## 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.1345510

## 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