Added a plotting function for struct. 2d vector fields

gstools/field/base.py

@@ -198,9 +198,22 @@ def plot(self, field="field", fig=None, ax=None):  # pragma: no cover
             Default: `None`
         """
         # just import if needed; matplotlib is not required by setup
-        from gstools.field.plot import plot_field
+        from gstools.field.plot import plot_field, plot_vec_field
+
+        # check if we have a vector field, this check should be sufficient
+        # for all but very edgy edge cases, which ate not going to be plotted
+        # anyway
+        if self.field.shape[0] == self.model.dim:
+            if self.model.dim == 2:
+                r = plot_vec_field(self, field, fig, ax)
+            else:
+                raise RuntimeError(
+                    "Streamflow plotting only supported for 2d case."
+                )
+        else:
+            r = plot_field(self, field, fig, ax)
 
-        return plot_field(self, field, fig, ax)
+        return r
 
     @property
     def mean(self):

gstools/field/plot.py

@@ -8,6 +8,7 @@
 
 .. autosummary::
    plot_field
+   plot_vec_field
 """
 # pylint: disable=C0103
 from __future__ import print_function, division, absolute_import
@@ -19,7 +20,7 @@
 from gstools.tools import pos2xyz
 from gstools.covmodel.plot import _get_fig_ax
 
-__all__ = ["plot_field"]
+__all__ = ["plot_field", "plot_vec_field"]
 
 
 # plotting routines #######################################################
@@ -207,3 +208,49 @@ def update(__):
     fig.colorbar(cont, cax=cax, ax=ax)
     fig.show()
     return ax
+
+def plot_vec_field(fld, field="field", fig=None, ax=None):  # pragma: no cover
+    """
+    Plot a spatial random vector field.
+
+    Parameters
+    ----------
+    fld : :class:`Field`
+        The given field class instance.
+    field : :class:`str`, optional
+        Field that should be plotted. Default: "field"
+    fig : :class:`Figure` or :any:`None`, optional
+        Figure to plot the axes on. If `None`, a new one will be created.
+        Default: `None`
+    ax : :class:`Axes` or :any:`None`, optional
+        Axes to plot on. If `None`, a new one will be added to the figure.
+        Default: `None`
+    """
+    if fld.mesh_type is not "structured":
+        raise RuntimeError(
+            "Only structured vector fields are supported"
+            + " for plotting. Please create one on a structured grid."
+        )
+    plot_field = getattr(fld, field)
+    assert not (fld.pos is None or plot_field is None)
+
+    norm = np.sqrt(plot_field[0, :].T ** 2 + plot_field[1, :].T ** 2)
+
+    fig, ax = _get_fig_ax(fig, ax)
+    title = "Field 2D " + fld.mesh_type + ": " + str(plot_field.shape)
+    x, y, __ = pos2xyz(fld.pos)
+
+    sp = plt.streamplot(
+        x,
+        y,
+        plot_field[0, :].T,
+        plot_field[1, :].T,
+        color=norm,
+        linewidth=norm / 2,
+    )
+    ax.set_xlabel("X")
+    ax.set_ylabel("Y")
+    ax.set_title(title)
+    fig.colorbar(sp.lines)
+    fig.show()
+    return ax