Added fixes for longitude wrapping when projecting Image

geoviews/element/geo.py

@@ -136,6 +136,9 @@ def __init__(self, data, kdims=None, vdims=None, **params):
                             % type(data).__name__)
         super(Feature, self).__init__(data, kdims=kdims, vdims=vdims, **params)
 
+    def __call__(self, *args, **kwargs):
+        return self.opts(*args, **kwargs)
+
     def range(self, dim, data_range=True, dimension_range=True):
         didx = self.get_dimension_index(dim)
         if didx in [0, 1] and data_range:

geoviews/operation/projection.py

@@ -228,7 +228,7 @@ def _process_element(self, element):
             if np.all(X[0, 1:] < X[0, :-1]):
                 X = X[:, ::-1]
             Y = element.interface.coords(element, 1, True, True, False)
-            if np.all(Y[1:, 0] > X[:-1, 0]):
+            if np.all(Y[1:, 0] < Y[:-1, 0]):
                 Y = Y[::-1, :]
 
         if X.shape != zs.shape:
@@ -302,8 +302,6 @@ def _process(self, img, key=None):
         if self.p.fast:
             return self._fast_process(img, key)
         proj = self.p.projection
-        if proj == img.crs:
-            return img
         x0, x1 = img.range(0)
         y0, y1 = img.range(1)
         xn, yn = img.interface.shape(img, gridded=True)[:2]
@@ -319,10 +317,11 @@ def _process(self, img, key=None):
             else:
                 projected, extents = arr, trgt_ext
             arrays.append(projected)
-        projected = np.dstack(arrays) if len(arrays) > 1 else arrays[0]
-        data = np.flipud(projected)
-        bounds = (extents[0], extents[2], extents[1], extents[3])
-        return img.clone(data, bounds=bounds, kdims=img.kdims,
+        xunit = ((extents[1]-extents[0])/float(xn))/2.
+        yunit = ((extents[3]-extents[2])/float(yn))/2.
+        xs = np.linspace(extents[0]+xunit, extents[1]-xunit, xn)
+        ys = np.linspace(extents[2]+yunit, extents[3]-yunit, yn)
+        return img.clone((xs, ys, *arrays), bounds=None, kdims=img.kdims,
                          vdims=img.vdims, crs=proj, xdensity=None,
                          ydensity=None)
 

geoviews/tests/testprojection.py

@@ -0,0 +1,37 @@
+import numpy as np
+import cartopy.crs as ccrs
+
+from geoviews.element import Image
+from geoviews.element.comparison import ComparisonTestCase
+from geoviews.operation import project
+
+
+class TestProjection(ComparisonTestCase):
+
+    def test_image_latlon360_wrapping(self):
+        xs = np.linspace(0, 360, 5)
+        ys = np.linspace(-90, 90, 3)
+        img = Image((xs, ys, xs[np.newaxis, :]*ys[:, np.newaxis]))
+        proj = project(img, projection=ccrs.PlateCarree())
+        zs = proj.dimension_values('z', flat=False)
+        self.assertEqual(zs, np.array([
+            [-24300.,     -0.,  -8100.],
+            [     0.,      0.,      0.],
+            [     0.,      0.,      0.],
+            [     0.,      0.,      0.],
+            [ 24300.,      0.,   8100.]
+        ]))
+
+    def test_image_project_latlon_to_mercator(self):
+        xs = np.linspace(0, 360, 5)
+        ys = np.linspace(-90, 90, 3)
+        img = Image((xs, ys, xs[np.newaxis, :]*ys[:, np.newaxis]))
+        proj = project(img)
+        zs = proj.dimension_values('z', flat=False)
+        self.assertEqual(zs, np.array([
+            [-24300.,     -0.,  -8100.],
+            [-24300.,     -0.,  -8100.],
+            [     0.,      0.,      0.],
+            [ 24300.,      0.,   8100.],
+            [ 24300.,      0.,   8100.]
+        ]))

setup.py

@@ -128,8 +128,8 @@ def package_assets(example_path):
 
 _required = [
     'bokeh >=0.12.15',
-    'cartopy >=0.14.2',  # prevents pip alone (requires external package manager)
-    'holoviews >=1.11.0a9',
+    'cartopy >=0.16.0',  # prevents pip alone (requires external package manager)
+    'holoviews ==1.11.0a11',
     'numpy >=1.0',
     'param >=1.6.1'
 ]