[Matplotlib-users] Interpolation method of python matplotlib contourf

Hello to all

I want to ask what is the default interpolation method of python matplotlib contourf? Where can I find relative documentation? Could someone help me?

Best regards

Sakis

···
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar@live.com

Hello Sakis,

All of Matplotlib’s contouring functions (contour, contourf, tricontour, tricontourf) use linear interpolation along grid edges. This is not explicitly documented anywhere.

Are there other interpolation options that you would like? I can think of logarithmic as one possibility.

Ian

···

On Tue, 2 Feb 2021 at 10:08, Athanasios Karagiannidis <thankar@live.com> wrote:

Hello to all

I want to ask what is the default interpolation method of python matplotlib contourf? Where can I find relative documentation? Could someone help me?

Best regards

Sakis

Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: [thankar@live.com](mailto:thankar@live.com)

Matplotlib-users mailing list
Matplotlib-users@python.org
https://mail.python.org/mailman/listinfo/matplotlib-users

Hello Ian

Another interpolation may come handy in the future. Is it possible to control the interpolation method?

The fact that the current interpolation method is not documented is a pity. I need to reference it in a manuscript…

Sakis

···
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar@live.com

From: Ian Thomas ianthomas23@gmail.com
Sent: Tuesday, February 2, 2021 1:17 PM
To: Athanasios Karagiannidis thankar@live.com
Cc: matplotlib-users@python.org matplotlib-users@python.org
Subject: Re: [Matplotlib-users] Interpolation method of python matplotlib contourf

Hello Sakis,

All of Matplotlib’s contouring functions (contour, contourf, tricontour, tricontourf) use linear interpolation along grid edges. This is not explicitly documented anywhere.

Are there other interpolation options that you would like? I can think of logarithmic as one possibility.

Ian

On Tue, 2 Feb 2021 at 10:08, Athanasios Karagiannidis <thankar@live.com> wrote:

Hello to all

I want to ask what is the default interpolation method of python matplotlib contourf? Where can I find relative documentation? Could someone help me?

Best regards

Sakis

Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: [thankar@live.com](mailto:thankar@live.com)

Matplotlib-users mailing list
Matplotlib-users@python.org
https://mail.python.org/mailman/listinfo/matplotlib-users

Hi Sakis,

No, you cannot control the interpolation method, you are stuck with linear for now. It is on my wishlist for future improvements, but this is no help to you now.

To demonstrate that it is linear interpolation I would reference the code, e.g. https://github.com/matplotlib/matplotlib/blob/ea6803254567eaaa9adb027b541a6885d9fa246f/src/_contour.cpp#L1345-L1354 is the C++ interpolation function which is self-evidently linear interpolation. I am not sure if that link is good enough for a manuscript though.

Ian

···

On Tue, 2 Feb 2021 at 12:22, Athanasios Karagiannidis <thankar@live.com> wrote:

Hello Ian

Another interpolation may come handy in the future. Is it possible to control the interpolation method?

The fact that the current interpolation method is not documented is a pity. I need to reference it in a manuscript…

Sakis

Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: [thankar@live.com](mailto:thankar@live.com)

From: Ian Thomas <ianthomas23@gmail.com>
Sent: Tuesday, February 2, 2021 1:17 PM
To: Athanasios Karagiannidis <thankar@live.com>
Cc: matplotlib-users@python.org <matplotlib-users@python.org>
Subject: Re: [Matplotlib-users] Interpolation method of python matplotlib contourf

Hello Sakis,

All of Matplotlib’s contouring functions (contour, contourf, tricontour, tricontourf) use linear interpolation along grid edges. This is not explicitly documented anywhere.

Are there other interpolation options that you would like? I can think of logarithmic as one possibility.

Ian

On Tue, 2 Feb 2021 at 10:08, Athanasios Karagiannidis <thankar@live.com> wrote:

Hello to all

I want to ask what is the default interpolation method of python matplotlib contourf? Where can I find relative documentation? Could someone help me?

Best regards

Sakis

Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: [thankar@live.com](mailto:thankar@live.com)

Matplotlib-users mailing list
Matplotlib-users@python.org
https://mail.python.org/mailman/listinfo/matplotlib-users

Hello again Ian

I can work with linear, no problem!

Regarding, the reference: The link may not be sufficient. I depend. I guess I may have to find a general reference for the linear interpolation to incorporate in my manuscript.

Thank you very much!

Best regards

Sakis

···
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar@live.com

From: Ian Thomas ianthomas23@gmail.com
Sent: Tuesday, February 2, 2021 2:44 PM
To: Athanasios Karagiannidis thankar@live.com
Cc: matplotlib-users@python.org matplotlib-users@python.org
Subject: Re: [Matplotlib-users] Interpolation method of python matplotlib contourf

Hi Sakis,

No, you cannot control the interpolation method, you are stuck with linear for now. It is on my wishlist for future improvements, but this is no help to you now.

