Python download_crater_topo Examples

Example #1

File: app.py Project: ziepakker/dash-sample-apps

import numpy as np
import pyvista as pv
from pyvista import examples
from vtk.util.numpy_support import vtk_to_numpy

from dash_vtk.utils import presets

random.seed(42)


def toDropOption(name):
    return {"label": name, "value": name}


# Get point cloud data from PyVista
uniformGrid = examples.download_crater_topo()
subset = uniformGrid.extract_subset((500, 900, 400, 800, 0, 0), (5, 5, 1))


def updateWarp(factor=1):
    terrain = subset.warp_by_scalar(factor=factor)
    polydata = terrain.extract_geometry()
    points = polydata.points.ravel()
    polys = vtk_to_numpy(polydata.GetPolys().GetData())
    elevation = polydata["scalar1of1"]
    min_elevation = np.amin(elevation)
    max_elevation = np.amax(elevation)
    return [points, polys, elevation, [min_elevation, max_elevation]]


points, polys, elevation, color_range = updateWarp(1)

Example #2

In this example, we demonstrate a simple way to make a 3D grid/mesh that
follows a given topographic surface. In this example, it is important to note
that the given digital elevation model (DEM) is structured (gridded and not
triangulated): this is common for DEMs.
"""

import numpy as np

# sphinx_gallery_thumbnail_number = 3
import pyvista as pv
from pyvista import examples

###############################################################################
# Download a gridded topography surface (DEM)
dem = examples.download_crater_topo()
dem

###############################################################################
# Now let's subsample and extract an area of interest to make this example
# simple (also the DEM we just load is pretty big).
# Since the DEM we loaded is a :class:`pyvista.UniformGrid` mesh, we can use
# the :func:`pyvista.UniformGridFilters.extract_subset` filter:
subset = dem.extract_subset((500, 900, 400, 800, 0, 0), (5, 5, 1))
subset.plot(cpos="xy")

###############################################################################
# Now that we have a region of interest for our terrain following mesh, lets
# make a 3D surface of that DEM:
terrain = subset.warp_by_scalar()
terrain

Example #3

"""
Topographic Map
~~~~~~~~~~~~~~~

This is very similar to the :ref:`ref_texture_example` example except it is
focused on plotting aerial imagery from a GeoTIFF on top of some topagraphy
mesh.
"""
# sphinx_gallery_thumbnail_number = 4

import pyvista as pv
from pyvista import examples

# Load the elevation data as a surface
elevation = examples.download_crater_topo().warp_by_scalar()
# Load the topographic map from a GeoTiff
topo_map = examples.download_crater_imagery()

elevation

###############################################################################
# Let's inspect the imagery that we just loaded
import matplotlib.pyplot as plt
import matplotlib as mpl
mpl.rcParams['figure.dpi'] = 500

plt.imshow(topo_map.to_array())

###############################################################################
# Once you have a topography mesh loaded as a surface mesh
# (we use a :class:`pyvista.StructuredGrid` here) and an image loaded as a