Characteristics of a dataset

As with all kinds of data, one of the first and most important steps is to get an overview of the resulting data and their characteristics. Furthermore, with a growing number of different measurements, keeping an overview is crucial. This is the realm of well-crafted, expressive graphical representations that are automatically generated, thus uniform and highly appropriate to compare different datasets and focus on their respective differences.

For tr-EPR data in particular, things get somewhat more complicated due to the two-dimensional nature of the data (magnetic field, time). One strategy to get a decent overview of the characteristics of a dataset would be:

  • Graphical overview of the entire dataset (2D plot),

  • Transients (slices along the time axis) at both, global maximum and global minimum, and

  • Spectra (slices along the magnetic field axis) at both, global maximum and global minimum.

Of course, prior to plotting, the usual corrections (pretrigger offset compensation, background correction) need to be applied.

Recipe

Complete recipe for creating a graphical representation consisting of three subpanels showing an overview of the entire dataset as 2D plot as well as transients and spectra at the global maximum and minimum, respectively. While automatically taking the global extrema might not always be the best idea, it is pretty useful for a first overview, at least as long as your data are not too noisy.
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format:
  type: ASpecD recipe
  version: '0.2'

settings:
  default_package: trepr
  autosave_plots: false

directories:
  datasets_source: ../../tests/testdata/fsc2/
  
datasets:
  #- radical-pair
  - triplet

tasks:
  - kind: processing
    type: PretriggerOffsetCompensation
    comment: >
        Compensate for DC offsets of the signal prior to the laser flash
  - kind: processing
    type: BackgroundCorrection
    comment: >
        Correct for laser-induced background signal.
  - kind: singleanalysis
    type: BasicCharacteristics
    properties:
      parameters:
        kind: max
        output: indices
        axis: 0
    result: max_field
    comment: Extract index of field axis for global maximum of the dataset
  - kind: singleanalysis
    type: BasicCharacteristics
    properties:
      parameters:
        kind: min
        output: indices
        axis: 0
    result: min_field
    comment: Extract index of field axis for global minimum of the dataset
  - kind: singleanalysis
    type: BasicCharacteristics
    properties:
      parameters:
        kind: max
        output: indices
        axis: 1
    result: max_time
    comment: Extract index of time axis for global maximum of the dataset
  - kind: singleanalysis
    type: BasicCharacteristics
    properties:
      parameters:
        kind: min
        output: indices
        axis: 1
    result: min_time
    comment: Extract index of time axis for global minimum of the dataset
  - kind: processing
    type: SliceExtraction
    properties:
      parameters:
        position: max_field
        axis: 0
    result: time_trace_max
    comment: Extract transient for global maximum of the dataset
  - kind: processing
    type: SliceExtraction
    properties:
      parameters:
        position: min_field
        axis: 0
    result: time_trace_min
    comment: Extract transient for global minimum of the dataset
  - kind: processing
    type: SliceExtraction
    properties:
      parameters:
        position: max_time
        axis: 1
    result: spectrum_max
    comment: Extract spectrum for global maximum of the dataset
  - kind: processing
    type: SliceExtraction
    properties:
      parameters:
        position: min_time
        axis: 1
    result: spectrum_min
    comment: Extract spectrum for global minimum of the dataset
  - kind: multiplot
    type: MultiPlotter1D
    properties:
      parameters:
        switch_axes: true
        tight_layout: true
        tight: y
      properties:
        grid:
          show: true
          axis: y
    apply_to:
    - time_trace_max
    - time_trace_min
    result: transients
  - kind: multiplot
    type: MultiPlotter1D
    properties:
      parameters:
        tight_layout: true
        tight: x
      properties:
        grid:
          show: true
          axis: x
    apply_to:
    - spectrum_max
    - spectrum_min
    result: spectra
  - kind: singleplot
    type: SinglePlotter2D
    properties:
      parameters:
        tight_layout: true
      properties:
        figure:
          dpi: 300
      type: contourf
    result: 2D
  - kind: compositeplot
    type: CompositePlotter
    properties:
      properties:
        figure:
          dpi: 150
          size: [8, 8]
      grid_dimensions: [2, 2]
      subplot_locations:
        - [0, 0, 1, 1]
        - [0, 1, 1, 1]
        - [1, 0, 1, 1]
      plotter:
        - 2D
        - transients
        - spectra
      filename: characteristics.png

Result

../_images/show-characteristics.png

Characteristics of a tr-EPR dataset at a glance. The 2D plot in the top left panel provides an overview of the entire dataset, while the transients and spectra obtained for the global maximum and minimum, respectively, are presented parallel to the corresponding axes of the 2D plot. In this particular case, the spectra for maximum and minimum entirely overlap, meaning that maximum and minimum of the signal occur at the same time after the laser flash.