2.3.6. vacumm.misc.color – Colors and colormaps

2.3.6.1. Overview

Attributes:

bistre decimaitre jean_pierre land

ocean sea simple_colors

Functions:

RGB() RGBA() anamorph_cmap() auto_cmap_topo() change_luminosity() change_saturation() change_value() cmap_ajete() cmap_ajets() cmap_bathy() cmap_br() cmap_br2() cmap_bwr() cmap_bwre() cmap_chla() cmap_currents() cmap_custom() cmap_dynamic_cmyk_hymex() cmap_eke() cmap_gmt() cmap_grey() cmap_jet() cmap_jete() cmap_jets() cmap_land() cmap_linear() cmap_magic() cmap_mg() cmap_ncview_rainbow() cmap_nice_gfdl() cmap_pe() cmap_previmer() cmap_previmer2() cmap_rainbow() cmap_rainbow_sst_hymex() cmap_rb()

cmap_red_tau_hymex() cmap_regular_steps() cmap_rnb2_hymex() cmap_rs() cmap_rs() cmap_smoothed_regular_steps() cmap_smoothed_steps() cmap_srs() cmap_ss() cmap_ssec() cmap_steps() cmap_topo() cmap_white_centered_hymex() cmap_wjet() cmap_wjets() cmap_wr() cmap_wre() cmaps_gmt() cmaps_mpl() cmaps_registered() cmaps_vacumm() darken() desaturate() discretise_cmap() get_cmap() pastelise() plot_cmap() plot_cmaps() print_cmaps_gmt() rainbow() saturate() show_cmap() to_grey() to_shadow() whiten()

Classes:

RangedLinearSegmentedColormap Scalar2RGB StepsNorm inverse()

2.3.6.2. Content

Inheritance diagram:  

Variables and utilities about colors and color maps

List of all available colormaps in matplotlib, including VACUMM colormaps (plotted with plot_cmaps())

RGB(arg)

Returns an RGB tuple of three floats from 0-1.

arg can be an RGB or RGBA sequence or a string in any of several forms:

1. a letter from the set ‘rgbcmykw’
2. a hex color string, like ‘#00FFFF’
3. a standard name, like ‘aqua’
4. a string representation of a float, like ‘0.4’, indicating gray on a 0-1 scale

if arg is RGBA, the A will simply be discarded.

RGBA(arg, alpha=None)

Returns an RGBA tuple of four floats from 0-1.

For acceptable values of arg, see to_rgb(). In addition, if arg is “none” (case-insensitive), then (0,0,0,0) will be returned. If arg is an RGBA sequence and alpha is not None, alpha will replace the original A.

class RangedLinearSegmentedColormap(name, segmentdata, N=256, start=0.0, stop=1.0)

Bases: matplotlib.colors.Colormap

See also:matplotlib.colors.LinearSegmentedColormap

is_gray()

reversed(name=None)

Make a reversed instance of the Colormap.

Note

Function not implemented for base class.

name : str, optional

The name for the reversed colormap. If it’s None the name will be the name of the parent colormap + “_r”.

See LinearSegmentedColormap.reversed() and ListedColormap.reversed()

set_bad(color=u'k', alpha=None)

Set color to be used for masked values.

set_over(color=u'k', alpha=None)

Set color to be used for high out-of-range values. Requires norm.clip = False

set_under(color=u'k', alpha=None)

Set color to be used for low out-of-range values. Requires norm.clip = False

class Scalar2RGB(vminmax, cmap=None)

Bases: object

Converter from scalar to colors

Params:

• vminmax: Either an array or a tuple of (min,max).
• cmap, optional: A colormap.

