gridshow vs imshow, adds meshgrid and idx array methods

CMap2D.pyx

@@ -568,6 +568,55 @@ cdef class CMap2D:
         min_distances[self.occupancy() > self.thresh_free] *= -1.
         return min_distances
 
+    def as_idx_array(self, axis=None):
+        """ Returns an array of shape a containing indices for a
+
+        Parameters
+        ----------
+        a : array_like
+            Array to be reshaped.
+        axis : int, None, list of ints, or 'all'
+            Axis along which to return indices. If None, the flat index.
+
+        Returns
+        -------
+        result : ndarray
+            Array of shape (a.shape, len(axis))
+            if axis is None or a single int, (a.shape,)
+        """
+        a = self.occupancy()
+        if axis is None:
+            return np.arange(len(a.flatten())).reshape(a.shape)
+        idxs = np.array(np.where(np.ones(a.shape))).T.reshape(a.shape + (-1,))
+        if axis == "all":
+            return idxs
+        return idxs[..., axis]
+
+    def as_xy_array(self):
+        """ returns an array containing xy coordinates at every cell """
+        idxarray = self.as_idx_array(axis='all')
+        flatidxarray = idxarray.reshape((-1, 2))
+        flatxyarray = self.ij_to_xy(flatidxarray)
+        xyarray = flatxyarray.reshape(idxarray.shape)
+        return xyarray
+
+    def as_meshgrid_ij(self):
+        """ returns a tuple of 2 arrays with same dimension as map, containing respectively 
+        i and j indices of each cell
+        ii, jj = map2d.as_meshgrid_ij()
+        """
+        idxarray = self.as_idx_array(axis='all')
+        ii, jj = np.moveaxis(idxarray, -1, 0)
+        return (ii, jj)
+
+    def as_meshgrid_xy(self):
+        """ returns a tuple of 2 arrays with same dimension as map, containing respectively 
+        x and y indices of each cell
+        xx, yy = map2d.as_meshgrid_xy()
+        """
+        xx, yy = np.moveaxis(self.as_xy_array(), -1, 0)
+        return (xx, yy)
+
     cpdef as_coarse_map2d(self, n=1):
         # recursion to provide a convenient way to coarsen x times
         if n > 1:

setup.py

@@ -12,7 +12,7 @@
     long_description=long_description,
     long_description_content_type='text/markdown',
     url="https://github.com/danieldugas/pymap2d",
-    version='0.1.7',
+    version='0.1.8',
     py_modules=['map2d', 'pose2d', 'circular_index', 'map2d_ros_tools'],
     ext_modules=cythonize("CMap2D.pyx", annotate=True),
     include_dirs=[numpy.get_include()],

test/example_gridshow.py

@@ -0,0 +1,37 @@
+import numpy as np
+import matplotlib.pyplot as plt
+from CMap2D import gridshow, CMap2D
+
+cmap2d = CMap2D().as_coarse_map2d(3)
+cmap2d.set_resolution(1.)
+cmap2d.origin[0] = -5
+cmap2d.origin[1] = -5
+cmap2d._occupancy[2:4, 8:10] = 1.
+cmap2d._occupancy[8:10, 8:9] = 1.
+ii, jj = cmap2d.as_meshgrid_ij()
+xx, yy = cmap2d.as_meshgrid_xy()
+rr = np.sqrt((xx-1) * (xx-1) + yy * yy)
+smile = np.logical_and.reduce((
+    rr > 3,
+    rr < 5,
+    yy < 0,
+))
+for i, j in np.array(np.where(smile)).T:
+    cmap2d._occupancy[i, j] = 1.
+
+
+fig, (ax1, ax2) = plt.subplots(1, 2)
+plt.sca(ax1)
+gridshow(cmap2d.occupancy(), extent=cmap2d.get_extent_xy())
+plt.title("gridshow")
+plt.xlabel("x")
+plt.ylabel("y")
+plt.sca(ax2)
+plt.title("plt.imshow")
+e = cmap2d.get_extent_xy()
+imshow_extent = [e[2], e[3], e[1], e[0]]
+plt.imshow(cmap2d.occupancy(), extent=imshow_extent)
+plt.xlabel("y")
+plt.ylabel("x (descending)")
+
+plt.show()