Hi, Im new to here. I wanted to ask for assitance in plotting ellipsoids onto XYZ plots based on Excel data. The data shows details for seismic events but the analysis needs to be just looking into the data as points on a XYZ graph. I have no experience with Matlab and any help would be greatly appreciated.

The first column is to identify the point; Column B is the time of the event; Column C-E is the location of the point. Column D reflects the amount of energy released. Colums G-R are for eigenvalues and eigenvectors.

Each ellipsoid is described by the 3 semi-major axes, named 1, 2, 3 in our file.

The 3 columns Axis 1, Axis 2, Axis 3 are the length (eigenvalues) of the 3 semi-major axis in metres.

The next 9 columns define the semi-major axis vectors (eigenvectors), so for example [Vector 1 X, Vector 1 Y, Vector 1 Z] define the 3 direction cosines (XYZ) of the Axis 1 vector.

So for example:

Axis 1 of the ellipsoid for Trigger ID 1 (screenshot below) has half-length 61m. It has vector orientation [-0.97, -0.06, 0.25], which can be imagined as a 3D line between point [0,0,0] and [-0.97, -0.6, 0.25].

I want to see if its possible to write something to convert them into XYZ points on an ellipsoid surface.

Or Find the Max value for Axis 1, Axis 2, Axis 3 – which tells you the maximum location uncertainty in metres for each event. This will normally be Axis 3.

If you then look at Vector 3 Z it will usually be close to +1.0 or -1.0 (which are the maximum and minimum values). If it is close to +/- 1.0 it means that the axis is near vertical. If it is close to 0.0 then it is horizontal.

Surface monitoring networks normally have the greatest location uncertainty in depth.

These specific eigenvectors mean:

[X=0.0, Y=+/-1.0, Z=0.0] would be North/South (ie: the Y component is largest).

[X=+/-1.0, Y=0.0, Z=0.0] would be East/West (ie: X biggest)

[X=0.0, Y=0.0, Z=+/-1.0] would be vertical

I have 600+ rows and the aim is to look at the elliposids to make interpretations on there orientation and their distrubtion. Thank you for any help.