity (shading_amplitude).
Modified all the Fortran routines to use a slightly more efficient way to compute the radius of an ellipsoid as a function of geocentric latitude.
Fixed a bug in SHCoeffs.expand() when colat was specified in radians.
All declarations of integers in the Fortran code are now made using the types defined in the module iso_fortran_env. Furthermore, the python wrapper and signature files have been updated to be explicit when defining the Fortran variables.
Fixed a bug where the old module name constant needed to be updated to constants in the method SHCoeffs.centroid().
Corrected the parameterization used when generating ellipsoids in SHGrid.from_ellipsoid(). Though this method was introduced in v4.7, it was not mentioned in the release notes.
Changed the default behavior of SHCoeffs.to_array() so that the default value is not to return the errors by setting errors=False.
Added the optional attribute name to the coefficient classes SHGrid, SHGravCoeffs, SHMagCoeffs and SlepianCoeffs. All datasets now explicity set name to the function call of the dataset.
Moved the file shtools.h from src/ to include/ and updated the Makefiles accordingly.

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, A. Corbin, I. Oshchepkov, B. Xu, and A. Walker, A. Hattori, S. Schröder, K. Leinweber, A. Vasishta (2021). SHTOOLS: Version 4.8, Zenodo, doi:10.5281/zenodo.592762

Version 4.7.1

Minor modifications were made to the Makefiles in order to submit shtools to the homebrew-core and macports package managers. Relative paths were removed in a few cases by explicitly passing variables such as $(MODPATH)$ to all dependent sub-makefiles. Default variables are no longer set in the sub-makefiles, as these are not intended to be used independently: All variables are passed directly from the main Makefile. Renamed the directory modules to include to be consistent with macports and homebrew installations. The F95FLAGS are set by searching if the compiler name contains the “short” compiler name. This allows recognizing “gfortran-10” as being “gfortran”.
Added a .github folder with templates for issues and releases checklists.
Converted matplotlib relative font sizes (such as ‘large’) to points when passing font sizes to the Cartopy and pygmt plotting routines.
Minor changes to the Travis configuration file, the conda environment.yml file, and fortran documentation and man pages.
Added initial experimental support for C-binded SHTOOLS wrapper functions. This includes replacing assumed-size arrays with fixed-size arrays with additional arguments for each dimension. Though this is not yet documented, a working example can be found in the folder examples/cpp.

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, A. Corbin, I. Oshchepkov, B. Xu, and A. Walker, A. Hattori, S. Schröder, K. Leinweber, A. Vasishta (2020). SHTOOLS: Version 4.7.1, Zenodo, doi:10.5281/zenodo.592762

Version 4.7

Datasets

The new datasets module allows users to easily download spherical harmonic coefficient datasets and return them as SHCoeffs, SHGravCoeffs or SHMagCoeffs class instances.

To load a dataset, call the relevant method as in these examples:

    hlm = pysh.datasets.Venus.VenusTopo719()  # Venus shape
    clm = pysh.datasets.Earth.EGM2008()  # Earth gravity
    glm = pysh.datasetes.Earth.WDMAM2_800()  # Earth magnetic field
    clm = pysh.datasets.Moon.GRGM1200B()  # Gravity of the Moon

Better IO routines

Added the functions (in the module shio) shwrite(),read_dov() write_dov(), read_bshc(), write_bshc() and write_igcem_gfc() to read and write ‘shtools’, ‘dov’, ‘bshc’, and ‘icgem’ files.
Added the function shio.read_igrf() for reading IGRF formatted files, and returning coefficients for a specified year.
The SHCoeffs, SHMagCoeffs and SHGravCoeffs methods to_file() and from_file() now accept all file formats.
Added support for reading gzip and zip files in shread, SHCoeffs.from_file(), SHGravCoeffs.from_file(), SHMagCoeffs.from_file(), and read_icgem_gfc()
Fixed a minor bug where netcdf files would not accept boolean attributes.

Amittance and correlation methods

Added the methods admittance(), correlation() and admitcorr() for the classes SHCoeffs, SHGravCoeffs, and SHMagCoeffs to compute the admittance and/or correlation with another function.
Added the methods plot_admittance(), plot_correlation() and plot_admitcorr() to easily plot these functions.

Better plotting routines

Added the option legend_loc to most plotting routines to allow fine control over where the legend is placed.
Minor bug fixes concerning colorbar parameters cb_offset and cb_triangles.

