[vtk-developers] Structured Grid

[Alessandro Artusi]

Dear All,

What i want to do is the following:

- I am reading volume data from a netCDF file
- I want to compute the isosurfaces

I am able to do both of them using a rectilinear grid, so as I have the
isosurfaces on a rectilinear shape including the depth,
but when I try to map these data on a sphere (using conversion from
cartesian to spherical) using StructuredGrid and I visualise the result
seems that  the depth dissapear and I have as result a circle.

The code to map the latitude, longitude and depth to X,Y,Z for mapping to
sphere is the following:

# Convresion to spherical coordinates

E_Radius = 6370

gamma = 10

volume = empty(shape=(len(zc), len(xc), len(yc)), dtype=float32, order='C')

coordinates = array([0,0,0], dtype=int)

lats = xc.getValue()

longs = yc.getValue()

depths = zc.getValue()
# I generate a vtk Points data structure where to put the coordinates
points = vtk.vtkPoints()

points.Allocate(10, len(xc)*len(yc)*len(zc))
# I start the conversion of teh coordinates, the volume data are transfered
in a 3-D array
# the coordinates are in 1-D array with offset to relate the coordinate to
the volume pixel. I did
# also without this offset but the result si the same

for k in range(len(zc)):

   kOffset = k * len(xc) * len(yc)

   for i in range(len(xc)):

     iOffset = i * len(yc)

     for j in range(len(yc)):

       coordinates[0] = (E_Radius + gamma*k) * cos(lats[i]) * cos(longs[j])
# x

       coordinates[1]= (E_Radius + gamma*k) * cos(lats[i]) * sin(longs[j]) #
y

       coordinates[2] = (E_Radius + gamma*k) * sin(lats[i]) # z

       Offset = j + kOffset + iOffset

       points.InsertPoint(Offset,coordinates)

       volume[k,i,j] = var[0,k,i,j] # have also put the volume data in a 1-D
array indexing                                         # thedata with the
Offset but no way

array_data = nm_to_vtk_array(volume, float32)

result = vtk.vtkStructuredGrid()

result.SetDimensions(len(zc), len(xc), len(yc))

result.SetPoints(points)

result.GetPointData().SetScalars(array_data)

return result

i have no idea why not a sphere but a circle is coming out.
Any Help?

Thanks a lot,
Alessandro.
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