Removed unnecessary origin keywords #26608

gautamsagar99 · 2023-08-26T19:42:15Z

PR summary

Removed origin keyword as it is not required in the provided examples.
https://matplotlib.org/devdocs/gallery/images_contours_and_fields/contourf_demo.html

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oscargus · 2023-08-27T09:38:30Z

~~It does not produce identical results. Compare the second plot where the "innermost" part of the top-right contour is no longer yellow.~~

~~With that said, I do not know if it should be there, etc, or if one should add an example to show the difference with using the origin keyword.~~

rcomer · 2023-08-27T10:03:59Z

@oscargus which versions are you comparing? There seems to have been a bug in recent Matplotlib versions (but not main or the release candidate) that caused that yellow not to appear. I already confused myself with that a couple of days ago: https://discourse.matplotlib.org/t/cmap-set-over-and-set-under-not-working-in-newer-python-environments/23999

I also wondered if it worth adding an example to show use of origin, and I see @gautamsagar99 asked the same on the issue (#26600). I know there is also a tension with “how much is too much to put in an example”.

oscargus · 2023-08-27T10:05:49Z

Ahh, sorry I mixed up the versions (checked on my phone)...

story645 · 2023-08-27T17:55:12Z

I also wondered if it worth adding an example to show use of origin

I think here it'd be useful to clarify what sounds like a point of confusion. I'd also make it a standalone "origin" section of an existing example?

gautamsagar99 · 2023-08-27T18:39:46Z

Hey,

To clarify I am using matplotlib - 3.7.1 version and I used colab for testing all the examples.

Here is the link for colab:

https://colab.research.google.com/drive/1XnsYLa8Tr0zuLe4hRDRu4KBJcJKlEnXX?usp=sharing

If you want me to add a new section with the below example I can add it.

import matplotlib.pyplot as plt
import numpy as np

x = np.arange(1, 10)
y = x.reshape(-1, 1)
h = x * y

cs = plt.contourf(h, levels=[10, 30, 50],
colors=['#808080', '#A0A0A0', '#C0C0C0'], extend='both', origin="upper")
cs.cmap.set_over('red')
cs.cmap.set_under('blue')
cs.changed()

story645 · 2023-08-27T18:59:12Z

building on your example, I think a side by side might be clearest:

x = np.arange(1, 10)
y = x.reshape(-1, 1)
h = x * y

fog, (ax1, ax2) = plt.subplots(ncols=2)
for (ax, origin) in [(ax1, 'upper'), (ax2, 'lower')]:
  ax.set_title(f"origin={origin}")
  cs = ax.contourf(h, levels=[10, 30, 50],
      colors=['#808080', '#A0A0A0', '#C0C0C0'], extend='both', origin=origin)
  cs.cmap.set_over('red')
  cs.cmap.set_under('blue')
  cs.changed()

and I'm a big fan here of using sphinx headings for each of the examples 'cause they all demonstrate a different feature?

gautamsagar99 · 2023-08-27T21:53:16Z

@rcomer Let me add a new section below which clearly populates the example using origin keyword.

@story645 Yes we can add side by side which will be clearly differentiating for lower and upper origin value.

Let me Just add it and push it.

Thanks

gautamsagar99 · 2023-08-27T22:01:23Z

Finally I want to add The below section to the documentation:

"**Customizing Contour Plots with the origin Keyword: **

This section demonstrates how to use the origin parameter in Matplotlib's contourf function to adjust the positioning of grid data. The origin parameter specifies whether data coordinates originate from the upper left ('upper') or lower left ('lower') corner of the grid.

import matplotlib.pyplot as plt
import numpy as np

x = np.arange(1, 10)
y = x.reshape(-1, 1)
h = x * y

fig, (ax1, ax2) = plt.subplots(ncols=2)

for (ax, origin) in [(ax1, 'upper'), (ax2, 'lower')]:
    ax.set_title(f"origin={origin}")
    cs = ax.contourf(h, levels=[10, 30, 50],
                     colors=['#808080', '#A0A0A0', '#C0C0C0'],
                     extend='both', origin=origin)
    cs.cmap.set_over('red')
    cs.cmap.set_under('blue')
    cs.changed()

plt.show()

This code creates two side-by-side contour plots with different origin settings ('upper' and 'lower'). The contourf function utilizes the origin parameter to control how grid data coordinates are interpreted for plotting. The resulting visualizations highlight the effect of changing the origin on the contour plot's appearance."

