Wrap docstrings to 79 chars and check with flake8 (#384)

Jupyter, IPython, and other IDEs don't usually render the rst in the
docstrings and just show them literally. The problem is that many of
these break lines at 79 characters. So docstrings with more characters
look terrible in these settings and sometimes almost unreadable. Wrap
all docstrings to 79 characters instead of Black's 88. Set
`max-doc-length=79` to make flake8 check if any docstring exceeds it.
The setting checks comments as well and we found no way of disabling
that. So we'll format comments to 79 characters for consistency as well.
Minor modifications to the first line of some docstrings was required to
make them fit into a single line. Also made minor modifications on some
doctests to wrap to 79 characters.

.gitignore

@@ -11,6 +11,7 @@ MANIFEST
 .pytest_cache/
 .ipynb_checkpoints/
 .vscode/
+tmp-test-dir-with-unique-name/
 build/
 dist/
 doc/_build

CONTRIBUTING.md

@@ -269,6 +269,17 @@ make check # Runs flake8 and black (in check mode)
 make lint # Runs pylint, which is a bit slower
 ```
 
+#### Docstrings
+
+**All docstrings** should follow the
+[numpy style guide](https://numpydoc.readthedocs.io/en/latest/format.html#docstring-standard).
+All functions/classes/methods should have docstrings with a full description of all
+arguments and return values.
+
+While the maximum line length for code is automatically set by *Black*, docstrings
+must be formatted manually. To play nicely with Jupyter and IPython, **keep docstrings
+limited to 79 characters** per line.
+
 ### Testing your code
 
 Automated testing helps ensure that our code is as free of bugs as it can be.
@@ -360,7 +371,7 @@ Sphinx will create a link to the automatically generated page for that
 function/class/module.
 
 **All docstrings** should follow the
-[numpy style guide](https://github.com/numpy/numpy/blob/master/doc/HOWTO_DOCUMENT.rst.txt).
+[numpy style guide](https://numpydoc.readthedocs.io/en/latest/format.html).
 All functions/classes/methods should have docstrings with a full description of all
 arguments and return values.
 
@@ -379,7 +390,7 @@ Some things that will increase the chance that your pull request is accepted qui
  *reason* behind non-obvious things.
 * Include an example of new features in the gallery or tutorials.
 * Follow the [PEP8](https://pep8.org) style guide for code and the
- [numpy guide](https://github.com/numpy/numpy/blob/master/doc/HOWTO_DOCUMENT.rst.txt)
+ [numpy guide](https://numpydoc.readthedocs.io/en/latest/format.html)
  for documentation.
 
 Pull requests will automatically have tests run by TravisCI.

pygmt/__init__.py

@@ -2,10 +2,10 @@
 #
 # The main API for PyGMT.
 #
-# All of PyGMT is operated on a "modern mode session" (new to GMT6). When you import the
-# pygmt library, a new session will be started automatically. The session will be
-# closed when the current Python process terminates. Thus, the Python API does not
-# expose the `gmt begin` and `gmt end` commands.
+# All of PyGMT is operated on a "modern mode session" (new to GMT6). When you
+# import the pygmt library, a new session will be started automatically. The
+# session will be closed when the current Python process terminates. Thus, the
+# Python API does not expose the `gmt begin` and `gmt end` commands.
 
 import atexit as _atexit
 
@@ -34,8 +34,8 @@ def print_clib_info():
  """
  Print information about the GMT shared library that we can find.
 
- Includes the GMT version, default values for parameters, the path to the ``libgmt``
- shared library, and GMT directories.
+ Includes the GMT version, default values for parameters, the path to the
+ ``libgmt`` shared library, and GMT directories.
  """
  from .clib import Session
 

pygmt/base_plotting.py

@@ -36,8 +36,8 @@ def _preprocess(self, **kwargs): # pylint: disable=no-self-use
  insert special arguments into the kwargs or make any actions that are
  required before ``call_module``.
 
- For example, the :class:`pygmt.Figure` needs this to tell the GMT modules
- to plot to a specific figure.
+ For example, the :class:`pygmt.Figure` needs this to tell the GMT
+ modules to plot to a specific figure.
 
  This is a dummy method that does nothing.
 
@@ -147,63 +147,61 @@ def colorbar(self, **kwargs):
  """
  Plot a gray or color scale-bar on maps.
 
- Both horizontal and vertical scales are supported. For CPTs with gradational
- colors (i.e., the lower and upper boundary of an interval have different colors)
- we will interpolate to give a continuous scale. Variations in intensity due to
- shading/illumination may be displayed by setting the option -I. Colors may be
- spaced according to a linear scale, all be equal size, or by providing a file
- with individual tile widths.
