I use sympy plotting backends library to create plots directly from sympy expressions. As backends i use matplotlib library. Actually, i don't need to show a plot. I create plot and then i return it as svg string in order to insert it in a web page later. Everything worked fine, but when i started to use new virtual environment (i installed all necessary packages) i got an error. I use the following code:
# create two plot: one from init_expr (sympy tree expression) and second from
# fourier_expr (sympy tree expression):
p1 = plot(
(init_expr, (var, left_bound, right_bound), label_1, line_color_1),
(fourier_expr, (var, left_bound, right_bound), label_2, line_color_2),
show = False)
# add axes decorations and legend:
p1.xlabel = var_name
p1.ylabel = "f(" + data.var_name + ")"
p1.legend = True
# buffer to write svg data:
f = io.StringIO()
# save plot in svg formate in buffer:
p1.save(f, format = "svg")
# return svg string:
return f.getvalue()
when execution begins, at line:
p1.save(f, format="svg")
i get an error:
AttributeError("'NoneType' object has no attribute 'runner'")
Any ideas what am i doing wrong?
Related
maybe you can help me out with a right comment or hint for my problem.
Pretty easy, I would like to plot a 2D slice vtp file (OpenFOAM) via matplotlib as tricontourf plot.
1.) Creating the vtp slice by Paraview and saving as vtp file works like a charme
2.) Using the runtime vtp file, created by cuttingPlane - libsampling OpenFOAM creates a weird triangle order.
What am I missing?
Best,
def loadVTPFile(filename):
import vtk
from vtk.util.numpy_support import vtk_to_numpy
from vtk.util import numpy_support as npvtk
reader = vtk.vtkXMLPolyDataReader()
reader.SetFileName(filename)
reader.Update()
data = reader.GetOutput()
points = data.GetPoints()
npts = points.GetNumberOfPoints()
x = vtk_to_numpy(points.GetData())
triangles= vtk_to_numpy(data.GetPolys().GetData())
ntri = triangles.size // 4 # number of cells
tri = np.take(triangles,[n for n in range(triangles.size) if n%4 != 0]).reshape(ntri,3)
n_arrays = reader.GetNumberOfPointArrays()
for i in range(n_arrays):
print(reader.GetPointArrayName(i))
X = vtk_to_numpy(points.GetData())
x=X[:,0]
y=X[:,1]
z=X[:,2]
# Define the velocity components U=(u,v,w)
U = vtk_to_numpy(data.GetPointData().GetArray('UMean'))
u = U[:,0]
v = U[:,1]
w = U[:,2]
magU=np.sqrt(u**2+v**2+w**2)
p = vtk_to_numpy(data.GetPointData().GetArray('pMean'))
Ma = vtk_to_numpy(data.GetPointData().GetArray('MaMean'))
rho = vtk_to_numpy(data.GetPointData().GetArray('rhoMean'))
return x,y,z,u,v,w,magU,p,Ma,rho,tri
1st: Paraview vtp slice via matplotlib:
Paraview vtp slice via matplotlib
2nd image OpenFOAM cut via libsampling
2nd image OpenFOAM cut via libsampling
Thanks for your help
OpenFOAM vtp slice export:
cellPoint, triangulated true/false, interpolated true/false and so on...
I am a newbie in OpenCV using Python. I am currently working with a project related opencv using python language. I have a video data set named "VideoDataSet/dynamicBackground/canoe/input" that stores the sequence of image frames and I would like to convert the sequence of frames from the file path to a video. However, I am getting an error when I execute the program. I have tried various codecs but it still gives me the same errors, can any of you please shed some light on what might be wrong? Thank you.
This is my sample code:
import cv2
import numpy as np
import os
import glob as gb
filename = "VideoDataSet/dynamicBackground/canoe/input"
img_path = gb.glob(filename)
videoWriter = cv2.VideoWriter('test.avi', cv2.VideoWriter_fourcc(*'MJPG'),
25, (640,480))
for path in img_path:
img = cv2.imread(path)
img = cv2.resize(img,(640,480))
videoWriter.write(img)
print ("you are success create.")
