[vtkusers] structured points dataset

[Prabhu Ramachandran]

>>>>> "BA" == Beate Aistleitner <B.Aistleitner at irl.cri.nz> writes:

    BA> Hi, I have a some troubles understanding the syntax of a
    BA> structured points dataset and the input of scalar values. I
    BA> have 3D data where the origin of the axis is not 0 but the
    BA> range is for example from -3 to 4. The values are as for
    BA> example this one -3.254. I want to write this data into a .vtk
    BA> file and use the vtkSturcturedPointsReader for reading this
    BA> data into my program.  My problem now is how this file has to
    BA> look like exactly to fit the requirements for the
    BA> vtkStructuredPointsReader because the examples I found are
    BA> just like the following one.

The DIMENSIONS indicate how many values you have per axis.  So 
DIMENSIONS 10 10 30 
implies 10 along x, 10 along y and 30 along z.

ORIGIN specifies the starting point of your data set and SPACING
specifies the distance between two points along each axes.

The value after POINT_DATA is the number of points that you have in
your dataset in the above case it should be 3000.

Finally, remember that the POINT_DATA should be specified such that
the x co-ordinate varies fastest, y next and z last.

A trivial example:

# vtk DataFile Version 2.0
Structured points example.
ASCII
DATASET STRUCTURED_POINTS
DIMENSIONS 2 2 1
ORIGIN 0.0 0.0 0.0
SPACING 1.0 1.0 1.0

POINT_DATA 4
SCALARS Temperature float
LOOKUP_TABLE default
100 200
300 400

VECTORS velocity float
0.0 0.0 0.0
1.0 0.0 0.0
0.0 1.0 0.0
1.0 1.0 0.0


cheers,
prabhu