[semver:patch] Fix density and lonlatbox in mapvector (#45)

Merge pull request #45 from psyplot/develop

.circleci/config.yml

 version: 2.1
 
 orbs:
-  psyplot: psyplot/psyplot-ci-orb@1.5.31
+  psyplot: psyplot/psyplot-ci-orb@1.5.32
   mattermost-plugin-notify: nathanaelhoun/mattermost-plugin-notify@1.2.0
 
 executors:

CHANGELOG.rst

+V1.4.2
+======
+Fix mapvector issue
+
+Fixed
+-----
+- This PR fixes an issue that arises when using ``density`` together with
+  ``lonlatbox``, see `#43 <https://github.com/psyplot/psy-maps/issues/43>`__
+  and `#44 <https://github.com/psyplot/psy-maps/pull/44>`__
+
 v1.4.1
 ======
 Fix projection issues

psy_maps/plotters.py

@@ -273,6 +273,20 @@ class ProjectionBase(Formatoption):
         #'vertical_perspective',  # not available for cartopy
         ]
 
+    def transform_lonlatbox(self, value):
+        """Transform a lon-lat-box to the specific projection"""
+        value = np.asarray(value)
+        transformed = self.projection.transform_points(
+            ccrs.PlateCarree(), value[:2], value[2:]
+        )[..., :2]
+        value[:2] = transformed[..., 0]
+        value[2:] = transformed[..., 1]
+        if value[0] == value[1] and isinstance(
+                self.projection, ccrs.PlateCarree
+            ):
+            value[1] += 360
+        return value
+
     @property
     def cf_projection(self):
         data = next(self.iter_data)
@@ -514,12 +528,17 @@ class Projection(ProjectionBase):
 
     dependencies = ['clon', 'clat']
 
-    connections = ['transform']
+    connections = ['transform', 'lonlatbox']
 
     def __init__(self, *args, **kwargs):
         super(Projection, self).__init__(*args, **kwargs)
         self.projection = None
 
+    @property
+    def lonlatbox_transformed(self):
+        """Transform the lonlatbox according to the projection"""
+        return self.transform_lonlatbox(self.lonlatbox.lonlatbox)
+
     def initialize_plot(self, value, clear=True):
         """Initialize the plot and set the projection for the axes
         """
@@ -715,15 +734,7 @@ class LonLatBox(BoxBase):
 
     @property
     def lonlatbox_transformed(self):
-        value = np.asarray(self.lonlatbox)
-        transformed = self.transform.projection.transform_points(
-            ccrs.PlateCarree(), value[:2], value[2:])[..., :2]
-        value[:2] = transformed[..., 0]
-        value[2:] = transformed[..., 1]
-        if value[0] == value[1] and isinstance(self.transform.projection,
-                                               ccrs.PlateCarree):
-            value[1] += 360
-        return value
+        return self.transform.transform_lonlatbox(self.lonlatbox)
 
     def data_dependent(self, data, set_data=True):
         if isinstance(data, InteractiveList):
@@ -1927,9 +1938,12 @@ class MapDensity(psyps.Density):
     --------------
     %(Density.possible_types)s"""
 
+    dependencies = psyps.Density.dependencies + ["projection"]
+
     def _set_quiver_density(self, value):
         if all(val == 1.0 for val in value):
             self.plot._kwargs.pop('regrid_shape', None)
+            self.plot._kwargs.pop('target_extent', None)
         elif self.decoder.is_unstructured(self.raw_data):
             warnings.warn("Quiver plot of unstructered data does not support "
                           "the density keyword!", RuntimeWarning)
@@ -1940,6 +1954,8 @@ class MapDensity(psyps.Density):
             shape = self.data.shape[-2:]
             value = map(int, [value[0]*shape[0], value[1]*shape[1]])
             self.plot._kwargs['regrid_shape'] = tuple(value)
+            lonlatbox = self.projection.lonlatbox_transformed
+            self.plot._kwargs["target_extent"] = lonlatbox
 
     def _unset_quiver_density(self):
         self.plot._kwargs.pop('regrid_shape', None)

tests/conftest.py

@@ -22,6 +22,8 @@
 #
 # You should have received a copy of the GNU LGPL-3.0 license
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import pytest
+import os.path as osp
 
 try:
     # make sure we import QtWebEngineWidgets at the start
@@ -40,3 +42,8 @@ def pytest_configure(config):
     if config.getoption('ref'):
         import unittest
         unittest.TestLoader.testMethodPrefix = 'ref'
+
+
+@pytest.fixture
+def regular_test_file():
+    return osp.join(osp.dirname(__file__), "test-t2m-u-v.nc")

tests/test_plotters_vectorplotter.py

@@ -175,5 +175,20 @@ class VectorPlotterTest2D(bt.TestBase2D, VectorPlotterTest):
     var = ['u_2d', 'v_2d']
 
 
+def test_density_with_lonlatbox(regular_test_file):
+    """Test that the lonlatbox still works with density.
+
+    see https://github.com/psyplot/psy-maps/issues/43
+    """
+    sp = psy.plot.mapvector(
+        regular_test_file, name=[["u", "v"]], density=0.5, lonlatbox="Europe"
+    )
+    ax = sp.plotters[0].ax
+    xmin, xmax, ymin, ymax = ax.get_extent()
+    assert xmax - xmin < 180
+    assert ymax - ymin < 90
+
+
+
 if __name__ == '__main__':
     unittest.main()