This is the error:
Error prompt out:cv2.error: OpenCV(3.4.1) D:\Build\OpenCV\opencv-3.4.1\modules\imgproc\src\resize.cpp:4044: error: (-215) ssize.width > 0 && ssize.height > 0 in function cv::resize
(Note: the problem occur with the img = cv2.resize(img,(640,480)))
It is returning this error because you are trying to re-size the directory entry! You need to put:
filename = "VideoDataSet/dynamicBackground/canoe/input/*"
So that it will match all the files in the folder when you glob it. The error actually suggested that the source image had either zero width or zero height. Putting:
print( img_path )
In after your glob attempt showed that it was only returning the directory entry itself.
You subsequently discovered that although it was now generating a file, it was corrupted. This is because you are incorrectly specifying the codec. Replace your fourcc parameter with this:
cv2.VideoWriter_fourcc('M','J','P','G')
you can try this:
img_path = gb.glob(filename)
videoWriter = cv2.VideoWriter('frame2video.avi', cv2.VideoWriter_fourcc(*'MJPG'), 25, (640,480))
for path in img_path:
img = cv2.imread(path)
img = cv2.resize(img,(640,480))
videoWriter.write(img)
I'm trying to extend the odo library with functionality to convert a GDAL dataset (raster with spatial information) to a NetCDF file.
Reading in the gdal dataset goes fine. But in the creation stage of the netcdf I need some metadata of the gdal dataset (metadata that is not know yet when calling odo.odo(source,target) ). How could I achieve this?
a short version of my code so far:
import odo
from odo import resource, append
import gdal
import netCDF4 as nc4
import numpy as np
#resource.register('.+\.tif')
def resource_gdal(uri, **kwargs):
ds = gdal.Open(uri)
# metadata I need to transfer to netcdf
b = ds.GetGeoTransform() #bbox, interval
return ds
#resource.register('.+\.nc')
def resource_netcdf(uri, dshape=None, **kwargs):
ds = nc4.Dataset(uri,'w')
# create lat lon dimensions and variables
ds.createDimension(lat, dshape[0].val)
ds.createDimension(lon, dshape[1].val)
lat = ds.createVariable('lat','f4', ('lat',))
lon = ds.createVariable('lon','f4', ('lon',))
# create a range from the **gdal metadata**
lat_array = np.arange(dshape[0].val)*b[1]+b[0]
lon_array = np.arange(dshape[1].val)*b[5]+b[3]
# assign the range to the netcdf variable
lat[:] = lat_array
lon[:] = lon_array
# create the variable which will hold the gdal data
data = ds.createVariable('data', 'f4', ('lat', 'lon',))
return data
#append.register(nc4.Variable, gdal.Dataset)
def append_gdal_to_nc4(tgt, src, **kwargs):
arr = src.ReadAsArray()
tgt[:] = arr
return tgt
Thanks!
I don't have much experience with odo, but from browsing the source code and docs it looks like resource_netcdf() should not be involved in translating gdal data to netcdf. Translating should be the job of a gdal_to_netcdf() function decorated by convert.register. In such a case, the gdal.Dataset object returned by resource_gdal would have all sufficient information (georeferencing, pixel size) to make a netcdf.
For those that want to export a simple 3D numpy array (along with axes) to a .vtk (or .vtr) file for post-processing and display in Paraview or Mayavi there's a little module called PyEVTK that does exactly that. The module supports structured and unstructured data etc..
Unfortunately, even though the code works fine in unix-based systems I couldn't make it work (keeps crashing) on any windows installation which simply makes things complicated. Ive contacted the developer but his suggestions did not work
Therefore my question is:
How can one use the from vtk.util import numpy_support function to export a 3D array (the function itself doesn't support 3D arrays) to a .vtk file? Is there a simple way to do it without creating vtkDatasets etc etc?
Thanks a lot!
