# Ready-Made Plots

Some plots are the same in every lab: the newest spectrum, all spectra of a scan as a
map, one value against another. `plesty.lib.monitor.common` has them, so an
experiment that needs only these writes no plot of its own:

```python
from plesty.lib.monitor import Viz
from plesty.lib.monitor.common import Series, Spectrum, SpectrumMap

viz = Viz("Polarization PL", experiment="pol_pl", reads=read_spectrum)
viz.add_plot(Spectrum(weight=3))
viz.add_plot(SpectrumMap(row="hwp_deg", y_label="HWP angle (deg)", weight=3))
viz.add_plot(Series("power_w", x="hwp_deg", y_label="Power (W)"))
```

`read_spectrum` turns each row's spectrum file into `wavelength` and `counts` fields;
see [`reads`: rows that name a file](run_data.md#reads-rows-that-name-a-file).

Each is told which **fields** of the rows to use, so the names in your records are
up to you.

## `Spectrum`

The newest spectrum the run has saved, as a line.

| Argument | Default | Meaning |
|---|---|---|
| `y` | `"counts"` | the field holding the values |
| `x` | `"wavelength"` | the field holding the axis; without it, the samples are numbered |
| `x_label`, `y_label` | `"Wavelength (nm)"`, `"Counts"` | the axis labels |

## `SpectrumMap`

Every spectrum so far, stacked into an image against what was scanned. It uses a
square-root colour scale by default, because emission lines can differ in brightness
by more than ten times, and on a linear scale the weak ones disappear into the
background.

| Argument | Default | Meaning |
|---|---|---|
| `values` | `"counts"` | the field holding each spectrum |
| `row` | none | the field that was scanned, such as an angle; without it, the rows are numbered |
| `x` | `"wavelength"` | the field holding the axis |
| `scale` | `"sqrt"` | `"sqrt"` or `"linear"` |
| `x_label`, `y_label` | `"Wavelength (nm)"`, the `row` field (`"Row"` without one) | the axis labels |

To map something you have cleaned up first, such as the spectra with cosmic rays
removed, subclass `SpectrumMap` and override `block(data)`, which returns the 2-D
array to draw.

## `Series`

One field against another, one point per row.

| Argument | Default | Meaning |
|---|---|---|
| `y` | required | the field holding the value |
| `x` | none | the field holding the position; without it, the rows are numbered |
| `marker` | `True` | draw a marker on each point |
| `x_label`, `y_label` | the field names (`"Step"` without `x`) | the axis labels |

## Arguments they all take

`title`, `name` and `weight` mean the same as for `@viz.plot` (see
[A viewer](viz.md#a-viewer)), and `color` is a palette name (see
[The drawables](plots.md#the-drawables)).

Each is an ordinary `Plot`: to change one, subclass it, or write your own plot
instead (see [Three ways to write a plot](plots.md#three-ways-to-write-a-plot)).