Add support for ImageStack

geoviews/__init__.py

@@ -9,7 +9,7 @@
 from .annotators import annotate # noqa (API import)
 from .element import ( # noqa (API import)
     _Element, Feature, Tiles, WMTS, LineContours, FilledContours,
-    Text, Image, Points, Path, Polygons, Shape, Dataset, RGB,
+    Text, Image, ImageStack, Points, Path, Polygons, Shape, Dataset, RGB,
     Contours, Graph, TriMesh, Nodes, EdgePaths, QuadMesh, VectorField,
     HexTiles, Labels, Rectangles, Segments, WindBarbs
 )

geoviews/element/__init__.py

@@ -4,7 +4,7 @@
 )
 
 from .geo import (_Element, Feature, Tiles, is_geographic,     # noqa (API import)
-                  WMTS, Points, Image, Text, LineContours, RGB,
+                  WMTS, Points, Image, ImageStack, Text, LineContours, RGB,
                   FilledContours, Path, Polygons, Shape, Dataset,
                   Contours, TriMesh, Graph, Nodes, EdgePaths, QuadMesh,
                   VectorField, Labels, HexTiles, Rectangles, Segments, WindBarbs)
@@ -51,6 +51,9 @@ def filledcontours(self, kdims=None, vdims=None, mdims=None, **kwargs):
     def image(self, kdims=None, vdims=None, mdims=None, **kwargs):
         return self(Image, kdims, vdims, mdims, **kwargs)
 
+    def image_stack(self, kdims=None, vdims=None, mdims=None, **kwargs):
+        return self(ImageStack, kdims, vdims, mdims, **kwargs)
+
     def points(self, kdims=None, vdims=None, mdims=None, **kwargs):
         if kdims is None: kdims = self._element.kdims
         el_type = Points if is_geographic(self._element, kdims) else HvPoints

geoviews/element/comparison.py

@@ -2,14 +2,15 @@
 
 from holoviews.element.comparison import Comparison as HvComparison
 
-from .geo import Image, Points, LineContours, FilledContours, WindBarbs
+from .geo import Image, ImageStack, Points, LineContours, FilledContours, WindBarbs
 
 class Comparison(HvComparison):
 
     @classmethod
     def register(cls):
         super().register()
         cls.equality_type_funcs[Image] = cls.compare_dataset
+        cls.equality_type_funcs[ImageStack] = cls.compare_dataset
         cls.equality_type_funcs[Points] = cls.compare_dataset
         cls.equality_type_funcs[LineContours] = cls.compare_dataset
         cls.equality_type_funcs[FilledContours] = cls.compare_dataset

geoviews/element/geo.py

@@ -10,9 +10,9 @@
 from holoviews.core import util
 from holoviews.element import (
     Contours as HvContours, Graph as HvGraph, Image as HvImage,
-    Nodes as HvNodes, Path as HvPath, Polygons as HvPolygons,
-    RGB as HvRGB, Text as HvText, TriMesh as HvTriMesh,
-    QuadMesh as HvQuadMesh, Points as HvPoints,
+    ImageStack as HvImageStack, Nodes as HvNodes, Path as HvPath,
+    Polygons as HvPolygons, RGB as HvRGB, Text as HvText,
+    TriMesh as HvTriMesh, QuadMesh as HvQuadMesh, Points as HvPoints,
     VectorField as HvVectorField, HexTiles as HvHexTiles,
     Labels as HvLabels, Rectangles as HvRectangles,
     Segments as HvSegments, Geometry as HvGeometry,
@@ -401,6 +401,39 @@ def from_xarray(cls, da, crs=None, apply_transform=False,
         return from_xarray(da, crs, apply_transform, **kwargs)
 
 
+class ImageStack(_Element, HvImageStack):
+    """
+    ImageStack expands the capabilities of Image to by supporting
+    multiple layers of images.
+
+    As there is many ways to represent multiple layers of images,
+    the following options are supported:
+
+        1) A 3D Numpy array with the shape (y, x, level)
+        2) A list of 2D Numpy arrays with identical shape (y, x)
+        3) A dictionary where the keys will be set as the vdims and the
+            values are 2D Numpy arrays with identical shapes (y, x).
+            If the dictionary's keys matches the kdims of the element,
+            they need to be 1D arrays.
+        4) A tuple containing (x, y, level_0, level_1, ...),
+            where the level is a 2D Numpy array in the shape of (y, x).
+        5) An xarray DataArray or Dataset where its `coords` contain the kdims.
+
+    If no kdims are supplied, x and y are used.
+
+    If no vdims are supplied, and the naming can be inferred like with a dictionary
+    the levels will be named level_0, level_1, etc.
+    """
+
+    vdims = param.List(doc="""
+        The dimension description of the data held in the matrix.""")
+
+    group = param.String(default='ImageStack', constant=True)
+
+    _ndim = 3
+
+    _vdim_reductions = {1: Image}
+
 