Better treatmentment of uncertainties

Added the option to include error coefficients in the class SHCoeffs.
Added the boolean option errors to the method to_array() in order to control whether the error coefficients are returned with the function spherical harmonic coefficients.
Added the option legend_error to the SHCoeffs, SHMagCoeffs and SHGravCoeffs method plot_spectrum() to provide a customized legend entry for the error spectrum.

New attributes for SHCoeffs, SHGravCoeffs and SHMagCoeffs

Added the attribute error_kind to specify the type of errors.
Added the attribute units to all grid and coefficient classes.
Added the attribute epoch to SHGravCoeffs, SHGravGrid , SHGeoid and SHTensor.
Added the attribute year to SHMagCoeffs, SHMagGrid , and SHTensor.

Improved Documentation

The web documentation has been broken into two separate components: pyshtools (python) and SHTOOLS (Fortran 95).
Reorganized the web documentation for clarity (re-organization of tutorials and guides, creation of a separate page for shtools grid formats, creation of separate pages for datasets, constants, and spherical harmonic coefficient file coeeficients).
The python tutorial notebooks are now rendered by the jupyter nbviewer web page. From this viewer, the user can easily download the notebook, or run it in a binder session.
Updated the documentation for installing pyshtools using Conda.

Initial support for fpm

Initial experimental support is added for use with fpm: the fortran package manager.

To install as a stand-alone project, it is only necesssary to use the command

fpm build

This will place the necessary .mod and .a files in a subdirectory of build.

To include shtools as a dependency in a project that compiles with fpm, you only need to add the following to the fpm.toml file:

[dependencies]
SHTOOLS = {git="https://github.com/SHTOOLS/SHTOOLS.git"}

In the current state of fpm (which is undergoing active development), it is not possible to link to system wide libraries, such as fftw and lapack, which are required by shtools.

Other changes

Added error checks to the pyshtools function YilmIndexVector.
Renamed the constant module to constants, and reogranized the constants in a more logical way (i.e., constants.Mars.r instead of constants.Mars.r_mars).
Added a gmt xarray accessor for use with pygmt.
Fixed a bug in Curve2Mask python wrapper when using extended grids, and fixed a bug in the fortran code when the input file contained points at exactly 0 or 360 degree.
pyshtools versioning is now done using versioneer, instead of the homemade system that was in the setup.py (which was somewhat complicated and needed to set ISREALESED to True or False). Versioneer gets the version number automatically from git tags.

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, I. Oshchepkov, B. Xu, and A. Walker, A. Hattori, S. Schröder, K. Leinweber, A. Vasishta (2020). SHTOOLS: Version 4.7, Zenodo, doi:10.5281/zenodo.592762

Version 4.6

New extended grids

All grid formats now allow to compute the redundant values at 360 E longitude (GLQ and DH), as well as at 90 S (DH only). These extended grids are now the default in pyshtools, but remain optional in the Fortran 95 routines. The use of extended grids is controlled by the optional argument extend. The purpose of these extended grids is to better integrate with the plotting routines that require these points (i.e.., Cartopy and pygmt).

Improved plotting and map projections

The plotting routine SHGrid.plot() has been refactored to allow support for projections using Cartopy and pygmt.

An incorrect 0.5 pixel offset was fixed when plotting grids via matplotlib, and grids now correctly plot both 0 and 360 degrees using the new “extended” grids of SHGrid.
Support was added for Cartopy projections, by specifying: SHGrid.plot(projection=ccrs.ProjectionName()).
The argument colorbar now takes the options ‘top’, ‘bottom’, ‘left’ or ‘right’.
Improved plotting and placement of colorbars. New optional arguments include cb_label for labels, cb_ylabel for a label on the y axis of the colorbar, cb_tick_interval for specifying the major tick interval, cb_minor_tick_interval for specifying minor tick intervals, cb_triangles for plotting upper/lower limit triangles at the ends of the colorbar, cb_width to specify the colorbar width, and cb_offset to override the default spacing between the map and colorbar.
Improved colormap handling: New optional arguments include cmap_limits to specify the lower and upper bounds of the data, as well as an interval for constant color intervals, and cmap_reverse to reverse the colormap.
Improved handling of ticks and annotations: The optional argument ticks specifies which ticks and annotations to show, using a syntax from the generic mapping tools (i.e., 'WSen').
Experimental support for pygmt using the routine SHGrid.plotgmt(). This function takes nearly the same arguments as plot(). As soon as pygmt implements projection classes (https://github.com/GenericMappingTools/pygmt/pull/379), this will be incorporated into the plot function in the same manner as Cartopy was.
All gravity, magnetics, tensor, localization windows and slepian function plotting routines incorporate these changes.
Added a new introductory notebook that shows how to use all features of the plot() function.

