Initial draft of SpectrogramMeta classes

[Amityush-lgtm]

PR Description

Fixes #243

Implementing a metadata class hierarchy for radiospectra, following the pattern used in sunraster and the LC Radio Workshop metadata requirements.
I tried to make some flowcharts as well, will attach them too.

Changes:

• Added SpectrogramMetaABC and SpectrogramMeta (backed by NDMeta) in radiospectra/spectrogram/meta.py
• Added WAVESMeta and CALISTOMeta instrument specific subclasses for initial setup
• Updated GenericSpectrogram to wrap raw dict metadata into SpectrogramMeta automatically
• Added tests for the new meta class

AI Assistance Disclosure

AI tools were used for:

• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
• Documentation (including examples)
• Research and understanding
• No AI tools were used

Regardless of AI use, the human contributor remains fully responsible for correctness, design choices, licensing compatibility, and long-term maintainability.

This is an initial draft, so I've just tried to make the changes in WAVES and CALISTO, if it looks in the right direction then I'll add the remaining subclasses also. Let me know your thoughts on this @samaloney and @hayesla.

[Amityush-lgtm]

Sharing the flowchart i used while designing this:

[samaloney]

I think a short description and the type info should be encode here for each property e.g.

def instrument(self) -> str:
    """
    Name of the instrument
    """
    pass

and then here if we only return str then the default south be "" if that better or worse then returning a str or none e.g. -> str|None

[Amityush-lgtm]

for properties like date_start, frequency_rangeor data_units, what should i write for them??

[samaloney]

"Start of the observation" Time
"Frequency range of observation" Quantity
"Unit for the data" Unit

Maybe we don't need the docstrings for them all but they types would be good

[Amityush-lgtm]

One more doubt, what would you prefer for observer_location and data_mask?

[samaloney]

Also you can embed mermaid charts directly in GitHub doesn't match exactly the UML but close enough

classDiagram
    direction TB

    class NDMetaABC {
        <<ndcube.meta>>
    }

    class SpectrogramMetaABC {
        <<abstract>>
        +instrument
        +observatory
        +detector
        +date_start
        +date_end
        ...
    }

    class NDMeta {
        <<ndcube.meta>>
        dict subclass
        +axes
        ...
        +slice()
        +add()
        +rebin()
    }

    class SpectrogramMeta {
        <<concrete base>>
        dict-backed via NDMeta
        +instrument
        +observatory
        +detector
        +date_start
        +date_end
        ...
    }

    class WAVESMeta {
        +background
        +receiver
    }

    class CALISTOMeta {
        +observer_location
    }

    class OtherInstrumentMetas {
        <<...>>
    }

    %% Relationships
    SpectrogramMetaABC --|> NDMetaABC : inherits
    NDMeta --|> NDMetaABC : inherits

    SpectrogramMeta --|> NDMeta : inherits
    SpectrogramMeta ..|> SpectrogramMetaABC : implements

    WAVESMeta --|> SpectrogramMeta
    CALISTOMeta --|> SpectrogramMeta
    OtherInstrumentMetas --|> SpectrogramMeta

Loading

[samaloney]

I think this is aleady cover by the unit in NDCube

[samaloney]

Maybe observe_coordinate would be better and this should be a SkyCoord | None

[Amityush-lgtm]

Got it, I'm working on it

[Amityush-lgtm]

Also you can embed mermaid charts directly in GitHub doesn't match exactly the UML but close enough

classDiagram
    direction TB

    class NDMetaABC {
        <<ndcube.meta>>
    }

    class SpectrogramMetaABC {
        <<abstract>>
        +instrument
        +observatory
        +detector
        +date_start
        +date_end
        ...
    }

    class NDMeta {
        <<ndcube.meta>>
        dict subclass
        +axes
        ...
        +slice()
        +add()
        +rebin()
    }

    class SpectrogramMeta {
        <<concrete base>>
        dict-backed via NDMeta
        +instrument
        +observatory
        +detector
        +date_start
        +date_end
        ...
    }

    class WAVESMeta {
        +background
        +receiver
    }

    class CALISTOMeta {
        +observer_location
    }

    class OtherInstrumentMetas {
        <<...>>
    }

    %% Relationships
    SpectrogramMetaABC --|> NDMetaABC : inherits
    NDMeta --|> NDMetaABC : inherits

    SpectrogramMeta --|> NDMeta : inherits
    SpectrogramMeta ..|> SpectrogramMetaABC : implements

    WAVESMeta --|> SpectrogramMeta
    CALISTOMeta --|> SpectrogramMeta
    OtherInstrumentMetas --|> SpectrogramMeta

Loading

Thats so cool, I didn't know GitHub supported Mermaid diagrams. I'll definitely try using them, Thanks a lot!

[Amityush-lgtm]

Should i add the rest of the classes in this PR or like break it in different PRs??

[samaloney]

I think adding the classes necessary to handle the instruments that are currently supported would make sense.

[Amityush-lgtm]

I have added the remaining classes, let know your thoughts on this @samaloney