+ Both horizontal and vertical scales are supported. For CPTs with
+ gradational colors (i.e., the lower and upper boundary of an interval
+ have different colors) we will interpolate to give a continuous scale.
+ Variations in intensity due to shading/illumination may be displayed by
+ setting the option -I. Colors may be spaced according to a linear
+ scale, all be equal size, or by providing a file with individual tile
+ widths.
 
  Full option list at :gmt-docs:`colorbar.html`
 
  Parameters
  ----------
  position (D) : str
- ``[g|j|J|n|x]refpoint[+wlength[/width]][+e[b|f][length]][+h|v][+jjustify]
- [+m[a|c|l|u]][+n[txt]][+odx[/dy]]``.
- Defines the reference point on the map for the color scale using one of four
- coordinate systems:
- (1) Use -Dg for map (user) coordinates,
- (2) use -Dj or -DJ for setting refpoint via a 2-char justification code that
- refers to the (invisible) map domain rectangle,
- (3) use -Dn for normalized (0-1) coordinates, or
- (4) use -Dx for plot coordinates (inches, cm, etc.).\
- All but -Dx requires both -R and -J to be specified.
- Append +w followed by the length and width of the color bar.
- If width is not specified then it is set to 4% of the given length.
- Give a negative length to reverse the scale bar.
- Append +h to get a horizontal scale [Default is vertical (+v)].
- By default, the anchor point on the scale is assumed to be the bottom left
- corner (BL), but this can be changed by appending +j followed by a 2-char
- justification code justify.
+ ``[g|j|J|n|x]refpoint[+wlength[/width]][+e[b|f][length]][+h|v]
+ [+jjustify][+m[a|c|l|u]][+n[txt]][+odx[/dy]]``. Defines the
+ reference point on the map for the color scale using one of four
+ coordinate systems: (1) Use -Dg for map (user) coordinates, (2) use
+ -Dj or -DJ for setting refpoint via a 2-char justification code
+ that refers to the (invisible) map domain rectangle, (3) use -Dn
+ for normalized (0-1) coordinates, or (4) use -Dx for plot
+ coordinates (inches, cm, etc.). All but -Dx requires both -R and
+ -J to be specified. Append +w followed by the length and width of
+ the color bar. If width is not specified then it is set to 4% of
+ the given length. Give a negative length to reverse the scale bar.
+ Append +h to get a horizontal scale [Default is vertical (+v)]. By
+ default, the anchor point on the scale is assumed to be the bottom
+ left corner (BL), but this can be changed by appending +j followed
+ by a 2-char justification code justify.
 
  box (F) : bool or str
- ``[+cclearances][+gfill][+i[[gap/]pen]][+p[pen]][+r[radius]][+s[[dx/dy/]
- [shade]]]``.
- If set to True, draws a rectangular border around the color scale.
- Alternatively, specify a different pen with +ppen.
- Add +gfill to fill the scale panel [no fill].
+ ``[+cclearances][+gfill][+i[[gap/]pen]][+p[pen]][+r[radius]]
+ [+s[[dx/dy/][shade]]]``. If set to True, draws a rectangular
+ border around the color scale. Alternatively, specify a different
+ pen with +ppen. Add +gfill to fill the scale panel [no fill].
  Append +cclearance where clearance is either gap, xgap/ygap, or
- lgap/rgap/bgap/tgap where these items are uniform, separate in x- and
- y-direction, or individual side spacings between scale and border.
- Append +i to draw a secondary, inner border as well. We use a uniform gap
- between borders of 2p and the MAP_DEFAULTS_PEN unless other values are
- specified.
- Append +r to draw rounded rectangular borders instead, with a 6p corner
- radius. You can override this radius by appending another value.
- Finally, append +s to draw an offset background shaded region. Here, dx/dy
- indicates the shift relative to the foreground frame [4p/-4p] and shade sets
- the fill style to use for shading [gray50].
+ lgap/rgap/bgap/tgap where these items are uniform, separate in x-
+ and y-direction, or individual side spacings between scale and
+ border. Append +i to draw a secondary, inner border as well. We use
+ a uniform gap between borders of 2p and the MAP_DEFAULTS_PEN unless
+ other values are specified. Append +r to draw rounded rectangular
+ borders instead, with a 6p corner radius. You can override this
+ radius by appending another value. Finally, append +s to draw an
+ offset background shaded region. Here, dx/dy indicates the shift
+ relative to the foreground frame [4p/-4p] and shade sets the fill
+ style to use for shading [gray50].