story645 · 2023-08-29T01:25:32Z

@gautamsagar99 seems good to me. Since you're modifying this example, can you also put in headings id'ing the topics of the other examples? I also understand if not because it's out of scope here.

gautamsagar99 · 2023-08-29T02:05:20Z

@story645 I will keep this as heading "Customizing Contour Plots with the origin Keyword:", under it I will provide the example.

gautamsagar99 · 2023-08-29T03:53:11Z

@story645 I'm Confused regarding the images. Do we need to upload the image for the output(for the above example) or It is going to auto generate?

story645 · 2023-08-29T03:54:33Z

Auto generate - see https://matplotlib.org/devdocs/devel/document.html#write-examples-and-tutorials

gautamsagar99 · 2023-08-29T20:56:32Z

@story645 Thank you for your assistance! I've made the necessary changes and have also generated the documentation. Please review the updates and let me know if any further adjustments are required.

story645 · 2023-08-30T00:23:27Z

galleries/examples/images_contours_and_fields/contourf_demo.py

    fig.colorbar(cs, ax=ax, shrink=0.9)
    ax.set_title("extend = %s" % extend)
    ax.locator_params(nbins=4)

 plt.show()

+# %%
+# Customizing Contour Plots with the origin Keyword
+# ------------------


doc build is failing because this needs to go the whole length of the title

I will Adjust this in small sentence like "Contour Plots using origin Keyword" and modify similarly based on the previous titles.

it's not about the length of the title, it's that --------- needs to be the width of the title it's under

story645 · 2023-08-30T00:24:01Z

galleries/examples/images_contours_and_fields/contourf_demo.py

-                  linewidths=(3,),
-                  origin=origin)
+                  linewidths=(3,)
+                  )


I know this is wrapped in the original but can probably be one line

I will try to wrap this in a single line or two

story645 · 2023-08-30T00:24:42Z

galleries/examples/images_contours_and_fields/contourf_demo.py

+# %%
+# Customizing Contour Plots with the origin Keyword
+# ------------------
+# This section demonstrates how to use the origin parameter in Contour


what information is this sentence adding in addition to the section title?

This one I will think of nice sentence which makes more valuable and more precise in explaining the below code snippet.

gautamsagar99 · 2023-08-30T03:14:04Z

@story645 I have done all the changes I hope everything looks good. Let me know if there is anything if you might want me to modify.

timhoffm · 2023-08-30T09:15:40Z

galleries/examples/images_contours_and_fields/contourf_demo.py

+fig, (ax1, ax2) = plt.subplots(ncols=2)
+# Note: lower and upper are the values provided
+# to origin argument in contourf.
+for (ax, origin) in [(ax1, 'upper'), (ax2, 'lower')]:
+    ax.set_title(f"origin={origin}")
+    cs = ax.contourf(h, levels=[10, 30, 50], colors=[
+                     '#808080', '#A0A0A0', '#C0C0C0'], extend='both', origin=origin)
+    cs.cmap.set_over('red')
+    cs.cmap.set_under('blue')
+    cs.changed()


You can simplify this to:

Suggested change

fig, (ax1, ax2) = plt.subplots(ncols=2)

# Note: lower and upper are the values provided

# to origin argument in contourf.

for (ax, origin) in [(ax1, 'upper'), (ax2, 'lower')]:

ax.set_title(f"origin={origin}")

cs = ax.contourf(h, levels=[10, 30, 50], colors=[

'#808080', '#A0A0A0', '#C0C0C0'], extend='both', origin=origin)

cs.cmap.set_over('red')

cs.cmap.set_under('blue')

cs.changed()

fig, (ax1, ax2) = plt.subplots(ncols=2)

ax1.set_title("origin='upper'")

ax2.set_title("origin='lower'")

ax1.contourf(h, levels=np.arange(5, 70, 5), extend='both', origin="upper")

ax2.contourf(h, levels=np.arange(5, 70, 5), extend='both', origin="lower")

This look more optimized. Thanks, Let me add it.

story645

title case is a style issue that needs to be amended, the other suggestion is more for clarity,

story645 · 2023-08-30T14:49:39Z

galleries/examples/images_contours_and_fields/contourf_demo.py

+# Customizing Contour Plots with the origin Keyword
+# -------------------------------------------------
+# This code showcases contour plot customization using the origin keyword,
+# demonstrating distinct upper and lower origin perspectives.


