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J
JBlackhole16-Pearl
16-Pearl
April 15, 2016
Question

Colour map for Contour plot ?

  • April 15, 2016
  • 1 reply
  • 1899 views

To all,

I have created a contour plot and trying to control the scale and/or the colour scheme.

Under the advanced properties I can see the option 'choose colormap'

Q1: with the (default) rainbow map, is red the high value or low value (on the z axis)? look high it's the high value

Q2: I believe (from the doc) one can allocate a colour map ( SaveColormap and LoadColormap functions)

Can this be used to create one own scale so that

[0-0.1] = a colour

]0.1-0.2] = another colour

...

]0.9-1] = red

a 10 band colour map

Thanks

Regards

1 reply

S
StuartBruff23-Emerald V
23-Emerald V
April 15, 2016

J B wrote:

To all,

I have created a contour plot and trying to control the scale and/or the colour scheme.

Under the advanced properties I can see the option 'choose colormap'

Q1: with the (default) rainbow map, is red the high value or low value (on the z axis)? look high it's the high value

Q2: I believe (from the doc) one can allocate a colour map ( SaveColormap and LoadColormap functions)

Can this be used to create one own scale so that

[0-0.1] = a colour

]0.1-0.2] = another colour

...

]0.9-1] = red

a 10 band colour map

Thanks

Regards

Does the attached help any?

You'll need to add the correct path for you Mathcad colormap folder.

Stuart

    J
    JBlackhole16-PearlAuthor
    16-Pearl
    April 15, 2016

    thanks a lot Stuart. Will take me a while to go through the provided example/data

    I suspect somewhere there is an example on how to set up a "fixed" 10 value colour band

    S
    StuartBruff23-Emerald V
    23-Emerald V
    April 15, 2016

    J B wrote:

    thanks a lot Stuart. Will take me a while to go through the provided example/data

    I suspect somewhere there is an example on how to set up a "fixed" 10 value colour band

    I don't think it does that ... the colour mapping interpolates, IIRC, so if there is no block banding of the colours (they smear together).  However, here's a simple function that should help.

    Just create a string of the RGB values of your chosen colours (I used a standard colour picker and chose some at random), convert it to a matrix (using my conversion routine str2mat), pass to the block colour mapping function below and then save as a colormap.  (You could also just type the coefficients straight into a 10x3 matrix rather than do the conversion, but I find the string method easier)

    The new colour map is the 3rd from the right in the map below.

    Staurt

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