It's been forever and I had entirely forgotten asking this question but I ended up figuring it out. I've written a post about it in my blog (PyScience) providing a tutorial on how to convert between NumPy and VTK. Do take a look if interested:
pyscience.wordpress.com/2014/09/06/numpy-to-vtk-converting-your-numpy-arrays-to-vtk-arrays-and-files/
It's not a direct answer to your question, but if you have tvtk (if you have mayavi, you should have it), you can use it to write your data to vtk format. (See: http://code.enthought.com/projects/files/ETS3_API/enthought.tvtk.misc.html )
It doesn't use PyEVTK, and it supports a broad range of data sources (more than just structured and unstructured grids), so it will probably work where other things aren't.
As a quick example (Mayavi's mlab interface can make this much less verbose, especially if you're already using it.):
import numpy as np
from enthought.tvtk.api import tvtk, write_data
data = np.random.random((10,10,10))
grid = tvtk.ImageData(spacing=(10, 5, -10), origin=(100, 350, 200),
dimensions=data.shape)
grid.point_data.scalars = np.ravel(order='F')
grid.point_data.scalars.name = 'Test Data'
# Writes legacy ".vtk" format if filename ends with "vtk", otherwise
# this will write data using the newer xml-based format.
write_data(grid, 'test.vtk')
And a portion of the output file:
# vtk DataFile Version 3.0
vtk output
ASCII
DATASET STRUCTURED_POINTS
DIMENSIONS 10 10 10
SPACING 10 5 -10
ORIGIN 100 350 200
POINT_DATA 1000
SCALARS Test%20Data double
LOOKUP_TABLE default
0.598189 0.228948 0.346975 0.948916 0.0109774 0.30281 0.643976 0.17398 0.374673
0.295613 0.664072 0.307974 0.802966 0.836823 0.827732 0.895217 0.104437 0.292796
0.604939 0.96141 0.0837524 0.498616 0.608173 0.446545 0.364019 0.222914 0.514992
...
...
TVTK of Mayavi has a beautiful way of writing vtk files. Here is a test example I have written for myself following #Joe and tvtk documentation. The advantage it has over evtk, is the support for both ascii and html.Hope it will help other people.
from tvtk.api import tvtk, write_data
import numpy as np
#data = np.random.random((3, 3, 3))
#
#i = tvtk.ImageData(spacing=(1, 1, 1), origin=(0, 0, 0))
#i.point_data.scalars = data.ravel()
#i.point_data.scalars.name = 'scalars'
#i.dimensions = data.shape
#
#w = tvtk.XMLImageDataWriter(input=i, file_name='spoints3d.vti')
#w.write()
points = np.array([[0,0,0], [1,0,0], [1,1,0], [0,1,0]], 'f')
(n1, n2) = points.shape
poly_edge = np.array([[0,1,2,3]])
print n1, n2
## Scalar Data
#temperature = np.array([10., 20., 30., 40.])
#pressure = np.random.rand(n1)
#
## Vector Data
#velocity = np.random.rand(n1,n2)
#force = np.random.rand(n1,n2)
#
##Tensor Data with
comp = 5
stress = np.random.rand(n1,comp)
#
#print stress.shape
## The TVTK dataset.
mesh = tvtk.PolyData(points=points, polys=poly_edge)
#
## Data 0 # scalar data
#mesh.point_data.scalars = temperature
#mesh.point_data.scalars.name = 'Temperature'
#
## Data 1 # additional scalar data
#mesh.point_data.add_array(pressure)
#mesh.point_data.get_array(1).name = 'Pressure'
#mesh.update()
#
## Data 2 # Vector data
#mesh.point_data.vectors = velocity
#mesh.point_data.vectors.name = 'Velocity'
#mesh.update()
#
## Data 3 additional vector data
#mesh.point_data.add_array( force)
#mesh.point_data.get_array(3).name = 'Force'
#mesh.update()
mesh.point_data.tensors = stress
mesh.point_data.tensors.name = 'Stress'
# Data 4 additional tensor Data
#mesh.point_data.add_array(stress)
#mesh.point_data.get_array(4).name = 'Stress'
#mesh.update()
write_data(mesh, 'polydata.vtk')
# XML format
# Method 1
#write_data(mesh, 'polydata')
# Method 2
#w = tvtk.XMLPolyDataWriter(input=mesh, file_name='polydata.vtk')
#w.write()
I know it is a bit late and I do love your tutorials #somada141. This should work too.