Improved integration with xarray DataArrays, xarray DataSets, and netcdf files

Added the methods to_netcdf() and from_netcdf() to the SHCoeffs, SHGravCoeffs and SHMagCoeffs classes.
Added the method SHGrid.from_xarray() to initialize a grid from an xarray DataArray.
Added improved descriptive attributes for netcdf files that mirror these conventions.
Added the method SHGeoid.to_xarray() to export an xarray DataArray and to_netcdf() to export a netcdf object readable by the generic mapping tools.
Added the methods SHGravGrid.to_xarray() and SHMagGrid.to_xarray() to export all gridded data (radial, theta, phi, total, and potential) as an xarray DataSet.
Added the methods SHGravTensor.to_xarray() and SHMagTensor.to_xarray()to export all gridded data (Vxx, invariants, eigenvalues) as an xarray DataSet.

Gravity routine improvements

Added the method SHGravCoeffs.center_of_mass to calculate the center of mass of a body.
Added the method SHGravCoeffs.inertia_tensor() to calculate the moment of inertia tensor.
Added the Earth dynamical flattening constant H (IERS Conventions 2010) to the constant module.
The read_icgem_gfc() function was extended with the option encoding as some models in ICGEM are not in UTF-8.
Addded the method centroid() to the class SHCoeffs. The centroid is computed as the center of mass of a homogeneous object.

Other changes

New methods SHGrid.to_real() and SHGrid.to_imag() return the real and imaginary components of a complex SHGrid instance.
Added an optional argument copy to SHCoeffs.pad().
Fixed bugs in the Fortran code of PlBar_d1 and PlON_d1 when calculating the Legendre polynomials at the north and south pole.
Spherical harmonic coefficients can be read remotely by specifying a URL as the filename. This functionality uses requests.get(), and has been implemented in the function shread() and the SHCoeffs method from_file().
Fixed a bug in the fortran code of Curve2Mask. As part of this fix, the optional parameter centralmeridian has been removed as it is no longer required. The longitudes of the curve can possess values from -360 to 720 degrees, and the routine searches for discontinuities that may occur between two successive points as the longitudes pass from 360 to 0, or -180 to 180 degrees.

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, I. Oshchepkov, B. Xu, and A. Walker, A. Hattori, S. Schröder, K. Leinweber, A. Vasishta (2020). SHTOOLS: Version 4.6, Zenodo, doi:10.5281/zenodo.3698050

Version 4.5

SHCoeffs

Added cross_spectrum(), plot_cross_spectrum() and plot_cross_spectrum2d() methods to the SHCoeffs class.
Added from_cap() constructor to create coefficients of a spherical cap.
Fixed a small bug when rotating coefficients in the SHCoeffs, SHMagCoeffs and SHGravCoeffs classes when the input csphase is different from the default value.

SHGrid

Added the method from_zeros() to initialize a grid with zeros.
Added the method from_cap() to initial a grid with a spherical cap.
Added support for saving gridded data to netcdf and xarray formats. to_netcdf() exports data to netcdf format, and when saved to file can be used directly with GMT (generic mapping tools) where they are known as ‘grd’ files. to_xarray() exports data to an xarray DataArray.
Fixed a type error when expanding complex coefficients at arbitrary points.

Slepian functions

Added the fortran function SHSCouplingMatrix and Slepain class method coupling matrix() for computing the coupling matrix that relates the Slepian expansion power spectrum to the global power spectrum.
Added the fortran function SHSCouplingMatrixCap which is optimized for working with spherical cap Slepian functions.
Improved the plotting capabilities of the method plot_coupling_matrix, such as the addition of colorbars, and the option to normalize to maximum value to unity.
Added the option taper_degrees() and slepian_degrees() to the SHWindow and Slepian classes, respectively, to allow for the construction of Slepian functions that exclude certain spherical harmonic degrees.
Added the fortran function SHMTVar and the SHWindow class method variance() to compute the variance of a multitaper spectral estimate (based on SHMTVarOpt).
Added the fortran function SHSlepianVar and the Slepian class method variance() to compute the variance of a Slepian expansion spectral estimate.
Improved the handing of the optional parameter weights in all methods of SHWindow.
Changed the name of the optional parameter nwin of SHWindow.coupling_matrix to k for consistency with the localized spectral analysis routines.

