Note

This section is only a reference describing the function, please see the chapter on mlab: Python scripting for 3D plotting for an introduction to mlab and how to interact with and assemble the functions of mlab.

Please see the section on Running mlab scripts for instructions on running the examples.

# Plotting functions¶

## barchart¶

mayavi.mlab.barchart(*args, **kwargs)

Plots vertical glyphs (like bars) scaled vertical, to do histogram-like plots.

This functions accepts a wide variety of inputs, with positions given in 2-D or in 3-D.

Function signatures:

```barchart(s, ...)
barchart(x, y, s, ...)
barchart(x, y, f, ...)
barchart(x, y, z, s, ...)
barchart(x, y, z, f, ...)
```

If only one positional argument is passed, it can be a 1-D, 2-D, or 3-D array giving the length of the vectors. The positions of the data points are deducted from the indices of array, and an uniformly-spaced data set is created.

If 3 positional arguments (x, y, s) are passed the last one must be an array s, or a callable, f, that returns an array. x and y give the 2D coordinates of positions corresponding to the s values.

If 4 positional arguments (x, y, z, s) are passed, the 3 first are arrays giving the 3D coordinates of the data points, and the last one is an array s, or a callable, f, that returns an array giving the data value.

Keyword arguments:

auto_scale:

whether to compute automatically the lateral scaling of the glyphs. This might be computationally expensive. Must be a boolean. Default: True

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

lateral_scale:

The lateral scale of the glyph, in units of the distance between nearest points Must be a float. Default: 0.9

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

If supplied, only one out of ‘mask_points’ data point is displayed. This option is useful to reduce the number of points displayed on large datasets Must be an integer or None.

mode:

The glyph used to represent the bars. Must be ‘2dcircle’ or ‘2dcross’ or ‘2ddiamond’ or ‘2dsquare’ or ‘2dthick_cross’ or ‘2dtriangle’ or ‘2dvertex’ or ‘cube’. Default: cube

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

resolution:

The resolution of the glyph created. For spheres, for instance, this is the number of divisions along theta and phi. Must be an integer. Default: 8

scale_factor:

the scaling applied to the glyphs. The size of the glyph is by default in drawing units. Must be a float. Default: 1.0

scale_mode:

the scaling mode for the glyphs (‘vector’, ‘scalar’, or ‘none’).

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_barchart():
""" Demo the bar chart plot with a 2D array.
"""
s = np.abs(np.random.random((3, 3)))
return barchart(s)
```

## contour3d¶

mayavi.mlab.contour3d(*args, **kwargs)

Plots iso-surfaces for a 3D volume of data supplied as arguments.

Function signatures:

```contour3d(scalars, ...)
contour3d(x, y, z, scalars, ...)
```

scalars is a 3D numpy arrays giving the data on a grid.

If 4 arrays, (x, y, z, scalars) are passed, the 3 first arrays give the position, and the last the scalar value. The x, y and z arrays are then supposed to have been generated by numpy.mgrid, in other words, they are 3D arrays, with positions lying on a 3D orthogonal and regularly spaced grid with nearest neighbor in space matching nearest neighbor in the array. The function builds a scalar field assuming the points are regularly spaced.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

contours:

Integer/list specifying number/list of contours. Specifying a list of values will only give the requested contours asked for.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_contour3d():
x, y, z = np.ogrid[-5:5:64j, -5:5:64j, -5:5:64j]

scalars = x * x * 0.5 + y * y + z * z * 2.0

obj = contour3d(scalars, contours=4, transparent=True)
return obj
```

## contour_surf¶

mayavi.mlab.contour_surf(*args, **kwargs)

Plots a the contours of a surface using grid-spaced data for elevation supplied as a 2D array.

Function signatures:

```contour_surf(s, ...)
contour_surf(x, y, s, ...)
contour_surf(x, y, f, ...)
```

s is the elevation matrix, a 2D array. The contour lines plotted are lines of equal s value.

x and y can be 1D or 2D arrays (such as returned by numpy.ogrid or numpy.mgrid), but the points should be located on an orthogonal grid (possibly non-uniform). In other words, all the points sharing a same index in the s array need to have the same x or y value. For arbitrary-shaped position arrays (non-orthogonal grids), see the mesh function.

