mpl.colors.LightSource.shade_rgb

LightSource.shade_rgb(rgb, elevation, fraction=1.0, blend_mode=u'hsv', vert_exag=1, dx=1, dy=1, **kwargs)

Take the input RGB array (ny*nx*3) adjust their color values to given the impression of a shaded relief map with a specified light source using the elevation (ny*nx). A new RGB array ((ny*nx*3)) is returned.

Parameters:

rgb : array-like

An MxNx3 RGB array, assumed to be in the range of 0 to 1.

elevation : array-like

A 2d array (or equivalent) of the height values used to generate a shaded map.

fraction : number

Increases or decreases the contrast of the hillshade. Values greater than one will cause intermediate values to move closer to full illumination or shadow (and clipping any values that move beyond 0 or 1). Note that this is not visually or mathematically the same as vertical exaggeration.

blend_mode : {‘hsv’, ‘overlay’, ‘soft’} or callable, optional

The type of blending used to combine the colormapped data values with the illumination intensity. For backwards compatibility, this defaults to “hsv”. Note that for most topographic surfaces, “overlay” or “soft” appear more visually realistic. If a user-defined function is supplied, it is expected to combine an MxNx3 RGB array of floats (ranging 0 to 1) with an MxNx1 hillshade array (also 0 to 1). (Call signature func(rgb, illum, **kwargs)) Additional kwargs supplied to this function will be passed on to the blend_mode function.

vert_exag : number, optional

The amount to exaggerate the elevation values by when calculating illumination. This can be used either to correct for differences in units between the x-y coordinate system and the elevation coordinate system (e.g. decimal degrees vs meters) or to exaggerate or de-emphasize topography.

dx : number, optional

The x-spacing (columns) of the input elevation grid.

dy : number, optional

The y-spacing (rows) of the input elevation grid.

Additional kwargs are passed on to the *blend_mode* function.

Returns:

shaded_rgb : ndarray

An MxNx3 array of floats ranging between 0-1.