Figure.wiggle: Add parameters position/length/label/label_alignment for the scalebar position and properties (#4049)

Author: seisman

examples/gallery/lines/wiggle.py

@@ -2,17 +2,17 @@
 Wiggle along tracks
 ===================
 
-The :meth:`pygmt.Figure.wiggle` method can plot z = f(x,y) anomalies along
-tracks. ``x``, ``y``, ``z`` can be specified as 1-D arrays or within a
-specified file. The ``scale`` parameter can be used to set the scale of the
-anomaly in data/distance units. The positive and/or negative areas can be
-filled with color by setting the ``positive_fill`` and/or ``negative_fill``
-parameters.
+The :meth:`pygmt.Figure.wiggle` method can plot z = f(x,y) anomalies along tracks.
+``x``, ``y``, ``z`` can be specified as 1-D arrays or within a specified file. The
+``scale`` parameter can be used to set the scale of the anomaly in data/distance units.
+The positive and/or negative areas can be filled with color by setting the
+``positive_fill`` and/or ``negative_fill`` parameters.
 """
 
 # %%
 import numpy as np
 import pygmt
+from pygmt.params import Position
 
 # Create (x, y, z) triplets
 x = np.arange(-7, 7, 0.1)
@@ -25,18 +25,13 @@
     x=x,
     y=y,
     z=z,
-    # Set anomaly scale to 20 centimeters
-    scale="20c",
-    # Fill positive areas red
-    positive_fill="red",
-    # Fill negative areas gray
-    negative_fill="gray",
-    # Set the outline width to 1.0 point
-    pen="1.0p",
-    # Draw a blue track with a width of 0.5 points
-    track="0.5p,blue",
-    # Plot a vertical scale bar at Middle Right (MR). The bar length (+w)
-    # is 100 in data (z) units. Set the z unit label (+l) to "nT".
-    position="jMR+w100+lnT",
+    scale="20c",  # Set anomaly scale to 20 centimeters
+    positive_fill="red",  # Fill positive areas red
+    negative_fill="gray",  # Fill negative areas gray
+    pen="1.0p",  # Set the outline width to 1.0 point
+    track="0.5p,blue",  # Draw a blue track with a width of 0.5 points
+    position=Position("MR"),  # Plot a vertical scale bar at Middle Right (MR).
+    length=100,  # Bar length is 100 in data (z) units.
+    label="nT",  # Set the z unit label to "nT".
 )
 fig.show()

pygmt/src/wiggle.py

@@ -5,10 +5,12 @@
 from collections.abc import Sequence
 from typing import Literal
 
-from pygmt._typing import PathLike, TableLike
+from pygmt._typing import AnchorCode, PathLike, TableLike
 from pygmt.alias import Alias, AliasSystem
 from pygmt.clib import Session
 from pygmt.helpers import build_arg_list, deprecate_parameter, fmt_docstring, use_alias
+from pygmt.params import Position
+from pygmt.src._common import _parse_position
 
 
 def _parse_fills(positive_fill, negative_fill):
@@ -46,7 +48,6 @@ def _parse_fills(positive_fill, negative_fill):
     "fillnegative", "negative_fill", "v0.18.0", remove_version="v0.20.0"
 )
 @use_alias(
-    D="position",
     T="track",
     W="pen",
     Z="scale",
@@ -64,6 +65,10 @@ def wiggle(  # noqa: PLR0913
     x=None,
     y=None,
     z=None,
+    position: Position | Sequence[float | str] | AnchorCode | None = None,
+    length: float | str | None = None,
+    label: str | None = None,
+    label_alignment: Literal["left", "right"] | None = None,
     positive_fill=None,
     negative_fill=None,
     projection: str | None = None,
@@ -72,8 +77,8 @@ def wiggle(  # noqa: PLR0913
     verbose: Literal["quiet", "error", "warning", "timing", "info", "compat", "debug"]
     | bool = False,
     panel: int | Sequence[int] | bool = False,
-    transparency: float | None = None,
     perspective: float | Sequence[float] | str | bool = False,
+    transparency: float | None = None,
     incols: int | str | Sequence[int | str] | None = None,
     **kwargs,
 ):
@@ -89,6 +94,7 @@ def wiggle(  # noqa: PLR0913
 
