Matplotlib & Basemap / What is the Best Graphical Back-end for Raster Data Display (.png) ?

Community matplotlib-users
1

Dear colleagues,

I like to receive an advice about the
best back-end choice for Matplotlib & Basemap to generate large .png
images in a background processing mode.
Having issues with the pre-compiled
“Agg” package which does not work under my machine architecture.
Also not able to recompile the Agg 2.5
package as its build throws an error
at the build script autogen.sh. Error:

./configure: line 15546: syntax error near
unexpected token $SDL_VERSION,' ./configure: line 15546:AM_PATH_SDL($SDL_VERSION,’

When bypassing this line it runs into
another dependency which is blocking the make install process.

libtool: link: cannot find the library…/src/platform/X11/libaggplatformX11.la’
or unhandled argument ../src/platform/X11/libaggplatformX11.la'
Makefile:1166: recipe for target 'aa_demo' failed
make[1]: *** [aa_demo] Error 1
make[1]: Leaving directory '/data/Downloads/agg/agg-2.5/examples'
Makefile:481: recipe for target 'install-recursive' failed
make: *** [install-recursive] Error 1

I do not plan to use any interactive
access, so my guess is that excluding X11 libraries should work OK.

My test showed that the “Cairo”
package is working fine, but its quality (vector oriented) is not as good
compared to the Agg raster display. Case the “Agg”
is not able to install on my machine,
is there an alternate graphical back-end available under SuSE environments?

Regards,
Claude Falbriard
Certified IT Specialist L2 - Middleware

···

**Phone:**55-13-99662-5703 | Mobile:55-13-98117-3316E-mail: claudef@…3779…

2

Matplotlib will not work at all without AGG. Even the AGG-less backends still use AGG for image handling (imshow() and such).

We can not guarantee that matplotlib would work with agg 2.5, as that is the GPL’ed version. We develop against a patched 2.4 branch of AGG (which is BSD-licensed), which is distributed with our source, and is built as part of our build process. Have you tried building matplotlib directly from our source without a system install of AGG?

Cheers

Ben Root

···

On Thu, Mar 3, 2016 at 6:34 AM, Claude Falbriard <claudef@…3779…> wrote:

Dear colleagues,

I like to receive an advice about the
best back-end choice for Matplotlib & Basemap to generate large .png
images in a background processing mode.
Having issues with the pre-compiled
“Agg” package which does not work under my machine architecture.
Also not able to recompile the Agg 2.5
package as its build throws an error
at the build script autogen.sh. Error:

./configure: line 15546: syntax error near
unexpected token $SDL_VERSION,' ./configure: line 15546: AM_PATH_SDL($SDL_VERSION,’

When bypassing this line it runs into
another dependency which is blocking the make install process.

libtool: link: cannot find the library …/src/platform/X11/libaggplatformX11.la’
or unhandled argument ../src/platform/X11/libaggplatformX11.la'
Makefile:1166: recipe for target 'aa_demo' failed
make[1]: *** [aa_demo] Error 1
make[1]: Leaving directory '/data/Downloads/agg/agg-2.5/examples'
Makefile:481: recipe for target 'install-recursive' failed
make: *** [install-recursive] Error 1

I do not plan to use any interactive
access, so my guess is that excluding X11 libraries should work OK.

My test showed that the “Cairo”
package is working fine, but its quality (vector oriented) is not as good
compared to the Agg raster display. Case the “Agg”
is not able to install on my machine,
is there an alternate graphical back-end available under SuSE environments?

Regards,
Claude Falbriard
Certified IT Specialist L2 - Middleware

**Phone:**55-13-99662-5703 | Mobile:55-13-98117-3316E-mail: claudef@…3779…

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3

Is it so? I never found such strong statement in the docs.

1. SVG backend produces vector graphics, no rasterisation in principle, so why AGG?
2. Cairo uses its own engine. Why AGG?
3. Image (PNG) "production" from curves, etc. uses AntiGrain, but if imshow() shows an image which is just a pixel array, there is no manipulation needing AGG, an element (triple RGB) becomes a pixel, and that's it.

Jerzy Karczmarczuk

···

Le 03/03/2016 15:43, Benjamin Root a écrit :

Matplotlib will not work at all without AGG. Even the AGG-less backends still use AGG for image handling (imshow() and such).

4

AGG is used for image handling, particularly for handling transforms, scaling, interpolation and such. The AxesImage object that you get from calling imshow() is handled through the AGG library. This is true regardless of the backend being used because it is based in the AxesImage class (and others). An SVG of a plot that used imshow() has raster data in it that comes from AGG (and you can choose to rasterize other things, as well). Cairo still needs the image buffer.