def numpy2VTK(img, spacing=[1.0, 1.0, 1.0]):
# evolved from code from Stou S.,
# on http://www.siafoo.net/snippet/314
# This function, as the name suggests, converts numpy array to VTK
importer = vtk.vtkImageImport()
img_data = img.astype('uint8')
img_string = img_data.tostring() # type short
dim = img.shape
importer.CopyImportVoidPointer(img_string, len(img_string))
importer.SetDataScalarType(VTK_UNSIGNED_CHAR)
importer.SetNumberOfScalarComponents(1)
extent = importer.GetDataExtent()
importer.SetDataExtent(extent[0], extent[0] + dim[2] - 1,
extent[2], extent[2] + dim[1] - 1,
extent[4], extent[4] + dim[0] - 1)
importer.SetWholeExtent(extent[0], extent[0] + dim[2] - 1,
extent[2], extent[2] + dim[1] - 1,
extent[4], extent[4] + dim[0] - 1)
importer.SetDataSpacing(spacing[0], spacing[1], spacing[2])
importer.SetDataOrigin(0, 0, 0)
return importer
Hope it helps!
Here's a SimpleITK version with the function load_itk taken from here:
import SimpleITK as sitk
import numpy as np
if len(sys.argv)<3:
print('Wrong number of arguments.', file=sys.stderr)
print('Usage: ' + __file__ + ' input_sitk_file' + ' output_sitk_file', file=sys.stderr)
sys.exit(1)
def quick_read(filename):
# Read image information without reading the bulk data.
file_reader = sitk.ImageFileReader()
file_reader.SetFileName(filename)
file_reader.ReadImageInformation()
print('image size: {0}\nimage spacing: {1}'.format(file_reader.GetSize(), file_reader.GetSpacing()))
# Some files have a rich meta-data dictionary (e.g. DICOM)
for key in file_reader.GetMetaDataKeys():
print(key + ': ' + file_reader.GetMetaData(key))
def load_itk(filename):
# Reads the image using SimpleITK
itkimage = sitk.ReadImage(filename)
# Convert the image to a numpy array first and then shuffle the dimensions to get axis in the order z,y,x
data = sitk.GetArrayFromImage(itkimage)
# Read the origin of the ct_scan, will be used to convert the coordinates from world to voxel and vice versa.
origin = np.array(list(reversed(itkimage.GetOrigin())))
# Read the spacing along each dimension
spacing = np.array(list(reversed(itkimage.GetSpacing())))
return data, origin, spacing
def convert(data, output_filename):
image = sitk.GetImageFromArray(data)
writer = sitk.ImageFileWriter()
writer.SetFileName(output_filename)
writer.Execute(image)
def wait():
print('Press Enter to load & convert or exit using Ctrl+C')
input()
quick_read(sys.argv[1])
print('-'*20)
wait()
data, origin, spacing = load_itk(sys.argv[1])
convert(sys.argv[2])
I want to know if it is possible to import data of attitude and position (roll/pitch/yaw & xyz) from a comma separated file to Blender?
I recorded data from a little RC car and I want to represent its movement in a 3D world.
I have timestamps too, so if there's a way to animated the movement of the object it'll be superb!!
Any help will be greatly appreciated!!
Best Regards.
A slight modifcation, making use of the csv module
import bpy
import csv
position_vectors = []
filepath = "C:\\Work\\position.log"
csvfile = open(filepath, 'r', newline='')
ofile = csv.reader(csvfile, delimiter=',')
for row in ofile:
position_vectors.append(tuple([float(i) for i in row]))
csvfile.close()
This will get your points into Blender. Note the delimiter parameter in csv.reader, change that accordingly. With a real example file of your RC car we could provide a more complete solution.