If only 1 array s is passed, the x and y arrays are assumed to be made from the indices of arrays, and an uniformly-spaced data set is created.

If 3 positional arguments are passed the last one must be an array s, or a callable, f, that returns an array. x and y give the coordinates of positions corresponding to the s values.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

contours:

Integer/list specifying number/list of contours. Specifying a list of values will only give the requested contours asked for.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

warp_scale:

scale of the warp scalar

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_contour_surf():
"""Test contour_surf on regularly spaced co-ordinates like MayaVi."""
def f(x, y):
sin, cos = np.sin, np.cos
return sin(x + y) + sin(2 * x - y) + cos(3 * x + 4 * y)

x, y = np.mgrid[-7.:7.05:0.1, -5.:5.05:0.05]
s = contour_surf(x, y, f)
return s
```

## flow¶

mayavi.mlab.flow(*args, **kwargs)

Creates a trajectory of particles following the flow of a vector field.

Function signatures:

```flow(u, v, w, ...)
flow(x, y, z, u, v, w, ...)
flow(x, y, z, f, ...)
```

u, v, w are numpy arrays giving the components of the vectors.

If only 3 arrays, u, v, and w are passed, they must be 3D arrays, and the positions of the arrows are assumed to be the indices of the corresponding points in the (u, v, w) arrays.

If 6 arrays, (x, y, z, u, v, w) are passed, the 3 first arrays give the position of the arrows, and the 3 last the components. The x, y and z arrays are then supposed to have been generated by numpy.mgrid, in other words, they are 3D arrays, with positions lying on a 3D orthogonal and regularly spaced grid with nearest neighbor in space matching nearest neighbor in the array. The function builds a vector field assuming the points are regularly spaced.

If 4 positional arguments, (x, y, z, f) are passed, the last one must be a callable, f, that returns vectors components (u, v, w) given the positions (x, y, z).

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

integration_direction:

The direction of the integration. Must be ‘forward’ or ‘backward’ or ‘both’. Default: forward

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

linetype:

the type of line-like object used to display the streamline. Must be ‘line’ or ‘ribbon’ or ‘tube’. Default: line

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

scalars:

optional scalar data.

seed_resolution:

The resolution of the seed. Determines the number of seed points Must be an integer or None.

seed_scale:

Scales the seed around its default center Must be a float. Default: 1.0

seed_visible:

Control the visibility of the seed. Must be a boolean. Default: True

seedtype:

the widget used as a seed for the streamlines. Must be ‘line’ or ‘plane’ or ‘point’ or ‘sphere’. Default: sphere

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_flow():
x, y, z = np.mgrid[-4:4:40j, -4:4:40j, 0:4:20j]
r = np.sqrt(x ** 2 + y ** 2 + z ** 2 + 0.1)
u = y * np.sin(r) / r
v = -x * np.sin(r) / r
w = np.ones_like(z)*0.05
obj = flow(u, v, w)
return obj
```

## imshow¶

mayavi.mlab.imshow(*args, **kwargs)

View a 2D array as an image.

Function signatures:

```imshow(s, ...)
```

s is a 2 dimension array. The values of s are mapped to a color using the colormap.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

interpolate:

if the pixels in the image are to be interpolated or not. Must be a boolean. Default: True

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

name:

the name of the vtk object created.

opacity:

the opacity of the image. Must be a legal value. Default: 1.0

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_imshow():
""" Use imshow to visualize a 2D 10x10 random array.
"""
s = np.random.random((10, 10))
return imshow(s, colormap='gist_earth')
```

## mesh¶

mayavi.mlab.mesh(*args, **kwargs)

Plots a surface using grid-spaced data supplied as 2D arrays.

Function signatures:

```mesh(x, y, z, ...)
```

x, y, z are 2D arrays, all of the same shape, giving the positions of the vertices of the surface. The connectivity between these points is implied by the connectivity on the arrays.

For simple structures (such as orthogonal grids) prefer the surf function, as it will create more efficient data structures. For mesh defined by triangles rather than regular implicit connectivity, see the triangular_mesh function.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

boolean mask array to suppress some data points. Note: this works based on colormapping of scalars and will not work if you specify a solid color using the color keyword.

If supplied, only one out of ‘mask_points’ data point is displayed. This option is useful to reduce the number of points displayed on large datasets Must be an integer or None.

mode:

the mode of the glyphs. Must be ‘2darrow’ or ‘2dcircle’ or ‘2dcross’ or ‘2ddash’ or ‘2ddiamond’ or ‘2dhooked_arrow’ or ‘2dsquare’ or ‘2dthick_arrow’ or ‘2dthick_cross’ or ‘2dtriangle’ or ‘2dvertex’ or ‘arrow’ or ‘axes’ or ‘cone’ or ‘cube’ or ‘cylinder’ or ‘point’ or ‘sphere’. Default: sphere

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

representation:

the representation type used for the surface. Must be ‘surface’ or ‘wireframe’ or ‘points’ or ‘mesh’ or ‘fancymesh’. Default: surface

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

resolution:

The resolution of the glyph created. For spheres, for instance, this is the number of divisions along theta and phi. Must be an integer. Default: 8

scalars:

optional scalar data.

scale_factor:

scale factor of the glyphs used to represent the vertices, in fancy_mesh mode. Must be a float. Default: 0.05

scale_mode:

the scaling mode for the glyphs (‘vector’, ‘scalar’, or ‘none’).

transparent:

make the opacity of the actor depend on the scalar.

radius of the tubes used to represent the lines, in mesh mode. If None, simple lines are used.

tube_sides:

number of sides of the tubes used to represent the lines. Must be an integer. Default: 6

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_mesh():
"""A very pretty picture of spherical harmonics translated from
the octaviz example."""
pi = np.pi
cos = np.cos
sin = np.sin
dphi, dtheta = pi / 250.0, pi / 250.0
[phi, theta] = np.mgrid[0:pi + dphi * 1.5:dphi,
0:2 * pi + dtheta * 1.5:dtheta]
m0 = 4
m1 = 3
m2 = 2
m3 = 3
m4 = 6
m5 = 2
m6 = 6
m7 = 4
r = sin(m0 * phi) ** m1 + cos(m2 * phi) ** m3 + \
sin(m4 * theta) ** m5 + cos(m6 * theta) ** m7
x = r * sin(phi) * cos(theta)
y = r * cos(phi)
z = r * sin(phi) * sin(theta)

return mesh(x, y, z, colormap="bone")
```

## plot3d¶

mayavi.mlab.plot3d(*args, **kwargs)

Draws lines between points.

Function signatures:

```plot3d(x, y, z, ...)
plot3d(x, y, z, s, ...)
```

x, y, z and s are numpy arrays or lists of the same shape. x, y and z give the positions of the successive points of the line. s is an optional scalar value associated with each point.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

representation:

the representation type used for the surface. Must be ‘surface’ or ‘wireframe’ or ‘points’. Default: surface

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

transparent:

make the opacity of the actor depend on the scalar.

radius of the tubes used to represent the lines, If None, simple lines are used.

tube_sides:

number of sides of the tubes used to represent the lines. Must be an integer. Default: 6

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_plot3d():
"""Generates a pretty set of lines."""
n_mer, n_long = 6, 11
dphi = np.pi / 1000.0
phi = np.arange(0.0, 2 * np.pi + 0.5 * dphi, dphi)
mu = phi * n_mer
x = np.cos(mu) * (1 + np.cos(n_long * mu / n_mer) * 0.5)
y = np.sin(mu) * (1 + np.cos(n_long * mu / n_mer) * 0.5)
z = np.sin(n_long * mu / n_mer) * 0.5

l = plot3d(x, y, z, np.sin(mu), tube_radius=0.025, colormap='Spectral')
return l
```

## points3d¶

mayavi.mlab.points3d(*args, **kwargs)

Plots glyphs (like points) at the position of the supplied data.

Function signatures:

```points3d(x, y, z...)
points3d(x, y, z, s, ...)
points3d(x, y, z, f, ...)
```

x, y and z are numpy arrays, or lists, all of the same shape, giving the positions of the points.

If only 3 arrays x, y, z are given, all the points are drawn with the same size and color.

In addition, you can pass a fourth array s of the same shape as x, y, and z giving an associated scalar value for each point, or a function f(x, y, z) returning the scalar value. This scalar value can be used to modulate the color and the size of the points.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

If supplied, only one out of ‘mask_points’ data point is displayed. This option is useful to reduce the number of points displayed on large datasets Must be an integer or None.

mode:

the mode of the glyphs. Must be ‘2darrow’ or ‘2dcircle’ or ‘2dcross’ or ‘2ddash’ or ‘2ddiamond’ or ‘2dhooked_arrow’ or ‘2dsquare’ or ‘2dthick_arrow’ or ‘2dthick_cross’ or ‘2dtriangle’ or ‘2dvertex’ or ‘arrow’ or ‘axes’ or ‘cone’ or ‘cube’ or ‘cylinder’ or ‘point’ or ‘sphere’. Default: sphere

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

resolution:

The resolution of the glyph created. For spheres, for instance, this is the number of divisions along theta and phi. Must be an integer. Default: 8

scale_factor:

The scaling applied to the glyphs. the size of the glyph is by default calculated from the inter-glyph spacing. Specify a float to give the maximum glyph size in drawing units

scale_mode:

the scaling mode for the glyphs (‘vector’, ‘scalar’, or ‘none’).

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_points3d():
t = np.linspace(0, 4 * np.pi, 20)

x = np.sin(2 * t)
y = np.cos(t)
z = np.cos(2 * t)
s = 2 + np.sin(t)

return points3d(x, y, z, s, colormap="copper", scale_factor=.25)
```

## quiver3d¶

mayavi.mlab.quiver3d(*args, **kwargs)

Plots glyphs (like arrows) indicating the direction of the vectors at the positions supplied.

Function signatures:

```quiver3d(u, v, w, ...)
quiver3d(x, y, z, u, v, w, ...)
quiver3d(x, y, z, f, ...)
```

u, v, w are numpy arrays giving the components of the vectors.

If only 3 arrays, u, v, and w are passed, they must be 3D arrays, and the positions of the arrows are assumed to be the indices of the corresponding points in the (u, v, w) arrays.

If 6 arrays, (x, y, z, u, v, w) are passed, the 3 first arrays give the position of the arrows, and the 3 last the components. They can be of any shape.

If 4 positional arguments, (x, y, z, f) are passed, the last one must be a callable, f, that returns vectors components (u, v, w) given the positions (x, y, z).

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

If supplied, only one out of ‘mask_points’ data point is displayed. This option is useful to reduce the number of points displayed on large datasets Must be an integer or None.

mode:

the mode of the glyphs. Must be ‘2darrow’ or ‘2dcircle’ or ‘2dcross’ or ‘2ddash’ or ‘2ddiamond’ or ‘2dhooked_arrow’ or ‘2dsquare’ or ‘2dthick_arrow’ or ‘2dthick_cross’ or ‘2dtriangle’ or ‘2dvertex’ or ‘arrow’ or ‘axes’ or ‘cone’ or ‘cube’ or ‘cylinder’ or ‘point’ or ‘sphere’. Default: 2darrow

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

resolution:

The resolution of the glyph created. For spheres, for instance, this is the number of divisions along theta and phi. Must be an integer. Default: 8

scalars:

optional scalar data.

scale_factor:

The scaling applied to the glyphs. the size of the glyph is by default calculated from the inter-glyph spacing. Specify a float to give the maximum glyph size in drawing units

scale_mode:

the scaling mode for the glyphs (‘vector’, ‘scalar’, or ‘none’).