Fortran 95

The Fortran code was modified to be strictly compliant with the f95 standard (-std=f95 in the gfortran compiler). Double precision, double complex, and long integers are defined as real(dp), complex(dp), and integer(int8), and the types are defined in a new module ftypes.f95.
A few intrinsic function calls have been renamed to conform with the standards, and all double precision constants are now defined by appending _dp to them.

FFTW

The syntax of the fftw routines has been updated. In particular, the old call dfftw_execute(plan) statements now include all their dependent variables using the new syntax call fftw_execute_dft(plan, grid, coef). Importantly, the old syntax caused the GCC9 optimizer to break the spherical transform routines, generating meaningless output for large parts of the grids or coefficients.
The fortran routines now access the FFTW library using Fortran 2003 standards. Though most compilers do not yet support all features of F2003, the few features used here (such as the module iso_c_binding) are claimed to be supported by the majority of modern compilers. This allows us to access the FFTW routines without use of fortran bindings, which are not always included in compiled versions of FFTW.
All FFTW routines are explicitly defined in an interface block in FFTW3.f95. For simplicity, the use of the optional parameter FFTW_UNDERSCORE used in the Makefile has been deprecated.

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, I. Oshchepkov, B. Xu, and A. Walker (2019). SHTOOLS: Version 4.5, Zenodo, doi:10.5281/zenodo.2350781

Version 4.4

New Slepian expansion routines

Added the new Fortran 95 functions SHRotateTapers for rotating spherical cap Slepian functions, SlepianCoeffs for expanding a function in a Slepian basis, and SlepianCoeffsToSH to convert the Slepian coefficients into spherical harmonic coefficients.
Added two python classes Slepian and SlepianCoeffs for managing Slepian basis functions and the Slepian expansion coefficients of a function.

Legendre and spherical harmonic convenience functions

Added 4 python convenience functions for computing Legendre and spherical harmonic functions: legendre() to compute all the legendre functions, legendre_lm() to compute the legendre function for a specified degree and order, spharm() to compute all the spherical harmonic functions, and spharm_lm() to compute the spherical harmonic functions for a specific degree and order.

Other improvements

Added the option to perform a weighted least squares inversion in the fortran routine SHExpandLSQ, and added a python wrapped function SHExpandWLSQ().
Added min() and max() methods to the SHGrid class, to return the minimum and maximum value of the gridded data.
Added the property mass to the SHGravCoeffs class, which is computed by the input GM and the codata value for G.
Add the optional parameter omega to SHGravCoeffs.geoid() to override the value provided in the class instance.
Fixed some minor typos and usability issues, and cleaned up the python wrapper and signature files.

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, I. Oshchepkov, B. Xu, and A. Walker (2018). SHTOOLS: Version 4.4, Zenodo, doi:10.5281/zenodo.592762

Version 4.3

New Gravity and Magnetic field classes

Added gravity classes SHGravCoeffs, SHGravGrid, SHGravTensor and SHGeoid.
Added magnetic field classes SHMagCoeffs, SHMagGrid, and SHMagTensor.
Added new fortran subroutine MakeMagGradGridDH, which is analogous to MakeGravGradGridDH.
Reorded the arguments of CilmPlusRhoHDH to be consistent with CilmPlusDH.
The python routine MakeMagGridDH now also outputs the magnetic potential as a grid.

Better figures

Addition of the function pyshtools.utils.figstyle(), that sets several matplotlib parameters for better figures. This function takes as optional parmeters the maximum useable width of a journal page, the relative width of the figure with respect to this value, and the screen resolution in dpi.
Most plotting routines have optional parameters to set minor tick intervals, grids, label font size, and tick font size.
Degree symbols are plotted on tick labels for maps.
examples/python/Common/FigStyle.py was removed from the examples.
Added the options vmin and vmax to the plotting methods SHCoeffs.plot_spectrum2d() in order to specify the limits of the color scale.
Added the option to plot colorbars on SHGrid plots, along with the option to specify their orientation and a text label.
All notebooks have been updated.

