slippy.surface.PyramidSurface

class slippy.surface.PyramidSurface(lengths: Sequence, rotation: Optional[float] = None, shift: Optional[tuple] = None, generate: bool = False, grid_spacing: Optional[float] = None, extent: Optional[tuple] = None, shape: Optional[tuple] = None)

Pyramid surface with any slopes

Parameters

• lengths ({Sequence, float}) – The characteristic lengths of the pyramid in each direction, if a scalar is given the results is a square based pyramid with 45 degree sides

• rotation (float, optional (None)) – If set the surface will be rotated by this number of radians

• shift (tuple, optional (None)) – If set the surface will be shifted by this distance in the and y directions, tuple should be length 2, if not set the default is to shift by half the extent, meaning that the origin becomes the centre.

• generate (bool, optional (False)) – If True the surface profile is discretised on instantiation.

• grid_spacing (float, optional (None)) – The distance between grid points on the surface profile

• extent (tuple, optional (None)) – The overall size of the surface

• shape (tuple, optional (None)) – The number of grid points in each direction on the surface

See also

Surface

Notes

This is a subclass of Surface all functionality and attributes are available within this class.

All keyword arguments allowed for Surface are also allowed on instantiation of this class apart from the profile key word.

If the extent is findable on instantiation the surface will be shifted so the natural origin is in the centre of the extent. If the extent is not findable the natural origin will be at (0,0). For a round surface the natural origin is the centre of the ball.

Examples

Making an analytically defined square based pyramid:

>>> import slippy.surface as s
>>> my_surface = s.PyramidSurface((1,1,1), extent=(0.5,0.5))

Making a discretely defined square based pyramid:

>>> my_surface = s.PyramidSurface((1, 1, 3), extent=(0.5,0.5), grid_spacing=0.001, generate = True)

__init__(lengths: Sequence, rotation: Optional[float] = None, shift: Optional[tuple] = None, generate: bool = False, grid_spacing: Optional[float] = None, extent: Optional[tuple] = None, shape: Optional[tuple] = None)

Methods

__init__(lengths[, rotation, shift, ...])
convert_coordinates(y_coord, x_coord)
discretise()
find_summits([mask, four_nearest, ...])	Find summits after low pass filtering
get_acf([profile_in])	Find the auto correlation function of the surface
get_fft([profile_in])	Find the fourier transform of the surface
get_height_of_mat_vr(ratio[, void, mask, ...])	Find the height of a given material or void volume ratio
get_mat_vr(height[, void, mask, ratio])	Find the material or void volume ratio for a given height
get_points_from_extent([extent, ...])	Gets the grid points from the extent and the grid spacing
get_psd()	Find the power spectral density of the surface
get_summit_curvature([summits, mask, ...])	Get summit curvatures
height(x_mesh, y_mesh)	Find the height of the surface at specified points
interpolate(y_points, x_points[, mode, ...])	Easy memoized interpolation on surface objects
low_pass_filter(cut_off_freq[, return_copy])	Low pass FIR filter the surface profile
max_shape()
mesh(depth[, method, parameters])	Returns a Mesh object for the surface
resample([new_grid_spacing, return_profile, ...])	Resample or crop the profile by interpolation
rotate(radians)
roughness(parameter_name[, mask, ...])	Find areal roughness parameters
shift([shift])	Translate the profile of the surface
show([property_to_plot, plot_type, ax, ...])	Plot surface properties
subtract_polynomial(order[, mask])	Flatten the surface by subtracting a polynomial
wear(name, x_pts, y_pts, depth)	Add wear / geometry changes to the surface profile

Attributes

acf	The auto correlation function of the surface profile
dimensions	The number of spatial dimensions that
extent	The overall dimensions of the surface in the same units as grid spacing
fft	The fast fourier transform of the surface
grid_spacing	The distance between grid points in the x and y directions
is_analytic
is_discrete	A bool flag, True if there is a profile present
mask	A mask used to exclude some values from analysis, a single float or an array of bool the same size as profile Either a boolean array of size self.size or a float of the value to be excluded
material	A material object describing the properties of the surface
moving_surface
profile	The height data for the surface profile
psd	The power spectral density of the surface
shape	The shape of the surface profile array, the number of points in each direction
size	The total number of points in the surface
surface_type	A description of the surface type
unworn_profile
wear_volumes