Example:

>>> cmap = cmap_srs(['b', 'r'])
>>> c = Scalar2RGB((1.5, 20.6), cmap)
>>> print c(1.5, alpha=.5), c(10), c(20.6), c(50)
(0.0,0.0,1.0,0.5) (0.38,0.0,0.61) (1.0,0.0,0.0) (1.0,0.0,0.0)
>>> print c([1.5,10])
[[ 0.          0.          1.        ]
[ 0.38627451  0.          0.61372549]]

class StepsNorm(levels, log=False, masked=True, **kwargs)

Bases: matplotlib.colors.Normalize

Normalize a given value to the 0-1 range on a stepped linear or log scale

See tutorial Utilisation d’une palette à paliers irréguliers

autoscale(A)

Set vmin, vmax to min, max of A.

autoscale_None(A)

autoscale only None-valued vmin or vmax.

inverse(pos)

static process_value(value)

Homogenize the input value for easy and efficient normalization.

value can be a scalar or sequence.

Returns result, is_scalar, where result is a masked array matching value. Float dtypes are preserved; integer types with two bytes or smaller are converted to N.float32, and larger types are converted to N.float. Preserving float32 when possible, and using in-place operations, can greatly improve speed for large arrays.

Experimental; we may want to add an option to force the use of float32.

scaled()

return true if vmin and vmax set

anamorph_cmap(cmap, transform, name=None)

Tranform a colormap with anamorphim

Params:

• cmap: Colormap.
• transform: Sorted array of float between 0 and 1.
• name: name of the colormap

auto_cmap_topo(varminmax=(0.0, 1.0), gzoom=1.0, xzoom=1.0, **kwargs)

Adjusted cmap_topo() colormap so that altitude 0 fall on center of full colormap by defaut

Params:

• varminmax: Define the min and max of topo ; it can be either :

  • a topo variable (array) from which min and max are computed
  • a tuple of (min, max) fo topo

• gzoom, optional: Global zoom in the colormap (>1.)

• xzoom, optional: Zoom out

  • the land colormap if more ocean,
  • the ocean colormap if more land.

bistre = (0.9609375, 0.87109375, 0.703125)

Land color

change_luminosity(c, f)

Change the luminosity

Params:

• c: color
• f: Factor between 0 and 1 with null impact at 0.5

change_saturation(c, f)

Change the saturation in HSV mode

Params:

• c: Color
• f: Factor between 0 and 1. Null effect at 0.5.

change_value(c, f)

Change de value in HSV mode

Params:

• c: Color
• f: Factor between 0 and 1. Null effect at 0.5.

cmap_ajete(w=0.02, name='vacumm_ajete', **kwargs)

Jet colormap with white at center and extremes, for anomaly plots

Sample:

cmap_ajets(wcol='w', name='vacumm_ajets', **kwargs)

Jet colormap with smoothed steps and white at center (for anomalies)

Params:

• wcol, optional: color of “white”
• other options are passed to cmap_smoothed_regular_steps()

Sample:

cmap_bathy(start=0.0, stop=1.0, name='vacumm_bathy', **kwargs)

Colormap for bathymetry maps

Sample:

cmap_br(sep=0.5, name='vacumm_br', **kwargs)

Blue->red colormap

Params:

• sep, optional: relative position of the blue/red transition in the map [default: 0.5]

Sample:

cmap_br2(sep=0.5, white=0.7, name='vacumm_br2', **kwargs)

Blue->light blue|light red-> red

Params:

• sep, optional: relative position of the blue/red transition in the map [default: 0.5]
• white, optional: Strenght of the whitening (see whiten()).

Sample:

cmap_bwr(wpos=0.5, wcol='w', name='vacumm_bwr')

Blue->white->red colormap

Params:

• white: relative position of white color in the map [default: 0.5]

Sample:

cmap_bwre(wpos=0.5, gap=0.1, wcol='w', name='vacumm_bwre', **kwargs)

Returns a violet->blue->white->red colormap->yellow

• white, optional: relative position of white color in the map [default: 0.5]
• gap, optional: Relative width of the pure central white gap [default: 0.1]

Sample:

cmap_chla(name='vacumm_chla', smoothed=True, **kwargs)

Colormap for Chlorophyll A

Sample: Source:

IDL code from F. Gohin.

cmap_currents(name='vacumm_currents', **kwargs)

A colormap for displaying currents

cmap_custom(colors, name='mycmap', ncol=256, ranged=False, register=True, **kwargs)

Quick colormap creation

Params:

• colors: Like [(color1, position1),(color2, position2), etc…] or dict(red=((pos1,r1a,r1b), (pos2,r2a,r2b)),etc…)
• ncol/N: Discretization.
• register: Register the colormap into matplotlib to be accessible with its name?

cmap_dynamic_cmyk_hymex(name='vacumm_dynamic_cmyk_hymex', **kwargs)

DYNAMIC_CMYK Colormap for HYMEX

Note

This colormap is registered in matplotlib under the name “vacumm_dynamic_cmyk_hymex”.