 
  truncate (G) : list or str
- ``zlo/zhi``
- Truncate the incoming CPT so that the lowest and highest z-levels are to zlo
- and zhi. If one of these equal NaN then we leave that end of the CPT alone.
- The truncation takes place before the plotting.
+ ``zlo/zhi`` Truncate the incoming CPT so that the lowest and
+ highest z-levels are to zlo and zhi. If one of these equal NaN then
+ we leave that end of the CPT alone. The truncation takes place
+ before the plotting.
 
  scale (W) : float
- Multiply all z-values in the CPT by the provided scale. By default the CPT
- is used as is.
+ Multiply all z-values in the CPT by the provided scale. By default
+ the CPT is used as is.
 
  {aliases}
  """
@@ -362,7 +360,8 @@ def plot(self, x=None, y=None, data=None, sizes=None, direction=None, **kwargs):
  Parameters
  ----------
  x, y : float or 1d arrays
- The x and y coordinates, or arrays of x and y coordinates of the data points
+ The x and y coordinates, or arrays of x and y coordinates of the
+ data points
  data : str or 2d array
  Either a data file name or a 2d numpy array with the tabular data.
  Use option *columns* (i) to choose which columns are x, y, color,
@@ -594,7 +593,8 @@ def image(self, imagefile, **kwargs):
  """
  Place images or EPS files on maps.
 
- Reads an Encapsulated PostScript file or a raster image file and plots it on a map.
+ Reads an Encapsulated PostScript file or a raster image file and plots
+ it on a map.
 
  Full option list at :gmt-docs:`image.html`
 
@@ -605,12 +605,13 @@ def image(self, imagefile, **kwargs):
  {J}
  {R}
  D: str
- ``'[g|j|J|n|x]refpoint+rdpi+w[-]width[/height][+jjustify][+nnx[/ny]][+odx[/dy]]'``
- Sets reference point on the map for the image.
+ ``'[g|j|J|n|x]refpoint+rdpi+w[-]width[/height][+jjustify]
+ [+nnx[/ny]][+odx[/dy]]'`` Sets reference point on the map for the
+ image.
  F : bool or str
- ``'[+cclearances][+gfill][+i[[gap/]pen]][+p[pen]][+r[radius]][+s[[dx/dy/][shade]]]'``
- Without further options, draws a rectangular border around the
- image using **MAP_FRAME_PEN**.
+ ``'[+cclearances][+gfill][+i[[gap/]pen]][+p[pen]][+r[radius]]
+ [+s[[dx/dy/][shade]]]'`` Without further options, draws a
+ rectangular border around the image using **MAP_FRAME_PEN**.
  M : bool
  Convert color image to monochrome grayshades using the (television)
  YIQ-transformation.
@@ -627,11 +628,11 @@ def legend(self, spec=None, position="JTR+jTR+o0.2c", box="+gwhite+p1p", **kwarg
  """
  Plot legends on maps.
 
- Makes legends that can be overlaid on maps. Reads specific legend-related
- information from an input file, or automatically creates legend entries from
- plotted symbols that have labels. Unless otherwise noted, annotations will be
- made using the primary annotation font and size in effect
- (i.e., FONT_ANNOT_PRIMARY).
+ Makes legends that can be overlaid on maps. Reads specific
+ legend-related information from an input file, or automatically creates
+ legend entries from plotted symbols that have labels. Unless otherwise
+ noted, annotations will be made using the primary annotation font and
+ size in effect (i.e., FONT_ANNOT_PRIMARY).
 
  Full option list at :gmt-docs:`legend.html`
 
@@ -641,19 +642,21 @@ def legend(self, spec=None, position="JTR+jTR+o0.2c", box="+gwhite+p1p", **kwarg
  ----------
  spec : None or str
  Either None (default) for using the automatically generated legend
- specification file, or a filename pointing to the legend specification file.
+ specification file, or a filename pointing to the legend
+ specification file.
  {J}
  {R}
  position (D) : str
- ``'[g|j|J|n|x]refpoint+wwidth[/height][+jjustify][+lspacing][+odx[/dy]]'``
- Defines the reference point on the map for the legend. By default, uses
- 'JTR+jTR+o0.2c' which places the legend at the top-right corner inside
- the map frame, with a 0.2 cm offset.
