From f97c3a462a0d65e10da7707a71c9cc991457759a Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Sun, 29 Sep 2024 17:57:28 +0800
Subject: [PATCH] Figure.plot & Figure.plot3d: Move common codes into
 _common.py (#3461)

---
 pygmt/src/_common.py | 41 +++++++++++++++++++++++++++++++++++++++++
 pygmt/src/plot.py    | 21 ++++-----------------
 pygmt/src/plot3d.py  | 19 ++++---------------
 3 files changed, 49 insertions(+), 32 deletions(-)
 create mode 100644 pygmt/src/_common.py

diff --git a/pygmt/src/_common.py b/pygmt/src/_common.py
new file mode 100644
index 00000000000..96ae9791b71
--- /dev/null
+++ b/pygmt/src/_common.py
@@ -0,0 +1,41 @@
+"""
+Common functions used in multiple PyGMT functions/methods.
+"""
+
+from pathlib import Path
+from typing import Any
+
+from pygmt.src.which import which
+
+
+def _data_geometry_is_point(data: Any, kind: str) -> bool:
+    """
+    Check if the geometry of the input data is Point or MultiPoint.
+
+    The inptu data can be a GeoJSON object or a OGR_GMT file.
+
+    This function is used in ``Figure.plot`` and ``Figure.plot3d``.
+
+    Parameters
+    ----------
+    data
+        The data being plotted.
+    kind
+        The data kind.
+
+    Returns
+    -------
+    bool
+        ``True`` if the geometry is Point/MultiPoint, ``False`` otherwise.
+    """
+    if kind == "geojson" and data.geom_type.isin(["Point", "MultiPoint"]).all():
+        return True
+    if kind == "file" and str(data).endswith(".gmt"):  # OGR_GMT file
+        try:
+            with Path(which(data)).open(encoding="utf-8") as file:
+                line = file.readline()
+            if "@GMULTIPOINT" in line or "@GPOINT" in line:
+                return True
+        except FileNotFoundError:
+            pass
+    return False
diff --git a/pygmt/src/plot.py b/pygmt/src/plot.py
index e66f08438e5..61db357bfde 100644
--- a/pygmt/src/plot.py
+++ b/pygmt/src/plot.py
@@ -2,8 +2,6 @@
 plot - Plot in two dimensions.
 """
 
-from pathlib import Path
-
 from pygmt.clib import Session
 from pygmt.exceptions import GMTInvalidInput
 from pygmt.helpers import (
@@ -14,7 +12,7 @@
     kwargs_to_strings,
     use_alias,
 )
-from pygmt.src.which import which
+from pygmt.src._common import _data_geometry_is_point
 
 
 @fmt_docstring
@@ -50,9 +48,7 @@
     w="wrap",
 )
 @kwargs_to_strings(R="sequence", c="sequence_comma", i="sequence_comma", p="sequence")
-def plot(  # noqa: PLR0912
-    self, data=None, x=None, y=None, size=None, direction=None, **kwargs
-):
+def plot(self, data=None, x=None, y=None, size=None, direction=None, **kwargs):
     r"""
     Plot lines, polygons, and symbols in 2-D.
 
@@ -242,17 +238,8 @@ def plot(  # noqa: PLR0912
                 raise GMTInvalidInput(f"'{name}' can't be 1-D array if 'data' is used.")
 
     # Set the default style if data has a geometry of Point or MultiPoint
-    if kwargs.get("S") is None:
-        if kind == "geojson" and data.geom_type.isin(["Point", "MultiPoint"]).all():
-            kwargs["S"] = "s0.2c"
-        elif kind == "file" and str(data).endswith(".gmt"):  # OGR_GMT file
-            try:
-                with Path(which(data)).open(encoding="utf-8") as file:
-                    line = file.readline()
-                if "@GMULTIPOINT" in line or "@GPOINT" in line:
-                    kwargs["S"] = "s0.2c"
-            except FileNotFoundError:
-                pass
+    if kwargs.get("S") is None and _data_geometry_is_point(data, kind):
+        kwargs["S"] = "s0.2c"
 
     with Session() as lib:
         with lib.virtualfile_in(
diff --git a/pygmt/src/plot3d.py b/pygmt/src/plot3d.py
index c86e5e259f1..7c7a78f2ab3 100644
--- a/pygmt/src/plot3d.py
+++ b/pygmt/src/plot3d.py
@@ -2,8 +2,6 @@
 plot3d - Plot in three dimensions.
 """
 
-from pathlib import Path
-
 from pygmt.clib import Session
 from pygmt.exceptions import GMTInvalidInput
 from pygmt.helpers import (
@@ -14,7 +12,7 @@
     kwargs_to_strings,
     use_alias,
 )
-from pygmt.src.which import which
+from pygmt.src._common import _data_geometry_is_point
 
 
 @fmt_docstring
@@ -51,7 +49,7 @@
     w="wrap",
 )
 @kwargs_to_strings(R="sequence", c="sequence_comma", i="sequence_comma", p="sequence")
-def plot3d(  # noqa: PLR0912
+def plot3d(
     self, data=None, x=None, y=None, z=None, size=None, direction=None, **kwargs
 ):
     r"""
@@ -218,17 +216,8 @@ def plot3d(  # noqa: PLR0912
                 raise GMTInvalidInput(f"'{name}' can't be 1-D array if 'data' is used.")
 
     # Set the default style if data has a geometry of Point or MultiPoint
-    if kwargs.get("S") is None:
-        if kind == "geojson" and data.geom_type.isin(["Point", "MultiPoint"]).all():
-            kwargs["S"] = "u0.2c"
-        elif kind == "file" and str(data).endswith(".gmt"):  # OGR_GMT file
-            try:
-                with Path(which(data)).open(encoding="utf-8") as file:
-                    line = file.readline()
-                if "@GMULTIPOINT" in line or "@GPOINT" in line:
-                    kwargs["S"] = "u0.2c"
-            except FileNotFoundError:
-                pass
+    if kwargs.get("S") is None and _data_geometry_is_point(data, kind):
+        kwargs["S"] = "u0.2c"
 
     with Session() as lib:
         with lib.virtualfile_in(