Sample:

cmap_eke(name='vacumm_eke', **kwargs)

Colormap for Eddy Kinetic Energy (from Barnier et al., 2006)

Added by G. Charria

cmap_gmt(name, register=True, **kwargs)

Get a colormap from GMT

Params:

• name: GMT colormap name OR .cpt file name.

See also:

cmaps_gmt() print_cmaps_gmt() get_cmap()

cmap_grey(start=0, end=1.0, name='vacumm_grey', **kwargs)

Grey colormap from position start to position end

Sample:

cmap_jet(smoothed=False, name='vacumm_jet', **kwargs)

Jet colormap

cmap_jete(name='vacumm_jete', **kwargs)

Jet colormap with extremes

Sample:

cmap_jets(name='vacumm_jets', **kwargs)

Jet colormap with smoothed steps

Params:

Passed to cmap_smoothed_regular_steps()

Samples:

• 
• 
• 

See also:

cmap_smoothed_regular_steps()

cmap_land(start=0.0, stop=1.0, name='vacumm_land', **kwargs)

Colormap for land maps

Params:

• start/stop, optional: Positions for a zoom in colormap.

Sample:

cmap_linear(c, **kwargs)

Basic linear map between colors

cmap_magic(n=None, stretch=0.4, mode='normal', white='.95', name='vacumm_magic', **kwargs)

Magic rainbow colormap

Based upon cmap_rainbow() with specificities:

• n may be for example an array of levels.
• smoothed is set to False by default.
• stretch is set negative by default (-attenuation).

Params:

• n, optional: Number of colors used or object with a length (like an array of levels).
• Extra keywords are passed to rainbow()

Example:

>>> ssta = MV2.arange(-2.6, 3.1, .1)
>>> cmap = cmap_magic(ssta, anomaly=True)
>>> cmap = cmap_magic(len(ssta))

Samples:

• 
• 
• 
• 
• 

cmap_mg(*args, **kwargs)

Shortcut to cmap_magic()

cmap_ncview_rainbow(name='vacumm_ncview_rainbow', **kwargs)

Colormap Rainbow from Ncview (http://fossies.org/dox/ncview-2.1.2/colormaps__rainbow_8h_source.html)

Source:http://fossies.org/dox/ncview-2.1.2/colormaps__rainbow_8h_source.html (ncview-2.1.2, G. Charria)

cmap_nice_gfdl(name='vacumm_nice_gfdl', **kwargs)

GFDL colormap (http://www.gfdl.noaa.gov/visualization)

Source:http://www.ncl.ucar.edu/Document/Graphics/ColorTables/nice_gfdl.shtml (included by G. Charria)

cmap_pe(red=0.8, name='vacumm_pe', **kwargs)

Colomap for positive extremes (white->grey->red)

Sample:

cmap_previmer(name='vacumm_previmer', **kwargs)

Colormap from PREVIMER Website (http://www.previmer.org)

Sample: Source:

http://www.previmer.org (F. Lecornu, G. Charria)

cmap_previmer2(name='vacumm_previmer2', **kwargs)

Colormap from PREVIMER Website (http://www.previmer.org)

Same as cmap_previmer() but extremes are used for set_under() and :meth`set_over`.

