Made it possible to use projection other than GOOGLE_MERCATOR in bokeh

geoviews/plotting/bokeh/__init__.py

@@ -3,6 +3,7 @@
 import param
 import numpy as np
 import shapely.geometry
+from cartopy.crs import GOOGLE_MERCATOR
 from bokeh.models import WMTSTileSource, BBoxTileSource, QUADKEYTileSource
 
 from holoviews import Store, Overlay, NdOverlay
@@ -24,7 +25,7 @@
                           project_path, project_graph, project_quadmesh)
 from ...tile_sources import _ATTRIBUTIONS
 from ...util import geom_to_array
-from .plot import GeoPlot, OverlayPlot, DEFAULT_PROJ
+from .plot import GeoPlot, OverlayPlot
 from . import callbacks # noqa
 
 line_types = (shapely.geometry.MultiLineString, shapely.geometry.LineString)
@@ -37,7 +38,8 @@ class TilePlot(GeoPlot):
     def get_extents(self, element, ranges):
         extents = super(TilePlot, self).get_extents(element, ranges)
         if not self.overlaid and all(e is None or not np.isfinite(e) for e in extents):
-            global_extent = (-20026376.39, -20048966.10, 20026376.39, 20048966.10)
+            (x0, x1), (y0, y1) = GOOGLE_MERCATOR.x_limits, GOOGLE_MERCATOR.y_limits
+            global_extent = (x0, y0, x1, y1)
             return global_extent
         return extents
 
@@ -150,8 +152,8 @@ def get_data(self, element, ranges, style):
         if self.static_source:
             data = {}
         else:
-            if self.geographic and element.crs != DEFAULT_PROJ:
-                element = project_shape(element)
+            if self.geographic and element.crs != self.projection:
+                element = project_shape(element, projection=self.projection)
             xs, ys = geom_to_array(element.geom()).T
             if self.invert_axes: xs, ys = ys, xs
             data = dict(xs=[xs], ys=[ys])
@@ -213,7 +215,7 @@ def get_data(self, element, ranges, style):
             self._plot_methods = dict(single='multi_line')
         else:
             self._plot_methods = dict(single='patches', batched='patches')
-        geoms = [DEFAULT_PROJ.project_geometry(geom, element.crs)
+        geoms = [self.projection.project_geometry(geom, element.crs)
                  for geom in geoms]
         xs, ys = zip(*(geom_to_array(geom).T for geom in geoms))
         data = dict(xs=list(xs), ys=list(ys))
@@ -227,8 +229,8 @@ def get_data(self, element, ranges, style):
         if not self.geographic:
             return super(GeoTextPlot, self).get_data(element, ranges, style)
         if element.crs:
-            x, y = DEFAULT_PROJ.transform_point(element.x, element.y,
-                                                element.crs)
+            x, y = self.projection.transform_point(element.x, element.y,
+                                                   element.crs)
         return (dict(x=[x], y=[y], text=[element.text]), mapping, style)
 
     def get_extents(self, element, ranges=None):

geoviews/plotting/bokeh/callbacks.py

@@ -11,7 +11,7 @@
                                MouseLeave, Bounds, BoundsXY)
 
 from ...util import project_extents
-from .plot import DEFAULT_PROJ, OverlayPlot
+from .plot import OverlayPlot
 
 
 def get_cb_plot(cb, plot=None):
@@ -50,7 +50,7 @@ def project_ranges(cb, msg, attributes):
     x0, x1 = msg.get('x_range', (0, 1000))
     y0, y1 = msg.get('y_range', (0, 1000))
     extents = x0, y0, x1, y1
-    x0, y0, x1, y1 = project_extents(extents, DEFAULT_PROJ,
+    x0, y0, x1, y1 = project_extents(extents, plot.projection,
                                      plot.current_frame.crs)
     coords = {'x_range': (x0, x1), 'y_range': (y0, y1)}
     return {k: v for k, v in coords.items() if k in attributes}
@@ -64,7 +64,7 @@ def project_point(cb, msg, attributes=('x', 'y')):
     plot = get_cb_plot(cb)
     x, y = msg.get('x', 0), msg.get('y', 0)
     crs = plot.current_frame.crs
-    coordinates = crs.transform_points(DEFAULT_PROJ, np.array([x]), np.array([y]))
+    coordinates = crs.transform_points(plot.projection, np.array([x]), np.array([y]))
     msg['x'], msg['y'] = coordinates[0, :2]
     return {k: v for k, v in msg.items() if k in attributes}
 