 class QuadMesh(_Element, HvQuadMesh):
     """

geoviews/plotting/bokeh/__init__.py

@@ -14,10 +14,10 @@
 from holoviews.plotting.bokeh.graphs import TriMeshPlot, GraphPlot
 from holoviews.plotting.bokeh.hex_tiles import hex_binning, HexTilesPlot
 from holoviews.plotting.bokeh.path import PolygonPlot, PathPlot, ContourPlot
-from holoviews.plotting.bokeh.raster import RasterPlot, RGBPlot, QuadMeshPlot
+from holoviews.plotting.bokeh.raster import RasterPlot, RGBPlot, QuadMeshPlot, ImageStackPlot
 
 from ...element import (
-    WMTS, Points, Polygons, Path, Contours, Shape, Image, Feature,
+    WMTS, Points, Polygons, Path, Contours, Shape, Image, ImageStack, Feature,
     Text, RGB, Nodes, EdgePaths, Graph, TriMesh, QuadMesh, VectorField,
     Labels, HexTiles, LineContours, FilledContours, Rectangles, Segments
 )
@@ -140,6 +140,11 @@ class GeoRGBPlot(GeoPlot, RGBPlot):
     _project_operation = project_image.instance(fast=False)
 
 
+class GeoImageStackPlot(GeoPlot, ImageStackPlot):
+
+    _project_operation = project_image.instance(fast=False)
+
+
 class GeoPolygonPlot(GeoPlot, PolygonPlot):
 
     _project_operation = project_path
@@ -293,6 +298,7 @@ def _process(self, element, key=None):
                 Path: GeoPathPlot,
                 Shape: GeoShapePlot,
                 Image: GeoRasterPlot,
+                ImageStack: GeoImageStackPlot,
                 RGB: GeoRGBPlot,
                 LineContours: LineContourPlot,
                 FilledContours: FilledContourPlot,

geoviews/plotting/mpl/__init__.py

@@ -27,7 +27,7 @@
 
 
 from ...element import (
-    Image, Points, Feature, WMTS, Tiles, Text, LineContours,
+    Image, ImageStack, Points, Feature, WMTS, Tiles, Text, LineContours,
     FilledContours, is_geographic, Path, Polygons, Shape, RGB,
     Contours, Nodes, EdgePaths, Graph, TriMesh, QuadMesh, VectorField,
     HexTiles, Labels, Rectangles, Segments, WindBarbs
@@ -246,7 +246,6 @@ def update_handles(self, *args):
         return GeoPlot.update_handles(self, *args)
 
 
-
 class GeoQuadMeshPlot(GeoPlot, QuadMeshPlot):
 
     _project_operation = project_quadmesh
@@ -288,6 +287,24 @@ def update_handles(self, *args):
         return GeoPlot.update_handles(self, *args)
 
 
+class GeoImageStackPlot(GeoImagePlot):
+
+    style_opts = ['alpha', 'cmap', 'visible', 'filterrad', 'clims', 'norm']
+
+    def __init__(self, element, **params):
+        super().__init__(element, **params)
+
+    def get_data(self, element, ranges, style):
+        self._norm_kwargs(element, ranges, style, element.vdims[0])
+        style.pop('interpolation', None)
+        xs, ys, zs = geo_mesh(element)
+        xs = GridInterface._infer_interval_breaks(xs)
+        ys = GridInterface._infer_interval_breaks(ys)
+        if self.geographic:
+            style['transform'] = element.crs
+        return (xs, ys, zs), style, {}
+
+
 class GeoPointPlot(GeoPlot, PointPlot):
     """
     Draws a scatter plot from the data in a Points Element.
@@ -587,6 +604,7 @@ def draw_annotation(self, axis, data, crs, opts):
                 Path: GeoPathPlot,
                 Contours: GeoContourPlot,
                 RGB: GeoRGBPlot,
+                ImageStack: GeoImageStackPlot,
                 Shape: GeoShapePlot,
                 Graph: GeoGraphPlot,
                 TriMesh: GeoTriMeshPlot,

geoviews/util.py

@@ -747,6 +747,8 @@ def from_xarray(da, crs=None, apply_transform=False, nan_nodata=False, **kwargs)
         from .element.geo import RGB, HvRGB
         el = RGB if 'crs' in kwargs else HvRGB
         vdims = el.vdims[:bands]
+        if bands == 4:
+            vdims.append("A")
         el = el(data, [x, y], vdims, **kwargs)
     if hasattr(el.data, 'attrs'):
         el.data.attrs = da.attrs