__all__ = [
'OutlineContinents',
'GlobeSource',
]
import numpy as np
import pyvista as pv
import vtk
from .. import interface
from ..base import AlgorithmBase
class OutlineContinents(AlgorithmBase):
"""A simple data source to produce a ``vtkEarthSource`` outlining the
Earth's continents. This works well with our ``GlobeSource``.
"""
__displayname__ = 'Outline Continents'
__category__ = 'source'
def __init__(self, radius=6371.0e6):
AlgorithmBase.__init__(self,
nInputPorts=0,
nOutputPorts=1, outputType='vtkPolyData')
self.__radius = radius
def RequestData(self, request, inInfo, outInfo):
"""Used by pipeline to generate the output"""
pdo = self.GetOutputData(outInfo, 0)
earth = vtk.vtkEarthSource()
earth.SetRadius(self.__radius)
earth.OutlineOn()
earth.Update()
foo = pv.wrap(earth.GetOutput())
# Copy the geometries only
continents = pv.PolyData()
continents.points = foo.points.copy()
continents.lines = foo.lines.copy()
del foo
pdo.ShallowCopy(continents)
return 1
def set_radius(self, radius):
"""Set the radius of the globe. Defualt is 6.371.0e9 meters"""
if self.__radius != radius:
self.__radius = radius
self.Modified()
###############################################################################
class GlobeSource(AlgorithmBase):
"""Creates a globe/sphere the size of the Earth with texture coordinates
already mapped. The globe's center is assumed to be (0,0,0).
Args:
radius (float): the radius to use
npar (int): the number of parallels (latitude)
nmer (int): the number of meridians (longitude)
"""
__displayname__ = 'Globe Source'
__category__ = 'source'
def __init__(self, radius=6371.0e6, npar=15, nmer=36, **kwargs):
AlgorithmBase.__init__(self, nInputPorts=0, nOutputPorts=1, outputType='vtkPolyData')
self.__radius = radius
self.__npar = npar
self.__nmer = nmer
# TODO: use **kwargs
def spherical_to_cartesian(self, meridian, parallel):
"""Converts longitude/latitude to catesian coordinates. Assumes the
arguments are given in degrees.
"""
lon_r = np.radians(meridian)
lat_r = np.radians(parallel)
x = self.__radius * np.cos(lat_r) * np.cos(lon_r)
y = self.__radius * np.cos(lat_r) * np.sin(lon_r)
z = self.__radius * np.sin(lat_r)
return np.vstack((x, y, z)).T
def create_sphere(self):
"""Creates longitude/latitude as 2D points and returns the corresponding
texture coordinates for those positions."""
lon = np.linspace(-180.0, 180.0, self.__nmer)
lat = np.linspace(-90.0, 90.0, self.__npar)
lon_g, lat_g = np.meshgrid(lon, lat, indexing='ij')
pos = np.vstack([lon_g.ravel(), lat_g.ravel()]).T
# Now create the texture map
tcgx, tcgy = np.meshgrid(
np.linspace(0.0, 1.0, len(lon)),
np.linspace(0.0, 1.0, len(lat)),
indexing='ij')
tex = np.vstack([tcgx.ravel(), tcgy.ravel()]).T
return pos, tex
def build_globe(self):
"""Generates the globe as ``vtkPolyData``"""
# NOTE: https://gitlab.kitware.com/paraview/paraview/issues/19417
from scipy.spatial import Delaunay
pos, tex = self.create_sphere()
pts = self.spherical_to_cartesian(pos[:,0], pos[:,1])
points = interface.points_to_poly_data(pts).GetPoints()
texcoords = interface.convert_array(tex, name='Texture Coordinates')
# Now generate triangles
cell_connectivity = Delaunay(pos).simplices.astype(int)
cells = vtk.vtkCellArray()
cells.SetNumberOfCells(cell_connectivity.shape[0])
cells.SetCells(cell_connectivity.shape[0], interface.convert_cell_conn(cell_connectivity))
# Generate output
output = vtk.vtkPolyData()
output.SetPoints(points)
output.GetPointData().SetTCoords(texcoords)
output.SetPolys(cells)
return output
def RequestData(self, request, inInfo, outInfo):
"""The pipeline executes this to generate output"""
pdo = self.GetOutputData(outInfo, 0)
globe = self.build_globe()
pdo.ShallowCopy(globe)
return 1
def set_radius(self, radius):
"""Set the radius of the globe. Defualt is 6.371.0e9 meters"""
if self.__radius != radius:
self.__radius = radius
self.Modified()
def set_n_meridians(self, n):
"""Set the number of meridians to use"""
if self.__nmer != n:
self.__nmer = n
self.Modified()
def set_n_parallels(self, n):
"""Set the number of parallels to use"""
if self.__npar != n:
self.__npar = n
self.Modified()