So, the distinction is the use of the AGG library, and the use of the AGG backend. The AGG library is required, but the AGG backend is not (but highly recommended).

I will admit that I didn’t have this distinction very clear in my own head until very recently when reviewing some PRs that reworked the image handling architecture. I hope that clears it up for you, too.

Cheers!

Ben Root

···

On Thu, Mar 3, 2016 at 10:05 AM, Jerzy Karczmarczuk <jerzy.karczmarczuk@…4713…> wrote:

Le 03/03/2016 15:43, Benjamin Root a écrit :

Matplotlib will not work at all without AGG. Even the AGG-less

backends still use AGG for image handling (imshow() and such).

Is it so? I never found such strong statement in the docs.

  1. SVG backend produces vector graphics, no rasterisation in principle,

so why AGG?

  1. Cairo uses its own engine. Why AGG?

  2. Image (PNG) “production” from curves, etc. uses AntiGrain, but if

imshow() shows an image which is just a pixel array, there is no

manipulation needing AGG, an element (triple RGB) becomes a pixel, and

that’s it.

Jerzy Karczmarczuk

Site24x7 APM Insight: Get Deep Visibility into Application Performance

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5

Dear colleagues,
Yes, I’ve downloaded the latest stable
image of Matplotlib source from the pypi repository matplotlib-1.5.1.tar.gz,
running the commands: sudo python setup.py buildand sudo python setup.py install.

When executing larger plots, the Agg
crashes with a segmentation fault message. My guess is that the c header
files are not compiled with the correct platform setting (s390x). Is
there a way to rebuild
the c prerequisites used by the embedded
Agg framework?

Thanks in advance for your advice.
Regards,
Claude Falbriard
Certified IT Specialist L2 - Middleware

···

Phone:55-13-99662-5703 |
Mobile: 55-13-98117-3316E-mail: claudef@…3779…

From:
Benjamin Root <ben.v.root@…287…>
To:
Claude Falbriard/Brazil/IBM@…4709…
Cc:
Matplotlib Users matplotlib-users@lists.sourceforge.net
Date:
03/03/2016 11:44
Subject:
Re: [Matplotlib-users]
Matplotlib & Basemap / What is the Best Graphical Back-end for Raster
Data Display (.png) ?

Matplotlib will not work at all without AGG. Even the
AGG-less backends still use AGG for image handling (imshow() and such).

We can not guarantee that matplotlib would work with agg
2.5, as that is the GPL’ed version. We develop against a patched 2.4 branch
of AGG (which is BSD-licensed), which is distributed with our source, and
is built as part of our build process. Have you tried building matplotlib
directly from our source without a system install of AGG?

Cheers
Ben Root

On Thu, Mar 3, 2016 at 6:34 AM, Claude Falbriard <claudef@…3779…> wrote:
Dear colleagues,

I like to receive an advice about the best back-end choice for Matplotlib
& Basemap to generate large .png images in a background processing
mode.
Having issues with the pre-compiled “Agg” package which does
not work under my machine architecture. Also not able to recompile the
Agg 2.5
package as its build throws an error at the build script autogen.sh. Error:

./configure: line 15546: syntax error near unexpected token $SDL_VERSION,' ./configure: line 15546:AM_PATH_SDL($SDL_VERSION,’

When bypassing this line it runs into another dependency which is blocking
the make install process.`

libtool: link: cannot find the library ../src/platform/X11/libaggplatformX11.la' or unhandled argument…/src/platform/X11/libaggplatformX11.la’
Makefile:1166: recipe for target ‘aa_demo’ failed
make[1]: *** [aa_demo] Error 1
make[1]: Leaving directory ‘/data/Downloads/agg/agg-2.5/examples’
Makefile:481: recipe for target ‘install-recursive’ failed
make: *** [install-recursive] Error 1`

I do not plan to use any interactive access, so my guess is that excluding
X11 libraries should work OK.

My test showed that the “Cairo” package is working fine,
but its quality (vector oriented) is not as good compared to the Agg raster
display. Case the “Agg”
is not able to install on my machine, is there an alternate graphical back-end
available under SuSE environments?
Regards,
Claude Falbriard
Certified IT Specialist L2 - Middleware

**Phone:**55-13-99662-5703| Mobile:55-13-98117-3316E-mail: claudef@…3779…

Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140

Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users