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_quiver3d():
x, y, z = np.mgrid[-2:3, -2:3, -2:3]
r = np.sqrt(x ** 2 + y ** 2 + z ** 4)
u = y * np.sin(r) / (r + 0.001)
v = -x * np.sin(r) / (r + 0.001)
w = np.zeros_like(z)
obj = quiver3d(x, y, z, u, v, w, line_width=3, scale_factor=1)
return obj
```

## set_picker_props¶

mayavi.mlab.set_picker_props(figure=None, pick_type='point_picker', tolerance=0.025, text_color=None)

## surf¶

mayavi.mlab.surf(*args, **kwargs)

Plots a surface using regularly-spaced elevation data supplied as a 2D array.

Function signatures:

```surf(s, ...)
surf(x, y, s, ...)
surf(x, y, f, ...)
```

s is the elevation matrix, a 2D array, where indices along the first array axis represent x locations, and indices along the second array axis represent y locations.

x and y can be 1D or 2D arrays such as returned by numpy.ogrid or numpy.mgrid. Arrays returned by numpy.meshgrid require a transpose first to obtain correct indexing order. The points should be located on an orthogonal grid (possibly non-uniform). In other words, all the points sharing a same index in the s array need to have the same x or y value. For arbitrary-shaped position arrays (non-orthogonal grids), see the mesh function.

If only 1 array s is passed, the x and y arrays are assumed to be made from the indices of arrays, and an uniformly-spaced data set is created.

If 3 positional arguments are passed the last one must be an array s, or a callable, f, that returns an array. x and y give the coordinates of positions corresponding to the s values.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

boolean mask array to suppress some data points. Note: this works based on colormapping of scalars and will not work if you specify a solid color using the color keyword.

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

representation:

the representation type used for the surface. Must be ‘surface’ or ‘wireframe’ or ‘points’. Default: surface

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

warp_scale:

scale of the z axis (warped from the value of the scalar). By default this scale is a float value. If you specify ‘auto’, the scale is calculated to give a pleasant aspect ratio to the plot, whatever the bounds of the data. If you specify a value for warp_scale in addition to an extent, the warp scale will be determined by the warp_scale, and the plot be positioned along the z axis with the zero of the data centered on the center of the extent. If you are using explicit extents, this is the best way to control the vertical scale of your plots. If you want to control the extent (or range) of the surface object, rather than its scale, see the extent keyword argument.

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_surf():
"""Test surf on regularly spaced co-ordinates like MayaVi."""
def f(x, y):
sin, cos = np.sin, np.cos
return sin(x + y) + sin(2 * x - y) + cos(3 * x + 4 * y)

x, y = np.mgrid[-7.:7.05:0.1, -5.:5.05:0.05]
s = surf(x, y, f)
#cs = contour_surf(x, y, f, contour_z=0)
return s
```

## triangular_mesh¶

mayavi.mlab.triangular_mesh(*args, **kwargs)

Plots a surface using a mesh defined by the position of its vertices and the triangles connecting them.

Function signatures:

```triangular_mesh(x, y, z, triangles ...)
```

x, y, z are arrays giving the positions of the vertices of the surface. triangles is a list of triplets (or an array) list the vertices in each triangle. Vertices are indexes by their appearance number in the position arrays.

For simple structures (such as rectangular grids) prefer the surf or mesh functions, as they will create more efficient data structures.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

boolean mask array to suppress some data points. Note: this works based on colormapping of scalars and will not work if you specify a solid color using the color keyword.