Sample: Source:

http://www.previmer.org (F. Lecornu, G. Charria)

cmap_rainbow(n=None, name='vacumm_rainbow', smoothed=True, mode='auto', **kwargs)

Rainbow colormap

Params:

• n, optional: Number of colors used (keyword passed to rainbow()).
• stretcher, first, last, middle, optional: See rainbow().
• rainbow_<param>, optional: <param> is passed to func:rainbow
• Extra keywords are passed to cmap_rs() or cmap_srs()

Example:

>>> cmap = cmap_magic(10, first='.5', mode='last')
>>> cmap = cmap_magic([5.,6.,7,8,9], stretcher='reduced_green')

Sample:

cmap_rainbow_sst_hymex(name='vacumm_rainbow_sst_hymex', **kwargs)

RAINBOW_SST Colormap for HYMEX

Note

This colormap is registered in matplotlib under the name “vacumm_rainbow_sst_hymex”.

Sample:

cmap_rb(*args, **kwargs)

Shortcut to cmap_rainbow()

cmap_red_tau_hymex(name='vacumm_red_tau_hymex', **kwargs)

RNB2 Colormap for HYMEX

Note

This colormap is registered in matplotlib under the name “vacumm_red_tau_hymex”.

Sample:

cmap_regular_steps(colors, steptype='stair', **kwargs)

Colormap by regular steps

Params:

• cols: [col1,col2,…]
• stretch, optional: Color darkening (<0) or whitening within steps [default: -.6]
• steptype, optional: ‘center’, ‘stair’ or ‘bounds’ [default: ‘center’]
• Other keywords are passed to cmap_steps()

See also:

cmap_steps() cmap_smoothed_steps() cmap_smoothed_regular_steps()

cmap_rnb2_hymex(name='vacumm_rnb2_hymex', **kwargs)

RNB2 Colormap for HYMEX

Note

This colormap is registered in matplotlib under the name “vacumm_rnb2_hymex”.

Sample:

cmap_rs(*args, **kwargs)

Shortcut to cmap_regular_steps()

cmap_rs(*args, **kwargs)

Shortcut to cmap_regular_steps()

cmap_smoothed_regular_steps(colors, steptype='center', **kwargs)

Smoothed regular steps

Params:

• colors: [(r1,g1,b1),…]
• Other keywords are passed to cmap_smoothed_steps()

See also:

cmap_steps() cmap_smoothed_steps() cmap_regular_steps() (cmap_regular_jets() for an example)

cmap_smoothed_steps(colors, stretch=None, rstretch=0, lstretch=0, name='vacumm_css', asdict=False, **kwargs)

Smoothed steps

Params:

• colors, optional: Central positions for each colors [(col1,pos1),…]

See also:cmap_steps() cmap_regular_steps() cmap_smoothed_regular_steps()

cmap_srs(*args, **kwargs)

Shortcut to cmap_smoothed_regular_steps()

cmap_ss(*args, **kwargs)

Shortcut to cmap_smoothed_steps()

cmap_ssec(name='vacumm_ssec', **kwargs)

Colormap from Ncview (http://fossies.org/dox/ncview-2.1.2/colormaps__ssec_8h_source.html)

Source:http://fossies.org/dox/ncview-2.1.2/colormaps__ssec_8h_source.html (ncview-2.1.2, G. Charria)

cmap_steps(cols, stretch=None, lstretch=0.0, rstretch=0.0, keepc=None, name='cmap_steps', **kwargs)

Colormap by steps

Params:

• cols: [(col1,pos1),(col2,pos2),…]
• lstretch, optional: Color darkening (<0) or whitening at start of steps (left)
• rstretch, optional: Same but at end of steps (right)
• keepc, optional: If lstretch and rstretch are both different from zero, it keeps center of steps intact, else it becomes a mean of left and right.
• ncol/N: Discretization.

.See also:

cmap_regular_steps() cmap_smoothed_steps() cmap_smoothed_regular_steps()

cmap_topo(start=0.0, stop=1.0, name='vacumm_topo', zero=0.5, over='k', under='#eeeeff', bad='0.5', **kwargs)

Colormap for bathy+land maps

Params:

• start/stop, optional: Positions for a zoom in colormap.
• zero, optional: Position of 0-depth color.
• over, optional: Color for values over maximal range (see set_over()).
• under, optional: Color for values under maximal range (see set_under()).
• bad, optional: Color for bad values (see set_bad()).

