XY-sets
An XY-set is a set of two-dimensional curves. Mesh supports storing XY-sets in XY-set attributes, which can be versioned or unversioned. This document explains what XY-curves and XY-sets are, and how Mesh XY-set attributes are structured.
XY curves
An XY curve is a set of (x, y) pairs where x and y are 64 bit
floating point values.
| x | y |
|---|---|
| 1 | 2 |
| 2 | 1.5 |
| 3 | 0.5 |
| 10 | -1 |
An XY set is a set of XY curves, each curve indexed by a 64 bit floating point reference value. These reference values are sometimes called Z. We often visualize XY sets like so:
| x | z y |
z y |
|---|---|---|
| 0 | 180 | |
| 2 | 1.5 | 0.3 |
| 3 | 0.5 | 1 |
| 10 | -1 | 9 |
- The first non-header row contains the reference/Z values for that column.
- Usually the headers will have actual names, see further below.
A versioned XY set is a versioned list of XY sets. Each XY set in the list has a timestamp which indicates the start of the active period for that XY set, and the XY set is active until the next time-sorted XY set in the versioned XY set becomes active.
Mesh has attribute types for XY sets (XYSetAttribute) and versioned XY
sets (XYZSeriesAttribute). In the attribute definitions of those attributes
we store a description and a unit of measurement for each of X, Y, and Z. For
example if we have the following axis definitions...
| Axis | Description | Unit of measurement |
|---|---|---|
| X | Wind speed | m/s |
| Y | Production | MW |
| Z | Wind direction | degrees |
...Nimbus will visualize the above XY set as:
| Wind speed | Wind direction Production |
Wind direction Production |
|---|---|---|
| 0 | 180 | |
| 2 | 1.5 | 0.3 |
| 3 | 0.5 | 1 |
| 10 | -1 | 9 |