New constant subpackage

The constant subpackage has been completely rewritten and now makes use of the astropy Constant class. This class has attributes name, value, uncertainty, unit, and reference. The naming of the constants has changed in some cases for consistency. A few constants that are not necessary were removed. Many of the constants were updated with more recent values. Constants can be used in arithmetic operations with either other Constants or with objects of the astropy class Quantity.
Constants are organized into modules for each of the planets (Mercury, Venus, Earth, Moon, and Mars), and for convenience, these are all added to the main namespace. The fundamental constants G and mu0 from the astropy constants package were added (as taken from CODATA 2014).

Other changes

Fixed a bug in how the random coeffcients were determined for unnormalized coeffcients in SHCoeffs.
Optional parameter seed added to SHCoeffs.from_random() to allow for reproducibility.
One can now specify colat instead of lat for the method SHCoeffs.expand().
Added __repr__ methods to all pyshtools classes.
Changed the mathematical operators of SHCoeffs such that addition and subtraction of a constant only affects the degree 0 term.
Added the optional parameter lmax to SHCoeffs.plot_spectrum() and SHCoeffs.plot_spectrum2d().
Fixed a bug in SHCoeffs.pad() where the attribute mask was not similarly padded.
For mathematical operations with SHCoeffs grids, it is now required that the two class instances have the same lmax.
Clarified the documentation of SHRotateCoef to point out that this is only valid for intrinsically real functions that are expressed in complex harmonics.
Added the method volume() to the class SHCoeffs, that calculates the volume of the object.
Added the attributes area and shannon to SHWindow, which provides the area of the concentration domain and the shannon number.
Removed python installation support from Makefile: use pip instead.

Citation:

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, I. Oshchepkov, B. Xu, and A. Walker (2018). SHTOOLS: Version 4.3, Zenodo, doi:10.5281/zenodo.1346663

Version 4.2

Change log:

Full support added for the use of unnormalized harmonics in the classes SHCoeffs and SHGrid. To make use of this normalization, just specify normalization='unnorm'.
Added a new python native routine mag_spectrum() in the subpackage gravmag that replaces the original fortran wrapped routines. The old python wrapped functions have been removed from pyshtools. This new routine is nearly the same as spectrum(), and further allows one to compute the spectrum of the potential or magnetic intensity.
The old fortran based SHRead function has been replaced with a python native version shread(). The functionality is nearly identical as before, and combines the previous routines SHRead, SHReadError, SHReadErrorH and SHReadH into one. Differences include: (1) It is no longer necessary to specify the lmax of the file: This is determined automatically by reading the file from the end, (2) both real and complex coefficients are supported, (3) a header line can be output, but it is a simple list of type str that will need to be converted to the correct format by the user, and (4) “comment” lines are read and ignored: A valid line is one where there are 4 or more words, and where the first two words are integers.
A new python native function convert() was added in the subpackage shio that converts between arrays of spherical harmonic coefficients with different normalizations. The class SHCoeffs was then simplified by using this external function for all conversions involving SHCoeffs class instances.
The optional parameter lmax was added to SHCoeffs.spectrum().
When plotting grid from the class SHGrid, one can now specify the label to use for the x and y axes with xlabel and ylabel, as well as the interval to use when plotting ticks on both axes using tick_interval.
The pyshtools rotation routines now allow you to specify the optional parameter convention to treat Euler angles in either the x or y conventions (i.e., which axes to use for the second rotation). Furthermore, the optional argument body allows you to specify if you want to rotate the body (True), or coordinate system (False, default). The tutorial number 3 was updated to clear up some inconsistencies in how the angles were defined.
New optional parameters added to SHWindow.plot_windows() and SHWindow.plot_spectra() that include xlim and ylim for the limits when plotting spectra, maxcolumns for the number of columns to use when plotting several windows, and lmax which controls the grid spacing when plotting the windows.
Added the optional argument lmax to SHCoeffs.from_random() that allows you to create coefficients with maximum bandwidths that are either greater or less than the bandwidth of the input power spectrum.
Added a warning message when using SHCoeffs.rotate() with degrees greater than 1200, as the routine is not accurate beyond this value.
Added an optional argument legend to SHWindow.plot_windows() to control whether the legend is plotted or not.
Fixed a minor bug in ClassExample.py file concerning the use of SHCoeffs.rotate().
Added support for plotting to an already existing figure by allowing the user to specify an existing matplotlib axes.
Removed some non-standard ascii dashes in the documentation files, and forced all doc files to be opened as utf-8.
HTML documentation was completely redone using Jekyll. The markdown source files are now located in pages/mydoc. A static html web site is built using jekyll, whose files are located in doc. Github will automatically create the static pages and serve them on shtools.github.io/SHTOOLS. To build the static pages yourself, it is only necessary to execute bundle exec jekyll build in the directory doc, which will build the site into _site in the same directory. Alternatively, make www in the main directory will create a static site in the top-level directory www that could be used to deploy on a different web server. The site is based on the template Jekyll documentation theme by @tomjoht.

