imshow and colors

Community matplotlib-users
1

Hi: How many colors do images created via:

    > imshow(Zi, cmap=cm.jet)

    > (Zi = some data matrix) have?

    > Are these true color? 256? Is there a simple way to define
    > these things?

The following image parameters can be configured from your rc file

### images
image.aspect : free # free | preserve
image.interpolation : bilinear # see help(imshow) for options
image.cmap : jet # gray | jet
image.lut : 256 # the size of the colormap lookup table
image.origin : upper # lower | upper

The image.lut parameter controls the size of the lookup table. You
can change the default in the rc file, or dynamically in a single
python session using the rc function. Eg,

# default cmap is now 100 level grayscale by cm.jet and cm.gray unaffected
>>> rc('image', lut=100, cmap='gray')
>>> imshow(X) # show X with default cmap

But you can also create your own color maps at any time using the
cm.get_cmap function

  >>> jet512 = cm.get_cmap('jet', 512)
  >> imshow(X, cmap=jet512)

Should work.

JDH

2

.....
But you can also create your own color maps at any time using the
cm.get_cmap function

>>> jet512 = cm.get_cmap('jet', 512)
>> imshow(X, cmap=jet512)

Should work.

Yes, thanks.
Just one more question. Recently (in the last couple of versions I think), there has been a change and now the 'o' line markers (circles) are filled in by default.
For example:

    plot(xp,yp,'ok')

gives sold black circles.

I would like my circles to not be filled; just have the border so that the inside is transparent.
Is this something that is settable?

Thanks,

···

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Peter Groszkowski Gemini Observatory
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