Fix x ranges upon projection

geoviews/plotting/bokeh/callbacks.py

@@ -64,6 +64,10 @@ def project_ranges(cb, msg, attributes):
     extents = x0, y0, x1, y1
     x0, y0, x1, y1 = project_extents(extents, plot.projection,
                                      plot.current_frame.crs)
+    if plot._unwrap_lons and -180 <= x0 < 0 or -180 <= x1 < 0:
+        x0, x1 = x0 + 360, x1 + 360
+        if x0 > x1:
+            x0, x1 = x1, x0
     coords = {'x_range': (x0, x1), 'y_range': (y0, y1)}
     return {k: v for k, v in coords.items() if k in attributes}
 
@@ -118,7 +122,8 @@ class GeoRangeXYCallback(RangeXYCallback):
 
     def _process_msg(self, msg):
         msg = super()._process_msg(msg)
-        return project_ranges(self, msg, ('x_range', 'y_range'))
+        ranges = project_ranges(self, msg, ('x_range', 'y_range'))
+        return ranges
 
 class GeoRangeXCallback(RangeXCallback):
 

geoviews/plotting/bokeh/plot.py

@@ -3,7 +3,7 @@
 """
 import param
 
-from cartopy.crs import GOOGLE_MERCATOR, PlateCarree, Mercator
+from cartopy.crs import GOOGLE_MERCATOR, PlateCarree, Mercator, _CylindricalProjection
 from bokeh.models.tools import BoxZoomTool, WheelZoomTool
 from bokeh.models import MercatorTickFormatter, MercatorTicker, CustomJSHover
 from holoviews.core.dimension import Dimension
@@ -70,6 +70,11 @@ def __init__(self, element, **params):
                     'and disable the show_grid option.'
                 )
 
+        self._unwrap_lons = False
+        if isinstance(self.geographic, _CylindricalProjection):
+            x1, x2 = element.range(0)
+            self._unwrap_lons = 0 <= x1 <= 360 and 0 <= x2 <= 360
+
     def _axis_properties(self, axis, key, plot, dimension=None,
                          ax_mapping=None):
         if ax_mapping is None:

geoviews/tests/test_operation.py

@@ -14,3 +14,40 @@ def test_quadmesh_contoures_filled():
     p1 = gv.QuadMesh(ds, kdims=["lon", "lat"])
     p2 = contours(p1, filled=True)
     gv.renderer("bokeh").get_plot(p2)
+
+
+def test_unwrap_lons():
+    pytest.importorskip("datashader")
+    # Regression test for: https://github.com/holoviz/geoviews/pull/722
+    from holoviews.operation.datashader import rasterize
+    ds = xr.tutorial.open_dataset("air_temperature").isel(time=0)
+    p1 = gv.Image(ds)
+    p2 = rasterize(p1, filled=True)
+    gv.renderer("bokeh").get_plot(p2)
+    for x in p2.range(0):
+        assert x >= 0
+        assert x <= 360
+    p2.callback()
+    for x in p2.range(0):
+        assert x >= 0
+        assert x <= 360
+
+
+def test_no_unwrap_lons():
+    pytest.importorskip("datashader")
+    # Regression test for: https://github.com/holoviz/geoviews/pull/722
+    from holoviews.operation.datashader import rasterize
+    ds = xr.tutorial.open_dataset("air_temperature").isel(time=0)
+    # to -180, 180
+    ds["lon"] = (ds["lon"] + 180) % 360 - 180
+
+    p1 = gv.Image(ds)
+    p2 = rasterize(p1, filled=True)
+    gv.renderer("bokeh").get_plot(p2)
+    for x in p2.range(0):
+        assert x >= -180
+        assert x <= 180
+    p2.callback()
+    for x in p2.range(0):
+        assert x >= -180
+        assert x <= 180