general.py 文件源码

def findClosestVector(point, arr_shape=None, pixel_shape=None, xyorig=None):
    '''
    Finds the closest vector of array coordinates (x, y) from an input vector of pixel coordinates (x, y).

    Parameters:
        point : tuple
            Original point of interest in pixel units, order of (x,y)
        arr_shape : tuple
            Shape of data array in (x,y) order
        pixel_shape : tuple
            Shape of image in pixels in (x,y) order
        xyorig : str
            Indicates the origin point of coordinates.  Set to "relative" switches to an array coordinate
            system relative to galaxy center.  Default is absolute array coordinates (x=0, y=0) = upper left corner

    Returns:
        minind : tuple
            A tuple of array coordinates in x, y order
    '''

    # set as numpy arrays
    arr_shape = np.array(arr_shape, dtype=int)
    pixel_shape = np.array(pixel_shape, dtype=int)

    # compute midpoints
    xmid, ymid = arr_shape/2
    xpixmid, ypixmid = pixel_shape/2

    # default absolute array coordinates
    xcoords = np.array([0, arr_shape[0]], dtype=int)
    ycoords = np.array([0, arr_shape[1]], dtype=int)

    # split x,y coords and pixel coords
    x1, x2 = xcoords
    y1, y2 = ycoords
    xpix, ypix = pixel_shape

    # build interpolates between array coordinates and pixel coordinates
    points = [[x1, y1], [x1, y2], [xmid, ymid], [x2, y1], [x2, y2]]
    values = [[0, ypix], [0, 0], [xpixmid, ypixmid], [xpix, ypix], [xpix, 0]]  # full image
    # values = [[xpixmid-xmid, ypixmid+ymid], [xpixmid-xmid, ypixmid-ymid], [xpixmid, ypixmid], [xpixmid+xmid, ypixmid+ymid], [xpixmid+xmid, ypixmid-ymid]]  # pixels based on arr_shape
    #values = [[xpixmid-x2, ypixmid+y2], [xpixmid-x2, ypixmid-y2], [xpixmid, ypixmid], [xpixmid+x2, ypixmid+y2], [xpixmid+x2, ypixmid-y2]]  # pixels based on arr_shape

    # make 2d array of array indices in absolute or (our) relative coordindates
    arrinds = np.mgrid[x1:x2, y1:y2].swapaxes(0, 2).swapaxes(0, 1)
    # interpolate a new 2d pixel coordinate array
    final = griddata(points, values, arrinds)

    # find minimum array vector closest to input coordinate point
    diff = np.abs(point - final)
    prod = diff[:, :, 0]*diff[:, :, 1]
    minind = np.unravel_index(prod.argmin(), arr_shape)

    # toggle relative array coordinates
    if xyorig in ['relative', 'center']:
        minind = np.array(minind, dtype=int)
        xmin = minind[0] - xmid
        ymin = ymid - minind[1]
        minind = (xmin, ymin)

    return minind