If supplied, only one out of ‘mask_points’ data point is displayed. This option is useful to reduce the number of points displayed on large datasets Must be an integer or None.

mode:

the mode of the glyphs. Must be ‘2darrow’ or ‘2dcircle’ or ‘2dcross’ or ‘2ddash’ or ‘2ddiamond’ or ‘2dhooked_arrow’ or ‘2dsquare’ or ‘2dthick_arrow’ or ‘2dthick_cross’ or ‘2dtriangle’ or ‘2dvertex’ or ‘arrow’ or ‘axes’ or ‘cone’ or ‘cube’ or ‘cylinder’ or ‘point’ or ‘sphere’. Default: sphere

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

representation:

the representation type used for the surface. Must be ‘surface’ or ‘wireframe’ or ‘points’ or ‘mesh’ or ‘fancymesh’. Default: surface

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

resolution:

The resolution of the glyph created. For spheres, for instance, this is the number of divisions along theta and phi. Must be an integer. Default: 8

scalars:

optional scalar data.

scale_factor:

scale factor of the glyphs used to represent the vertices, in fancy_mesh mode. Must be a float. Default: 0.05

scale_mode:

the scaling mode for the glyphs (‘vector’, ‘scalar’, or ‘none’).

transparent:

make the opacity of the actor depend on the scalar.

radius of the tubes used to represent the lines, in mesh mode. If None, simple lines are used.

tube_sides:

number of sides of the tubes used to represent the lines. Must be an integer. Default: 6

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_triangular_mesh():
"""An example of a cone, ie a non-regular mesh defined by its
triangles.
"""
n = 8
t = np.linspace(-np.pi, np.pi, n)
z = np.exp(1j * t)
x = z.real.copy()
y = z.imag.copy()
z = np.zeros_like(x)

triangles = [(0, i, i + 1) for i in range(1, n)]
x = np.r_[0, x]
y = np.r_[0, y]
z = np.r_[1, z]
t = np.r_[0, t]

return triangular_mesh(x, y, z, triangles, scalars=t)
```

## volume_slice¶

mayavi.mlab.volume_slice(*args, **kwargs)

Plots an interactive image plane sliced through a 3D volume of data supplied as argument.

Function signatures:

```volume_slice(scalars, ...)
volume_slice(x, y, z, scalars, ...)
```

scalars is a 3D numpy arrays giving the data on a grid.

If 4 arrays, (x, y, z, scalars) are passed, the 3 first arrays give the position, and the last the scalar value. The x, y and z arrays are then supposed to have been generated by numpy.mgrid, in other words, they are 3D arrays, with positions lying on a 3D orthogonal and regularly spaced grid with nearest neighbor in space matching nearest neighbor in the array. The function builds a scalar field assuming the points are regularly spaced.

Keyword arguments:

color:

the color of the vtk object. Overides the colormap, if any, when specified. This is specified as a triplet of float ranging from 0 to 1, eg (1, 1, 1) for white.

colormap:

type of colormap to use.

extent:

[xmin, xmax, ymin, ymax, zmin, zmax] Default is the x, y, z arrays extent. Use this to change the extent of the object created.

figure:

Figure to populate.

line_width:

The width of the lines, if any used. Must be a float. Default: 2.0

name:

the name of the vtk object created.

opacity:

The overall opacity of the vtk object. Must be a float. Default: 1.0

plane_opacity:

the opacity of the plane actor. Must be a legal value. Default: 1.0

plane_orientation:

the orientation of the plane Must be a legal value. Default: x_axes

reset_zoom:

Reset the zoom to accomodate the data newly added to the scene. Defaults to True.

slice_index:

The index along with the image is sliced.

transparent:

make the opacity of the actor depend on the scalar.

vmax:

vmax is used to scale the colormap. If None, the max of the data will be used

vmin:

vmin is used to scale the colormap. If None, the min of the data will be used

Example (run in `ipython --gui=qt`, or in the mayavi2 interactive shell, see Running mlab scripts for more info):

```import numpy
from mayavi.mlab import *

def test_volume_slice():
x, y, z = np.ogrid[-5:5:64j, -5:5:64j, -5:5:64j]

scalars = x * x * 0.5 + y * y + z * z * 2.0

obj = volume_slice(scalars, plane_orientation='x_axes')
return obj
```