+ ``'[g|j|J|n|x]refpoint+wwidth[/height][+jjustify][+lspacing]
+ [+odx[/dy]]'`` Defines the reference point on the map for the
+ legend. By default, uses 'JTR+jTR+o0.2c' which places the legend at
+ the top-right corner inside the map frame, with a 0.2 cm offset.
  box (F) : bool or str
- ``'[+cclearances][+gfill][+i[[gap/]pen]][+p[pen]][+r[radius]][+s[[dx/dy/][shade]]]'``
- Without further options, draws a rectangular border around the
- legend using **MAP_FRAME_PEN**. By default, uses '+gwhite+p1p' which draws
- a box around the legend using a 1 point black pen and adds a white background.
+ ``'[+cclearances][+gfill][+i[[gap/]pen]][+p[pen]][+r[radius]]
+ [+s[[dx/dy/][shade]]]'`` Without further options, draws a
+ rectangular border around the legend using **MAP_FRAME_PEN**. By
+ default, uses '+gwhite+p1p' which draws a box around the legend
+ using a 1 point black pen and adds a white background.
  """
  kwargs = self._preprocess(**kwargs)
 
@@ -709,28 +712,30 @@ def text(
  Parameters
  ----------
  textfiles : str or list
- A text data file name, or a list of filenames containing 1 or more records
- with (x, y[, font, angle, justify], text).
+ A text data file name, or a list of filenames containing 1 or more
+ records with (x, y[, font, angle, justify], text).
  x, y : float or 1d arrays
- The x and y coordinates, or an array of x and y coordinates to plot the text
+ The x and y coordinates, or an array of x and y coordinates to plot
+ the text
  text : str or 1d array
  The text string, or an array of strings to plot on the figure
  angle: int/float or bool
- Set the angle measured in degrees counter-clockwise from horizontal. E.g. 30
- sets the text at 30 degrees. If no angle is given then the input textfile(s)
- must have this as a column.
+ Set the angle measured in degrees counter-clockwise from
+ horizontal. E.g. 30 sets the text at 30 degrees. If no angle is
+ given then the input textfile(s) must have this as a column.
  font : str or bool
- Set the font specification with format "size,font,color" where size is text
- size in points, font is the font to use, and color sets the font color. E.g.
- "12p,Helvetica-Bold,red" selects a 12p red Helvetica-Bold font. If no font
- info is given then the input textfile(s) must have this information in one
- of its columns.
+ Set the font specification with format "size,font,color" where size
+ is text size in points, font is the font to use, and color sets the
+ font color. E.g. "12p,Helvetica-Bold,red" selects a 12p red
+ Helvetica-Bold font. If no font info is given then the input
+ textfile(s) must have this information in one of its columns.
  justify: str or bool
- Set the alignment which refers to the part of the text string that will be
- mapped onto the (x,y) point. Choose a 2 character combination of L, C, R
- (for left, center, or right) and T, M, B for top, middle, or bottom. E.g.,
- BL for lower left. If no justification is given then the input textfile(s)
- must have this as a column.
+ Set the alignment which refers to the part of the text string that
+ will be mapped onto the (x,y) point. Choose a 2 character
+ combination of L, C, R (for left, center, or right) and T, M, B for
+ top, middle, or bottom. E.g., BL for lower left. If no
+ justification is given then the input textfile(s) must have this as
+ a column.
  {J}
  {R}
  """

pygmt/clib/__init__.py

@@ -2,7 +2,7 @@
 #
 # Low-level wrapper for the GMT C API.
 #
-# The pygmt.clib.Session class wraps the GMT C shared library (libgmt) with a pythonic
-# interface. Access to the C library is done through ctypes.
+# The pygmt.clib.Session class wraps the GMT C shared library (libgmt) with a
+# pythonic interface. Access to the C library is done through ctypes.
 
 from .session import Session

pygmt/clib/loading.py

@@ -1,8 +1,8 @@
 """
 Utility functions to load libgmt as ctypes.CDLL.
 
-The path to the shared library can be found automatically by ctypes or set through the
-GMT_LIBRARY_PATH environment variable.
+The path to the shared library can be found automatically by ctypes or set
+through the GMT_LIBRARY_PATH environment variable.
 """
 import os
 import sys
@@ -91,8 +91,8 @@ def clib_name(os_name=None, is_64bit=None):
  The operating system name as given by ``sys.platform``
  (the default if None).
  is_64bit : bool or None
- Whether or not the OS is 64bit. Only used if the OS is ``win32``. If None, will
- determine automatically.
+ Whether or not the OS is 64bit. Only used if the OS is ``win32``. If
+ None, will determine automatically.
 
  Returns
  -------