# Approximate sketch of "units flow" in ScopeSim

Effects that change units are shown in hexagonal boxes.
Rectangular boxes are basically `ImageHDU` wrappers.
Parallelogram boxes are lists of other entities.

```{mermaid}
%%{init: {"theme": "dark"} }%%
flowchart TB
    Source(["`Source
              [ph/cm2/s/AA(/arcsec2)]
              [PHOTLAM(/arcsec2)]`"])
    FOV1[/"`FOV.fields
            [ph/cm2/s/AA(/arcsec2)]`"/]
    FOV2["`FOV.hdu
           [ph/s]`"]
    FOV3[/"`FOV.fields
            [ph/cm2/s/AA(/arcsec2)]`"/]
    FOV4["`FOV.hdu
           [ph/s/um/arcsec2]`"]
    FOV5["`FOV.hdu
           [ph/s]`"]
    SPT{{"`SpectralTrace:
           dispersion, sum(sky)`"}}
    IMP["`ImagePlane
          [ph/s]`"]
    Det1["`Detector
           [ph/s]`"]
    QECurve{{"`QECurve:
               ph/s -> e-/s`"}}
    Det2["`Detector
           [e-/s]`"]
    SE{{"`ExposureIntegration:
          sum(time)`"}}
    Det3["`Detector
           [e-]`"]
    ADC{{"`ADConversion:
           e- -> ADU`"}}
    Det4["`Detector
           [ADU]`"]
    Output(["`Output
              [ADU]`"])

    Source-- extract -->FOV1
    subgraph Imaging
        FOV1-- "sum(wave), *area" -->FOV2
    end
    Source-- extract -->FOV3
    subgraph Spectroscopy
        FOV3-- *area -->FOV4
        FOV4-->SPT
        SPT-->FOV5
    end
    FOV2-- project -->IMP
    FOV5-- project -->IMP
    IMP-- "extract" -->Det1
    Det1-->QECurve
    QECurve-->Det2
    Det2-->SE
    SE-->Det3
    Det3-->ADC
    ADC-->Det4
    Det4-->Output
```