set clon and clat to 0 only for global files

CHANGELOG.rst

@@ -16,6 +16,11 @@ Changed
   see `#4 <https://github.com/psyplot/psy-maps/pull/4>`__
 * the default values for the `transform` and `projection` formatoptions are now
   ``'cf'`` (see `#5 <https://github.com/psyplot/psy-maps/pull/5>`__)
+* ``clat`` now always takes the mean latitude of the data if the formatoption
+  value is None and the data does not span the entire latitudinal range. At the
+  same time, ``clon`` now takes the mean longitude of the data if the
+  formatoption value is None and the data does not span the entire longitudinal
+  range (see `#8 <https://github.com/psyplot/psy-maps/pull/8>`__)
 
 v1.2.0
 ======

psy_maps/plotters.py

@@ -593,10 +593,12 @@ def update(self, value):
                     value = None
             else:
                 self.clon = value
-        if value is None and self.lonlatbox.value is not None:
-            self.clon = self.lon_mean
-        elif value is None:
-            self.clon = 0.0
+        if value is None:
+            lonmin, lonmax = self.lonlatbox.lonlatbox[:2]
+            if lonmax - lonmin > 350:
+                self.clon = 0.0
+            else:
+                self.clon = self.lon_mean
 
 
 class CenterLat(BoxBase):
@@ -631,10 +633,12 @@ def update(self, value):
                     value = None
             else:
                 self.clat = value
-        if value is None and self.lonlatbox.value is not None:
-            self.clat = self.lat_mean
-        elif value is None:
-            self.clat = 0.0
+        if value is None:
+            latmin, latmax = self.lonlatbox.lonlatbox[2:]
+            if latmax - latmin > 170:
+                self.clat = 0
+            else:
+                self.clat = self.lat_mean
 
 
 @docstrings.get_sectionsf('LonLatBox')

tests/test_plotters.py

@@ -437,8 +437,9 @@ def test_lonlatbox(self):
         sp = psy.plot.mapplot(os.path.join(bt.test_dir, 'Stockholm.nc'),
                               name='Population', transform='moll')
         ax = sp.plotters[0].ax
-        self.assertEqual(np.round(ax.get_extent(), 2).tolist(),
-                         [17.66, 18.39, 59.1, 59.59])
+        self.assertEqual(
+            np.round(ax.get_extent(ccrs.PlateCarree()), 2).tolist(),
+            [17.66, 18.39, 59.1, 59.59])
         sp.update(lonlatbox=[17.8, 18.2, 59.2, 59.4])
         self.assertEqual(
             np.round(ax.get_extent(ccrs.PlateCarree()), 2).tolist(),

tests/test_projections.py

@@ -33,20 +33,47 @@ def grid(request):
 
 
 @pytest.fixture
-def grid_ds(grid):
-    return psyd.open_dataset(osp.join(bt.test_dir, 'grids', grid + '.nc'))
+def open_grid_ds():
+    open_datasets = []
+    def _grid_ds(grid):
+        ds = psyd.open_dataset(osp.join(bt.test_dir, 'grids', grid + '.nc'))
+        open_datasets.append(ds)
+        return ds
+    yield _grid_ds
+    for ds in open_datasets:
+        ds.close()
 
 
 @pytest.fixture
 def grid_projection(grid):
     return projection_mapping[grid]
 
 
-def test_grid_plotting(grid_ds, grid, grid_projection):
+def test_grid_plotting(open_grid_ds, grid, grid_projection):
+    grid_ds = open_grid_ds(grid)
     with grid_ds.psy.plot.mapplot() as sp:
         assert len(sp) == 1
         plotter = sp.plotters[0]
         assert isinstance(plotter.transform.projection, grid_projection)
         assert plotter.plot._kwargs.get('transform') is \
             plotter.transform.projection
-        assert isinstance(plotter.projection.projection, grid_projection)
+        assert isinstance(plotter.projection.projection, grid_projection)
+
+
+@pytest.mark.parametrize(
+    "grid,clon", [("rotated_latitude_longitude", 11),
+                  (osp.join("..", "test-t2m-u-v"), 0)])
+def test_clon_centering(open_grid_ds, grid, clon):
+    grid_ds = open_grid_ds(grid)
+    with grid_ds.psy.plot.mapplot(projection='ortho') as sp:
+        plotter = sp.plotters[0]
+        assert plotter.clon.clon == pytest.approx(clon, abs=1)
+
+@pytest.mark.parametrize(
+    "grid,clat", [("rotated_latitude_longitude", 51),
+                  (osp.join("..", "test-t2m-u-v"), 0)])
+def test_clat_centering(open_grid_ds, grid, clat):
+    grid_ds = open_grid_ds(grid)
+    with grid_ds.psy.plot.mapplot(projection='ortho') as sp:
+        plotter = sp.plotters[0]
+        assert plotter.clat.clat == pytest.approx(clat, abs=1)