DOC/Projections "Polar": General improvements (#3634)

Author: yvonnefroehlich

examples/projections/nongeo/polar.py

@@ -2,50 +2,48 @@
 Polar
 =====
 
-Polar projections allow plotting polar coordinate data (e.g. angle
-:math:`\theta` and radius *r*).
+Polar projections allow plotting polar coordinate data (e.g. angle :math:`\theta` and
+radius *r*).
 
 The full syntax for polar projections is:
 
 **P**\ *width*\ [**+a**]\ [**+f**\ [**e**\|\ **p**\|\ *radius*]]\
 [**+r**\ *offset*][**+t**\ *origin*][**+z**\ [**p**\|\ *radius*]]
 
 Limits are set via the ``region`` parameter
-([*theta_min*, *theta_max*, *radius_min*, *radius_max*]). When using
-**P**\ *width* you have to give the *width* of the figure. The lower-case
-version **p** is similar to **P** but expects a *scale* instead of
-a width (**p**\ *scale*).
+([*theta_min*, *theta_max*, *radius_min*, *radius_max*]). When using **P**\ *width* you
+have to give the *width* of the figure. The lower-case version **p** is similar to **P**
+but expects a *scale* instead of a width (**p**\ *scale*).
 
 The following customizing modifiers are available:
 
-- **+a**: by default, :math:`\theta` refers to the angle that is equivalent to
-  a counterclockwise rotation with respect to the east direction (standard
-  definition); **+a** indicates that the input data are rotated clockwise
-  relative to the north direction (geographical azimuth angle).
+- **+a**: by default, :math:`\theta` refers to the angle that is equivalent to a
+  counterclockwise rotation with respect to the east direction (standard definition);
+  **+a** indicates that the input data are rotated clockwise relative to the north
+  direction (geographical azimuth angle).
 
-- **+r**\ *offset*: represents the offset of the r-axis. This modifier allows
-  you to offset the center of the circle from r=0.
+- **+r**\ *offset*: represents the offset of the r-axis. This modifier allows you to
+  offset the center of the circle from r=0.
 
 - **+t**\ *origin*: sets the angle corresponding to the east direction which is
-  equivalent to rotating the entire coordinate axis clockwise; if the **+a**
-  modifier is used, setting the angle corresponding to the north direction is
-  equivalent to rotating the entire coordinate axis counterclockwise.
+  equivalent to rotating the entire coordinate axis clockwise; if the **+a** modifier
+  is used, setting the angle corresponding to the north direction is equivalent to
+  rotating the entire coordinate axis counterclockwise.
 
 - **+f**: reverses the radial direction.
 
-  - Append **e** to indicate that the r-axis is an elevation angle, and the
-    range of the r-axis should be between 0° and 90°.
+  - Append **e** to indicate that the r-axis is an elevation angle, and the range of the
+    r-axis should be between 0° and 90°.
   - Appending **p** sets the current Earth radius (determined by
-    :gmt-term:`PROJ_ELLIPSOID`)
-    to the maximum value of the r-axis when the r-axis is reversed.
+    :gmt-term:`PROJ_ELLIPSOID`) to the maximum value of the r-axis when the r-axis is
+    reversed.
   - Append *radius* to set the maximum value of the r-axis.
 
-- **+z**: indicates that the r-axis is marked as depth instead of radius (e.g.
+- **+z**: indicates that the r-axis is marked as depth instead of radius (e.g.,
   *r = radius - z*).
 
   - Append **p** to set radius to the current Earth radius.
   - Append *radius* to set the value of the radius.
-
 """
 
 # %%
@@ -56,100 +54,94 @@
 pygmt.config(FONT_TITLE="14p,Courier,black", FORMAT_GEO_MAP="+D")
 
 # ============
-# top left
+# Top left
 fig.basemap(
-    # set map limits to theta_min = 0, theta_max = 360, radius_min = 0,
-    # radius_max = 1
+    # Set map limits to theta_min = 0, theta_max = 360, radius_min = 0, radius_max = 1
     region=[0, 360, 0, 1],
-    # set map width to 5 cm
+    # Set map width to 5 cm
     projection="P5c",
-    # set the frame and title; @^ allows for a line break within the title
+    # Set the frame and title; @^ allows for a line break within the title
     frame=["xa45f", "+gbisque+tprojection='P5c' @^ region=[0, 360, 0, 1]"],
 )
 
-fig.shift_origin(xshift="8c")
+fig.shift_origin(xshift="w+3c")
 