     $aliases
        - B = frame
+       - D = **+w**: length, **+l**: label, **+a**: label_alignment
        - G = **+p**: positive_fill, **+n**: negative_fill
        - J = projection
        - R = region
@@ -107,29 +113,45 @@ def wiggle(  # noqa: PLR0913
         $table_classes.
         Use parameter ``incols`` to choose which columns are x, y, z,
         respectively.
-    $projection
-    $region
+
+    position
+        Position of the vertical scale on the plot. It can be specified in multiple
+        ways:
+
+        - A :class:`pygmt.params.Position` object to fully control the reference point,
+          anchor point, and offset.
+        - A sequence of two values representing the x- and y- coordinates in plot
+          coordinates, e.g., ``(1, 2)`` or ``("1c", "2c")``.
+        - A :doc:`2-character justification code </techref/justification_codes>` for a
+          position inside the plot, e.g., ``"TL"`` for Top Left corner inside the plot.
+
+        If not specified, defaults to the Bottom Left corner of the plot with a 0.2-cm
+        offset.
+    length
+        Length of the vertical scale bar in data (z) units.
+    label
+        Set the z unit label that is used in the scale label [Default is no unit].
+    label_alignment
+        Set the alignment of the scale label. Choose from ``"left"`` or ``"right"``
+        [Default is ``"left"``].
     scale : str or float
         Give anomaly scale in data-units/distance-unit. Append **c**, **i**,
         or **p** to indicate the distance unit (centimeters, inches, or
         points); if no unit is given we use the default unit that is
         controlled by :gmt-term:`PROJ_LENGTH_UNIT`.
-    $frame
-    position : str
-        [**g**\|\ **j**\|\ **J**\|\ **n**\|\ **x**]\ *refpoint*\
-        **+w**\ *length*\ [**+j**\ *justify*]\ [**+al**\|\ **r**]\
-        [**+o**\ *dx*\ [/*dy*]][**+l**\ [*label*]].
-        Define the reference point on the map for the vertical scale bar.
     positive_fill : str
         Set color or pattern for filling positive wiggles [Default is no fill].
     negative_fill : str
         Set color or pattern for filling negative wiggles [Default is no fill].
     track : str
         Draw track [Default is no track]. Append pen attributes to use
         [Default is ``"0.25p,black,solid"``].
-    $verbose
     pen : str
         Specify outline pen attributes [Default is no outline].
+    $projection
+    $region
+    $frame
+    $verbose
     $binary
     $panel
     $nodata
@@ -144,9 +166,26 @@ def wiggle(  # noqa: PLR0913
     """
     self._activate_figure()
 
+    position = _parse_position(
+        position,
+        kwdict={"length": length, "label": label, "label_alignment": label_alignment},
+        default=Position("BL", offset=0.2),  # Default to BL with 0.2-cm offset.
+    )
+
     _fills = _parse_fills(positive_fill, negative_fill)
 
     aliasdict = AliasSystem(
+        D=[
+            Alias(position, name="position"),
+            Alias(length, name="length", prefix="+w"),
+            Alias(
+                label_alignment,
+                name="label_alignment",
+                prefix="+a",
+                mapping={"left": "l", "right": "r"},
+            ),
+            Alias(label, name="label", prefix="+l"),
+        ],
         G=Alias(_fills, name="positive_fill/negative_fill"),
     ).add_common(
         B=frame,

pygmt/tests/baseline/test_wiggle_default_position.png.dvc

@@ -0,0 +1,5 @@
+outs:
+- md5: 362640b4554c7e5097340c578a672988
+  size: 16058
+  hash: md5
+  path: test_wiggle_default_position.png

pygmt/tests/test_wiggle.py

@@ -5,17 +5,73 @@
 import numpy as np
 import pytest
 from pygmt import Figure
+from pygmt.exceptions import GMTInvalidInput
+from pygmt.params import Position
 
