wradlib.georef.polar.centroid_to_polyvert#
- wradlib.georef.polar.centroid_to_polyvert(centroid, delta, /)[source]#
Calculates the 2-D Polygon vertices necessary to form a rectangular polygon around the centroid’s coordinates.
The vertices order will be clockwise, as this is the convention used by ESRI’s shapefile format for a polygon.
- Parameters:
centroid (array-like) – List of 2-D coordinates of the center point of the rectangle.
delta (scalar or
numpy.ndarray
) – Symmetric distances of the vertices from the centroid in each direction. Ifdelta
is scalar, it is assumed to apply to both dimensions.
- Returns:
vertices (
numpy.ndarray
) – An array with 5 vertices per centroid.
Note
The function can currently only deal with 2-D data (If you come up with a higher dimensional version of ‘clockwise’ you’re welcome to add it). The data is then assumed to be organized within the
centroid
array with the last dimension being the 2-D coordinates of each point.Examples
>>> centroid_to_polyvert([0., 1.], [0.5, 1.5]) array([[-0.5, -0.5], [-0.5, 2.5], [ 0.5, 2.5], [ 0.5, -0.5], [-0.5, -0.5]]) >>> centroid_to_polyvert(np.arange(4).reshape((2,2)), 0.5) array([[[-0.5, 0.5], [-0.5, 1.5], [ 0.5, 1.5], [ 0.5, 0.5], [-0.5, 0.5]], [[ 1.5, 2.5], [ 1.5, 3.5], [ 2.5, 3.5], [ 2.5, 2.5], [ 1.5, 2.5]]])