 # ============
-# top middle
+# Top middle
 fig.basemap(
-    # set map limits to theta_min = 0, theta_max = 360, radius_min = 0,
-    # radius_max = 1
+    # Set map limits to theta_min = 0, theta_max = 360, radius_min = 0, radius_max = 1
     region=[0, 360, 0, 1],
-    # set map width to 5 cm and interpret input data as geographic azimuth
-    # instead of standard angle
+    # Set map width to 5 cm and interpret input data as geographic azimuth instead of
+    # standard angle
     projection="P5c+a",
-    # set the frame and title; @^ allows for a line break within the title
+    # Set the frame and title; @^ allows for a line break within the title
     frame=["xa45f", "+gbisque+tprojection='P5c+a' @^ region=[0, 360, 0, 1]"],
 )
 
-fig.shift_origin(xshift="8c")
+fig.shift_origin(xshift="w+3c")
 
 # ============
-# top right
+# Top right
 fig.basemap(
-    # set map limits to theta_min = 0, theta_max = 90, radius_min = 0,
-    # radius_max = 1
+    # Set map limits to theta_min = 0, theta_max = 90, radius_min = 0, radius_max = 1
     region=[0, 90, 0, 1],
-    # set map width to 5 cm and interpret input data as geographic azimuth
-    # instead of standard angle
+    # Set map width to 5 cm and interpret input data as geographic azimuth instead of
+    # standard angle
     projection="P5c+a",
-    # set the frame and title; @^ allows for a line break within the title
+    # Set the frame and title; @^ allows for a line break within the title
     frame=["xa45f", "ya0.2", "WNe+gbisque+tprojection='P5c+a' @^ region=[0, 90, 0, 1]"],
 )
 
-fig.shift_origin(xshift="-16c", yshift="-7c")
+fig.shift_origin(xshift="-2w-6c", yshift="-h-2c")
 
 # ============
-# bottom left
+# Bottom left
 fig.basemap(
-    # set map limits to theta_min = 0, theta_max = 90, radius_min = 0,
-    # radius_max = 1
+    # Set map limits to theta_min = 0, theta_max = 90, radius_min = 0, radius_max = 1
     region=[0, 90, 0, 1],
-    # set map width to 5 cm and interpret input data as geographic azimuth
-    # instead of standard angle, rotate coordinate system counterclockwise by
-    # 45 degrees
+    # Set map width to 5 cm and interpret input data as geographic azimuth instead of
+    # standard angle, rotate coordinate system counterclockwise by 45 degrees
     projection="P5c+a+t45",
-    # set the frame and title; @^ allows for a line break within the title
+    # Set the frame and title; @^ allows for a line break within the title
     frame=[
         "xa30f",
         "ya0.2",
         "WNe+gbisque+tprojection='P5c+a+t45' @^ region=[0, 90, 0, 1]",
     ],
 )
 
-fig.shift_origin(xshift="8c", yshift="1.3c")
+fig.shift_origin(xshift="w+3c", yshift="1.3c")
 
 # ============
-# bottom middle
+# Bottom middle
 fig.basemap(
-    # set map limits to theta_min = 0, theta_max = 90, radius_min = 3480,
+    # Set map limits to theta_min = 0, theta_max = 90, radius_min = 3480,
     # radius_max = 6371 (Earth's radius)
     region=[0, 90, 3480, 6371],
-    # set map width to 5 cm and interpret input data as geographic azimuth
-    # instead of standard angle, rotate coordinate system counterclockwise by
-    # 45 degrees
+    # Set map width to 5 cm and interpret input data as geographic azimuth instead of
+    # standard angle, rotate coordinate system counterclockwise by 45 degrees
     projection="P5c+a+t45",
-    # set the frame, and title; @^ allows for a line break within the title
+    # Set the frame, and title; @^ allows for a line break within the title
     frame=[
         "xa30f",
         "ya",
         "WNse+gbisque+tprojection='P5c+a+t45' @^ region=[0, 90, 3480, 6371]",
     ],
 )
 
-fig.shift_origin(xshift="8c")
+fig.shift_origin(xshift="w+3c")
 
 # ============
-# bottom right
+# Bottom right
 fig.basemap(
-    # set map limits to theta_min = 0, theta_max = 90, radius_min = 3480,
+    # Set map limits to theta_min = 0, theta_max = 90, radius_min = 3480,
     # radius_max = 6371 (Earth's radius)
     region=[0, 90, 3480, 6371],
-    # set map width to 5 cm and interpret input data as geographic azimuth
-    # instead of standard angle, rotate coordinate system counterclockwise by
-    # 45 degrees, r-axis is marked as depth
+    # Set map width to 5 cm and interpret input data as geographic azimuth instead of
+    # standard angle, rotate coordinate system counterclockwise by 45 degrees, r-axis
+    # is marked as depth
     projection="P5c+a+t45+z",
-    # set the frame, and title; @^ allows for a line break within the title
+    # Set the frame, and title; @^ allows for a line break within the title
     frame=[
         "xa30f",
         "ya",