Wrap ternary

doc/api/index.rst

@@ -47,6 +47,7 @@ Plotting tabular data
     Figure.plot
     Figure.plot3d
     Figure.rose
+    Figure.ternary
     Figure.velo
     Figure.wiggle
 

pygmt/figure.py

@@ -442,6 +442,7 @@ def _repr_html_(self):
         set_panel,
         solar,
         subplot,
+        ternary,
         text,
         velo,
         wiggle,

pygmt/src/__init__.py

@@ -45,6 +45,7 @@
 from pygmt.src.sphinterpolate import sphinterpolate
 from pygmt.src.subplot import set_panel, subplot
 from pygmt.src.surface import surface
+from pygmt.src.ternary import ternary
 from pygmt.src.text import text_ as text  # "text" is an argument within "text_"
 from pygmt.src.velo import velo
 from pygmt.src.which import which

pygmt/src/ternary.py

@@ -0,0 +1,59 @@
+"""
+ternary - Plot data on ternary diagrams.
+"""
+from pygmt.clib import Session
+from pygmt.helpers import build_arg_string, fmt_docstring, kwargs_to_strings, use_alias
+
+
+@fmt_docstring
+@use_alias(
+    B="frame",
+    C="cmap",
+    F="center",
+    G="fill",
+    JX="projection",
+    R="region",
+    S="style",
+    U="timestamp",
+    V="verbose",
+    W="pen",
+    X="xshift",
+    Y="yshift",
+    p="perspective",
+    t="transparency",
+)
+@kwargs_to_strings(R="sequence", T="sequence", c="sequence_comma", p="sequence")
+def ternary(self, table, **kwargs):
+    r"""
+    Plots a histogram, and can read data from a file or
+    list, array, or dataframe.
+
+    Full option list at :gmt-docs:`histogram.html`
+
+    {aliases}
+
+    Parameters
+    ----------
+    table : str or list or {table-like}
+        Pass in either a file name to an ASCII data table, a Python list, a 2D
+        {table-classes}.
+    {J}
+    {R}
+    {CPT}
+    {G}
+    style : str
+        Plot symbols (including vectors, pie slices, fronts, decorated or
+        quoted lines).
+    {W}
+    {XY}
+    {U}
+    {V}
+    {p}
+    {t}
+    """
+    kwargs = self._preprocess(**kwargs)  # pylint: disable=protected-access
+    with Session() as lib:
+        file_context = lib.virtualfile_from_data(check_kind="vector", data=table)
+        with file_context as infile:
+            arg_str = " ".join([infile, build_arg_string(kwargs)])
+            lib.call_module("ternary", arg_str)

pygmt/tests/baseline/test_ternary.png.dvc

@@ -0,0 +1,4 @@
+outs:
+- md5: 9f6b57e9dd82aa24a8a013176ba8fb1d
+  size: 128744
+  path: test_ternary.png

pygmt/tests/test_ternary.py

@@ -0,0 +1,22 @@
+"""
+Tests ternary.
+"""
+import pytest
+from pygmt import Figure
+
+
+@pytest.mark.mpl_image_compare
+def test_ternary():
+    """
+    Test plotting a ternary chart.
+    """
+    fig = Figure()
+    fig.ternary(
+        table="@ternary.txt",
+        region="0/100/0/100/0/100",
+        cmap="red,orange,yellow,green,blue,violet",
+        projection="6i",
+        frame=["bafg+lAir", "cafg+lLimestone", "aafg+lWater"],
+        style="c0.1c",
+    )
+    return fig