 
-@pytest.mark.mpl_image_compare
-def test_wiggle():
+@pytest.fixture(scope="module", name="data")
+def fixture_xyz():
     """
-    Plot the z=f(x,y) anomalies along tracks.
+    Create sample (x, y, z) data for testing.
     """
     x = np.arange(-2, 2, 0.02)
     y = np.zeros(x.size)
     z = np.cos(2 * np.pi * x)
+    return (x, y, z)
+
+
+@pytest.mark.mpl_image_compare
+def test_wiggle(data):
+    """
+    Plot the z=f(x,y) anomalies along tracks.
+    """
+    x, y, z = data
+    fig = Figure()
+    fig.wiggle(
+        region=[-4, 4, -1, 1],
+        projection="X8c",
+        x=x,
+        y=y,
+        z=z,
+        scale="0.5c",
+        positive_fill="red",
+        negative_fill="gray",
+        pen="1.0p",
+        track="0.5p",
+        position=Position("MR"),
+        length=2,
+        label="nT",
+    )
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_wiggle_default_position(data):
+    """
+    Test that wiggle works when position is not provided.
+    """
+    x, y, z = data
+    fig = Figure()
+    fig.wiggle(
+        region=[-4, 4, -1, 1],
+        projection="X8c",
+        frame=True,
+        x=x,
+        y=y,
+        z=z,
+        pen="1p",
+        scale="0.5c",
+        length=1,
+    )
+    return fig
+
 
+@pytest.mark.mpl_image_compare(filename="test_wiggle.png")
+def test_wiggle_deprecated_position_syntax(data):
+    """
+    Test the deprecated position syntax for wiggle.
+    """
+    x, y, z = data
     fig = Figure()
     fig.wiggle(
         region=[-4, 4, -1, 1],
@@ -28,23 +84,20 @@ def test_wiggle():
         negative_fill="gray",
         pen="1.0p",
         track="0.5p",
-        position="jRM+w2+lnT",
+        position="jMR+w2+lnT",
     )
     return fig
 
 
 @pytest.mark.benchmark
 @pytest.mark.mpl_image_compare(filename="test_wiggle.png")
-def test_wiggle_data_incols():
+def test_wiggle_data_incols(data):
     """
     Make sure that incols parameter works with input data array.
     """
-
     # put data into numpy array and swap x and y columns
     # as the use of the 'incols' parameter will reverse this action
-    x = np.arange(-2, 2, 0.02)
-    y = np.zeros(x.size)
-    z = np.cos(2 * np.pi * x)
+    x, y, z = data
     data = np.array([y, x, z]).T
 
     fig = Figure()
@@ -58,6 +111,36 @@ def test_wiggle_data_incols():
         negative_fill="gray",
         pen="1.0p",
         track="0.5p",
-        position="jRM+w2+lnT",
+        position=Position("MR"),
+        length=2,
+        label="nT",
     )
     return fig
+
+
+def test_wiggle_mixed_syntax(data):
+    """
+    Test that an error is raised when mixing new and deprecated syntax in 'position'.
+    """
+    x, y, z = data
+    fig = Figure()
+    kwargs = {
+        "region": [-4, 4, -1, 1],
+        "projection": "X8c",
+        "x": x,
+        "y": y,
+        "z": z,
+        "scale": "0.5c",
+        "positive_fill": "red",
+        "negative_fill": "gray",
+        "pen": "1.0p",
+        "track": "0.5p",
+    }
+    with pytest.raises(GMTInvalidInput):
+        fig.wiggle(position="jMR+w2+lnT", length=2, **kwargs)
+
+    with pytest.raises(GMTInvalidInput):
+        fig.wiggle(position="jMR+w2+lnT", label="nT", **kwargs)
+
+    with pytest.raises(GMTInvalidInput):
+        fig.wiggle(position="jMR+w2+lnT", length_alignment="left", **kwargs)