Figure.meca: Fix beachball offsetting with dict/pandas inputs

Author: seisman

pygmt/src/meca.py

@@ -273,9 +273,9 @@ def meca(
         if depth is not None:
             spec["depth"] = np.atleast_1d(depth)
         if plot_longitude is not None:  # must be in string type
-            spec["plot_longitude"] = np.atleast_1d(plot_longitude).astype(str)
+            spec["plot_longitude"] = np.atleast_1d(plot_longitude)
         if plot_latitude is not None:  # must be in string type
-            spec["plot_latitude"] = np.atleast_1d(plot_latitude).astype(str)
+            spec["plot_latitude"] = np.atleast_1d(plot_latitude)
         if event_name is not None:
             spec["event_name"] = np.atleast_1d(event_name).astype(str)
 
@@ -293,9 +293,13 @@ def meca(
         newcols = ["longitude", "latitude", "depth"] + param_conventions[convention]
         if "plot_longitude" in spec.columns and "plot_latitude" in spec.columns:
             newcols += ["plot_longitude", "plot_latitude"]
+            spec[["plot_longitude", "plot_latitude"]] = spec[
+                ["plot_longitude", "plot_latitude"]
+            ].astype(str)
             kwargs["A"] = True
         if "event_name" in spec.columns:
             newcols += ["event_name"]
+            spec["event_name"] = spec["event_name"].astype(str)
         # reorder columns in DataFrame
         spec = spec.reindex(newcols, axis=1)
     elif isinstance(spec, np.ndarray) and spec.ndim == 1:

pygmt/tests/test_meca.py

@@ -253,6 +253,33 @@ def test_meca_dict_offset():
     return fig
 
 
+@pytest.mark.mpl_image_compare(filename="test_meca_dict_offset.png")
+def test_meca_dict_offset_in_dict():
+    """
+    Test offsetting beachballs for a dict input with offset parameters in the
+    dict.
+    See https://github.com/GenericMappingTools/pygmt/issues/2016.
+    """
+    fig = Figure()
+    focal_mechanism = dict(
+        strike=330,
+        dip=30,
+        rake=90,
+        magnitude=3,
+        plot_longitude=-124.5,
+        plot_latitude=47.5,
+    )
+    fig.basemap(region=[-125, -122, 47, 49], projection="M6c", frame=True)
+    fig.meca(
+        spec=focal_mechanism,
+        scale="1c",
+        longitude=-124,
+        latitude=48,
+        depth=12.0,
+    )
+    return fig
+
+
 @pytest.mark.mpl_image_compare
 def test_meca_dict_eventname():
     """