Suggested change

# Customizing Contour Plots with the origin Keyword

# -------------------------------------------------

# This code showcases contour plot customization using the origin keyword,

# demonstrating distinct upper and lower origin perspectives.

# Orient contour plots using the `origin` keyword

# -------------------------------------------------

# This code demonstrates orienting contour plot data using the *origin* keyword.

Our convention is Title case - first word in title upper case, everything else lower case.
Also origin isn't a customization , it's a tell Matplotlib my data needs to be read from the lower left or upper left corner

@story645 Thank you for sharing. I will update the changes and push it.

hi, changes aren't showing up

oh is it, Let me recommit and push the latest changes again.

story645

Thanks for all your work! Would you like me to squash merge or do you want to try rebasing?

QuLogic · 2023-08-31T00:15:44Z

galleries/examples/images_contours_and_fields/contourf_demo.py

+# Orient contour plots using the origin keyword
+# -----------------------------------------------


Should match:

Suggested change

# Orient contour plots using the origin keyword

# -----------------------------------------------

# Orient contour plots using the origin keyword

# ---------------------------------------------

gautamsagar99 · 2023-08-31T00:33:32Z

Huge thanks to @story645 and @timhoffm

I wanted to express my sincere appreciation for your tremendous support during my first open source contribution. Your guidance in understanding automatic documentations with proper formatting and your help in fixing my mistakes were incredibly valuable. Thanks for making this journey so enriching!

story645 · 2023-08-31T00:47:49Z

Thanks! You need to make the change @QuLogic suggested, and also much credit to @rcomer for opening the issue & her and @oscargus for clarifying.

gautamsagar99 · 2023-08-31T03:29:57Z

Sure, Let me make that small change and push it.

…608-on-v3.8.x Backport PR #26608 on branch v3.8.x (Removed unnecessary origin keywords)

story645 · 2023-08-31T18:31:27Z

congrats on your first merged pr 🎊 hope to see you back for more!

gautamsagar99 · 2023-09-01T03:05:53Z

Thank you so much for your guidance throughout the process! Contributing to this open-source project has been an amazing learning experience, and I'm really grateful for the opportunity. I completely understand that reviewing and merging PRs is no small task, and your support in guiding me through it means a lot. Looking forward to continuing this journey and contributing more in the future! 🙌😊

Removed unnecessary origin keywords

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gautamsagar99 added 3 commits August 28, 2023 23:14

Merge branch 'matplotlib:main' into gautamsagar99/contourf-origin#26600

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Added Contourf example using origin

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Build the documentation for Contourf_demo.py

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story645 requested changes Aug 30, 2023

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Modified Documentation for Contourf_demo.py

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Optimized the documentation for Contourf_demo.py

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story645 approved these changes Aug 30, 2023

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story645 added this to the v3.8-doc milestone Aug 30, 2023

story645 added the Documentation: examples files in galleries/examples label Aug 30, 2023

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gautamsagar99 added 2 commits August 30, 2023 15:06

Modified documentation for Contourf_demo.py

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Enhanced documentation for Contourf_demo.py

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story645 linked an issue Aug 31, 2023 that may be closed by this pull request

[Doc]: contourf demo use of origin keyword #26600

Closed

Final Enhancement in documentation for Contourf_demo.py

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timhoffm merged commit d3afa55 into matplotlib:main Aug 31, 2023
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meeseeksmachine mentioned this pull request Aug 31, 2023

Backport PR #26608 on branch v3.8.x (Removed unnecessary origin keywords) #26658

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meeseeksmachine pushed a commit to meeseeksmachine/matplotlib that referenced this pull request Aug 31, 2023

Backport PR matplotlib#26608: Removed unnecessary origin keywords

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QuLogic modified the milestones: v3.8-doc, v3.8.0 Aug 31, 2023

QuLogic added a commit that referenced this pull request Aug 31, 2023

Merge pull request #26658 from meeseeksmachine/auto-backport-of-pr-26…

f76bdcb

…608-on-v3.8.x Backport PR #26608 on branch v3.8.x (Removed unnecessary origin keywords)

ksunden mentioned this pull request Sep 15, 2023

merge up v3.8.0 #26785

Merged

5 tasks

		# Orient contour plots using the origin keyword
		# -----------------------------------------------

Removed unnecessary origin keywords #26608

Removed unnecessary origin keywords #26608

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gautamsagar99 commented Aug 26, 2023 • edited

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