@@ -95,7 +95,7 @@ def _process_msg(self, msg):
         msg = super(GeoBoundsXYCallback, self)._process_msg(msg)
         if skip(self, msg, ('bounds',)): return msg
         plot = get_cb_plot(self)
-        msg['bounds'] = project_extents(msg['bounds'], DEFAULT_PROJ,
+        msg['bounds'] = project_extents(msg['bounds'], plot.projection,
                                         plot.current_frame.crs)
         return msg
 
@@ -107,7 +107,7 @@ def _process_msg(self, msg):
         if skip(self, msg, ('boundsx',)): return msg
         x0, x1 = msg['boundsx']
         plot = get_cb_plot(self)
-        x0, _, x1, _ = project_extents((x0, 0, x1, 0), DEFAULT_PROJ,
+        x0, _, x1, _ = project_extents((x0, 0, x1, 0), plot.projection,
                                         plot.current_frame.crs)
         return {'boundsx': (x0, x1)}
 
@@ -119,7 +119,7 @@ def _process_msg(self, msg):
         if skip(self, msg, ('boundsy',)): return msg
         y0, y1 = msg['boundsy']
         plot = get_cb_plot(self)
-        _, y0, _, y1 = project_extents((0, y0, 0, y1), DEFAULT_PROJ,
+        _, y0, _, y1 = project_extents((0, y0, 0, y1), plot.projection,
                                         plot.current_frame.crs)
         return {'boundsy': (y0, y1)}
 

geoviews/plotting/bokeh/plot.py

@@ -15,7 +15,6 @@
 from ...element import is_geographic, _Element
 from ...util import project_extents
 
-DEFAULT_PROJ = GOOGLE_MERCATOR
 
 class GeoPlot(ElementPlot):
     """
@@ -34,6 +33,10 @@ class GeoPlot(ElementPlot):
     show_grid = param.Boolean(default=False, doc="""
         Whether to show gridlines on the plot.""")
 
+    projection = param.Parameter(default=GOOGLE_MERCATOR, doc="""
+        Allows supplying a custom projection to transform the axis
+        coordinates during display. Defaults to GOOGLE_MERCATOR.""")
+
     # Project operation to apply to the element
     _project_operation = None
 
@@ -54,7 +57,8 @@ def _axis_properties(self, axis, key, plot, dimension=None,
                          ax_mapping={'x': 0, 'y': 1}):
         axis_props = super(GeoPlot, self)._axis_properties(axis, key, plot,
                                                            dimension, ax_mapping)
-        if self.geographic:
+        proj = self.projection
+        if self.geographic and proj is GOOGLE_MERCATOR:
             dimension = 'lon' if axis == 'x' else 'lat'
             axis_props['ticker'] = MercatorTicker(dimension=dimension)
             axis_props['formatter'] = MercatorTickFormatter(dimension=dimension)
@@ -99,24 +103,28 @@ def get_extents(self, element, ranges):
         set_extent method to project the extents to the
         Elements coordinate reference system.
         """
+
+        proj = self.projection
         if self.is_global:
-            return (-20026376.39, -20048966.10, 20026376.39, 20048966.10)
+            (x0, x1), (y0, y1) = proj.x_limits, proj.y_limits
+            return (x0, y0, x1, y1)
         extents = super(GeoPlot, self).get_extents(element, ranges)
         if not getattr(element, 'crs', None) or not self.geographic:
             return extents
         elif any(e is None or not np.isfinite(e) for e in extents):
             extents = None
         else:
             try:
-                extents = project_extents(extents, element.crs, DEFAULT_PROJ)
+                extents = project_extents(extents, element.crs, proj)
             except:
                 extents = None
         return (np.NaN,)*4 if not extents else extents
 
 
     def get_data(self, element, ranges, style):
-        if self._project_operation and self.geographic and element.crs != DEFAULT_PROJ:
-            element = self._project_operation(element)
+        proj = self.projection
+        if self._project_operation and self.geographic and element.crs != proj:
+            element = self._project_operation(element, projection=proj)
         return super(GeoPlot, self).get_data(element, ranges, style)