For blender v2.62:
If you have a file "positions.log" looking like:
-8.691985196313894e-002; 4.119284642631801e-001; -5.832147659661263e-001
1.037146774956164e+000; 8.137243553005405e-002; -5.703274929662892e-001
-3.602584527944123e-001; 8.378614512537046e-001; 2.615265921163826e-001
6.266465707681335e-001; -1.128416901202341e+000; -1.664644365541639e+000
3.327523280880091e-001; 4.488553740582839e-001; -2.449449085462368e+000
-7.311567199869298e-001; -1.860587923723032e+000; -1.297179602213110e+000
-7.453603745688361e-003; 4.770473577895327e-001; -2.319515785100494e+000
1.935170866863264e-001; -2.010280476717868e+000; 3.748000986190077e-001
5.201529166915653e-001; 3.952972788761738e-001; 1.658581747430548e+000
4.719198263774027e-001; 1.526020825619557e+000; 3.187088567866725e-002
you can read it with this python script in blender (watch out for the indentation!)
import bpy
from mathutils import *
from math import *
from bpy.props import *
import os
import time
# Init
position_vector = []
# Open file
file = open("C:\\Work\\position.log", "r")
# Loop over line in file
for line in file:
# Split line at ";"
splittet_line = line.split(";")
# Append new postion
position_vector.append(
Vector((float(splittet_line[0]),
float(splittet_line[1]),
float(splittet_line[2]))))
# Close file
file.close()
# Get first selected object
selected_object = bpy.context.selected_objects[0]
# Get first selected object
for position in position_vector:
selected_object.location = position
This reads the file and updates the position of the first selected object accordingly. Way forward: What you have to find out is how to set the keyframes for the animation...
Consider this python snippet to add to the solutions above
obj = bpy.context.object
temporalScale=bpy.context.scene.render.fps
for lrt in locRotArray:
obj.location = (lrt[0], lrt[1], lrt[2])
# radians, and do you want XYZ, or ZYX?
obj.rotation_euler = (lrt[3], lrt[4], lrt[5])
time = lrt[6]*temporalScale
obj.keyframe_insert(data_path="location", frame=time)
obj.keyframe_insert(data_path="rotation_euler", frame=time)
I haven't tested it, but it will probably work, and gets you started.
With a spice2xyzv file as input file. The script writed by "Mutant Bob" seems to work.
But the xyz velocity data are km/s not euler angles, I think, and the import does not work for the angles.
# Records are <jd> <x> <y> <z> <vel x> <vel y> <vel z>
# Time is a TDB Julian date
# Position in km
# Velocity in km/sec
2456921.49775 213928288.518 -446198013.001 -55595492.9135 6.9011736 15.130842 0.54325805
Is there a solution to get them in Blender? Should I convert velocity angle to euler, is that possible in fact?
I use this script :
import bpy
from mathutils import *
from math import *
from bpy.props import *
import os
import time
# Init
position_vector = []
# Open file
file = open("D:\\spice2xyzv\\export.xyzv", "r")
obj = bpy.context.object
temporalScale=bpy.context.scene.render.fps
for line in file:
# Split line at ";"
print("line = %s" % line)
line = line.replace("\n","")
locRotArray = line.split(" ")
print("locRotArray = %s" % locRotArray )
#for lrt in locRotArray:
print(locRotArray[1])
obj.location = (float(locRotArray[1]), float(locRotArray[2]), float(locRotArray[3]))
# radians, and do you want XYZ, or ZYX?
obj.rotation_euler = (float(locRotArray[4]), float(locRotArray[5]), float(locRotArray[5]))
time = float(locRotArray[0])*temporalScale
print("time = %s" % time)
obj.keyframe_insert(data_path="location", frame=time)
obj.keyframe_insert(data_path="rotation_euler", frame=time)