To demonstrate that it is linear interpolation I would reference the code, e.g. https://github.com/matplotlib/matplotlib/blob/ea6803254567eaaa9adb027b541a6885d9fa246f/src/_contour.cpp#L1345-L1354 is the C++ interpolation function which is self-evidently linear interpolation. I am not sure if that link is good enough for a manuscript though.

Ian

On Tue, 2 Feb 2021 at 12:22, Athanasios Karagiannidis <thankar@live.com> wrote:

Hello Ian

Another interpolation may come handy in the future. Is it possible to control the interpolation method?

The fact that the current interpolation method is not documented is a pity. I need to reference it in a manuscript…

Sakis

Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: [thankar@live.com](mailto:thankar@live.com)

From: Ian Thomas <ianthomas23@gmail.com>
Sent: Tuesday, February 2, 2021 1:17 PM
To: Athanasios Karagiannidis <thankar@live.com>
Cc: matplotlib-users@python.org <matplotlib-users@python.org>
Subject: Re: [Matplotlib-users] Interpolation method of python matplotlib contourf

Hello Sakis,

All of Matplotlib’s contouring functions (contour, contourf, tricontour, tricontourf) use linear interpolation along grid edges. This is not explicitly documented anywhere.

Are there other interpolation options that you would like? I can think of logarithmic as one possibility.

Ian

On Tue, 2 Feb 2021 at 10:08, Athanasios Karagiannidis <thankar@live.com> wrote:

Hello to all

I want to ask what is the default interpolation method of python matplotlib contourf? Where can I find relative documentation? Could someone help me?

Best regards

Sakis

Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: [thankar@live.com](mailto:thankar@live.com)

Matplotlib-users mailing list
Matplotlib-users@python.org
https://mail.python.org/mailman/listinfo/matplotlib-users


Hi all,

Sakis, are you saying that if the (linear) interpolation scheme was simply mentionned in the relevant docstring (I imagine some place like `matplotlib.axes.contour{f}` or `matplotlib.contour.{Quad}ContourSet`), then it would be enough regarding your need for a reference? I guess that a quick PR to fix what seems to be a small yet quite unfortunate
hole in the documentation anyway would be welcome, would it not?

Best regards,
Adrien

···

Le 02/02/2021 à 14:49, Athanasios Karagiannidis a écrit :

Hello again Ian

I can work with linear, no problem!

Regarding, the reference: The link may not be sufficient. I depend. I guess I may have to find a general reference for the linear interpolation to incorporate in my manuscript.

Thank you very much!

Best regards

Sakis

Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar@live.com

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
*From:* Ian Thomas <ianthomas23@gmail.com>
*Sent:* Tuesday, February 2, 2021 2:44 PM
*To:* Athanasios Karagiannidis <thankar@live.com>
*Cc:* matplotlib-users@python.org <matplotlib-users@python.org>
*Subject:* Re: [Matplotlib-users] Interpolation method of python matplotlib contourf

Hi Sakis,

No, you cannot control the interpolation method, you are stuck with linear for now. It is on my wishlist for future improvements, but this is no help to you now.

To demonstrate that it is linear interpolation I would reference the code, e.g. matplotlib/_contour.cpp at ea6803254567eaaa9adb027b541a6885d9fa246f · matplotlib/matplotlib · GitHub is the C++ interpolation function which is self-evidently linear interpolation. I am not sure if that link is good enough for a manuscript though.

Ian

On Tue, 2 Feb 2021 at 12:22, Athanasios Karagiannidis <thankar@live.com <mailto:thankar@live.com>> wrote:

    Hello Ian

    Another interpolation may come handy in the future. Is it possible to control the interpolation method?

    The fact that the current interpolation method is not documented is a pity. I need to reference it in a manuscript...

    Sakis

    Athanasios F. Karagiannidis
    Physicist, PhD Meteorology and Climatology
    E-mail: thankar@live.com <mailto:thankar@live.com>

    ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    *From:* Ian Thomas <ianthomas23@gmail.com <mailto:ianthomas23@gmail.com>>
    *Sent:* Tuesday, February 2, 2021 1:17 PM
    *To:* Athanasios Karagiannidis <thankar@live.com <mailto:thankar@live.com>>
    *Cc:* matplotlib-users@python.org <mailto:matplotlib-users@python.org> <matplotlib-users@python.org <mailto:matplotlib-users@python.org>>
    *Subject:* Re: [Matplotlib-users] Interpolation method of python matplotlib contourf
    
    Hello Sakis,

    All of Matplotlib's contouring functions (contour, contourf, tricontour, tricontourf) use linear interpolation along grid edges. This is not explicitly documented anywhere.

    Are there other interpolation options that you would like? I can think of logarithmic as one possibility.

    Ian

    On Tue, 2 Feb 2021 at 10:08, Athanasios Karagiannidis <thankar@live.com <mailto:thankar@live.com>> wrote:

        Hello to all

        I want to ask what is the default interpolation method of python matplotlib contourf? Where can I find relative documentation? Could someone help me?

        Best regards

        Sakis

        Athanasios F. Karagiannidis
        Physicist, PhD Meteorology and Climatology
        E-mail: thankar@live.com <mailto:thankar@live.com>

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