Citation:

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, I. Oshchepkov, B. Xu, and A. Walker (2018). SHTOOLS: Version 4.2, Zenodo, doi:10.5281/zenodo.1250054

Version 4.1

This version adds improved functionality to SHTOOLS and fixes a couple of minor bugs. In addition, this release will be the first where pre-built wheels for unix/macOS/windows will be distributed via PYPI.

Change log:

Added an optional argument lmax to SHCoeffs.from_array().
Coefficients are zero-padded when lmax is greater than the maximum degree in SHCoeffs.to_array().
The method pad() was added to the SHCoeffs class that zero pads or truncates the coefficients to a different lmax.
Fixed the method SHCoeffs.from_file() such that the maximum spherical harmonic degree of the class is the maximum spherical harmonic degree of the coeffs (and not lmaxin as before).
Fixed formatting issues with error messages in SHCoeffs.
Removed print statements from the fortran code in BAtoHilm and BAtoHilmRohH that served no purpose.
Fixed a bug in the argument order of the python wrappers of CilmPlusRhoDH and BAtoHilmRhoDH.
Fixed the makefile to remove the dist directory during clean.
Fixed a bug in the python routine cross_spectrum(), where the numpy arange function was incorrectly called.
Fixed theSHWindow plotting methods to work when the number of rows is equal to 1.
Conditional tests in the routine Wigner3j were reordered to avoid a division by zero.
Numpy’s auto-configuration is now used to detect the LAPACK libraries.
Many minor updates to the python documentation and unix man pages.

Citation:

M. A. Wieczorek, M. Meschede, E. Sales de Andrade, I. Oshchepkov, B. Xu, and A. Walker (2017). SHTOOLS: Version 4.1, Zenodo, doi:10.5281/zenodo.1067108

Version 4.0

This is a major update that fixes bugs, adds new functionality, and improves Python error handing. All users are requested to upgrade to 4.0.

Change log:

Instead of executing a Fortran STOP, which kills the Python kernel, the Fortran subroutines now return an exitstatus that allows Python to raise an exception. This technique does not work with the few Fortran functions that pyshtools calls, but these functions are relatively benign, and will soon be phased out for Python native functions.
The Fortran powerspectrum routines have been removed from pyshtools, and have been replaced with Python native routines spectrum and cross_spectrum. The Python routines allow to specify the normalization, whether the output should be power, energy or l2norm, and whether the spectrum is per degree, per coefficient, or per log bandwidth.
The method plot_spectrum2d() was added to the class SHCoeffs to plot the power as a function of degree and order.
All pyshtools modules have been converted into proper Python subpackages. The subpackage localizedpsectralanalysis has been merged into spectralanalysis, and the subpackage other has been renamed utils.
The Python class method SHCoeffs.expand() now can evaluate the function either on an SHGrid or for a list of latitude and longitude points. As part of this change, a new fortran function MakeGridPointC was created for complex coefficients.
The majority of the methods for the classes SHCoeffs, SHGrid and SHWindow have been rename for consistency (see documentation!). Also, the classes now give the option of reading or saving to files as numpy arrays.
Added new Python function read_icgen_gfc for reading ICGEM-format gravity coefficient files.
The operator pow was added to the class SHCoeffs.
All methods in the pyshtools classes now return copies by default, which can be modified by the optional argument copy.
Added pot as a mandatory return argument for the Python routine MakeGravGridDH.
Several minor modifications and bug fixes were made to the makefiles to improve compatibility and to allow the use of make -j.
The routines other.EigValSym, other.EigValVecSym, other.EigValVecSymTri, other.RandomGaussian, other.RandomN and other.PreGLQ were removed from pyshtools, as these can be found in other scipy packages.
The SHTOOLS routine DHaj was added to the pyshtools subpackage utils.
Python docstrings have been streamlined and standardized.
…plus, many minor changes and optimizations…

Citation:

M. A. Wieczorek, M. Meschede, I. Oshchepkov, E. Sales de Andrade, and heroxbd (2016). SHTOOLS: Version 4.0. Zenodo. doi:10.5281/zenodo.206114

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