Sample: See also:

cmap_bathy() cmap_land()

cmap_white_centered_hymex(name='vacumm_white_centered_hymex', **kwargs)

RNB2 Colormap for HYMEX

Note

This colormap is registered in matplotlib under the name “vacumm_white_centered_hymex”.

Sample:

cmap_wjet(wcol='.95', smoothed=True, name='vacumm_wjet', **kwargs)

jet colormap with white (or another color) at beginning

Sample:

cmap_wjets(wcol='.95', name='vacumm_wjets', **kwargs)

White jet colormap with smoothed steps

Params:

• wcol, optional: color of “white”
• other options are passed to cmap_smoothed_regular_steps()

Sample:

cmap_wr(name='vacumm_wr', **kwargs)

White->red colormap

Sample:

cmap_wre(name='vacumm_wre', **kwargs)

White->red->yellow colormap for positive extremes

Sample:

cmaps_gmt(names=True)

List available GMT colormaps

See also:cmap_gmt() print_cmaps_gmt() get_cmap()

cmaps_mpl(vacumm=True, gmt=True, names=True)

List available registered colormaps available directly from Matplotlib

See also:get_cmap()

cmaps_registered(include=None, exclude=None, names=True)

List colormap registered in matplotlib

Params:

• include: Include only colormaps that have one of these prefixes.
• include: Exclude colormaps that have one of these prefixes.
• names: Return names OR colormaps.

cmaps_vacumm(names=True)

List available VACUMM colormaps

See also:get_cmap()

darken(c, f)

Darken a color ‘c’ by a factor ‘f’ (max when f=1)

Params:

• c: Color
• f: Factor between 0 and 1 with null impact at 0

Sample:

>>> darken('r',0)
(1.0, 0.0, 0.0)
>>> darken('r',.5)
(0.5, 0.0, 0.0)

See also:

whiten()

decimaitre = (0.9609375, 0.87109375, 0.703125)

Alias for land color

desaturate(c, f)

Desaturate a color or a colormap

discretise_cmap(cmap, bounds, name=None, **kwargs)

Make discret an existing colormap

Examples:

>>> discretise_cmap('jet', [.25, .5, .9]) # two not evenly spaced colors
>>> discretise_cmap('jet', 10) # ten evenly spaced colors

Params:

• cmap: Colormap.
• bounds: An array of limits that will normalized. If a scalar, it is converted into an array of ‘scalar’ values ranging from 0 to 1.
• name, optional: Name of the colormap.
• Other params are passed to cmap_custom().

get_cmap(cmap=None, errmode=None, **kwargs)

A simple way to get a VACUMM, GMT or MPL colormap

Example:

>>> get_cmap('jet')         # Matplotlib
>>> pylab.jet()             # Matplotlib
>>> pylab.get_cmap('jet')   # Matplotlib
>>> get_cmap('cmap_grey',start=.2)   # VACUMM
>>> get_cmap('vacumm_grey')   # VACUMM (registered in MPL)
>>> cmap_grey(start=.2)     # VACUMM
>>> get_cmap('gmt_gebco')   # GMT (registered in MPL)
>>> cmap_gmt('gebco')       # GMT (registered in MPL)

See also:

cmap_gmt() matplotlib.pyplot.get_cmap()

jean_pierre = (0.9609375, 0.87109375, 0.703125)

Alias for land color

land = (0.9609375, 0.87109375, 0.703125)

Alias for land color

ocean = (0.6, 0.8, 1)

Ocean color

pastelise(c, s=0.25, v=0.9)

Make a color more pastel

Equivalent to:

>>> c = change_value(c, v)
>>> c = change_saturation(c, s)

plot_cmap(cmap, ncol=None, smoothed=True, ax=None, figsize=(5, 0.25), fig=None, show=True, aspect=0.05, title=None, title_loc=(0.5, 0.5), sa={'bottom': 0.0, 'left': 0.0, 'right': 1, 'top': 1}, savefig=None, savefigs=None, close=True, **kwargs)

Display a colormap

plot_cmaps(cmaps=None, figsize=None, show=True, savefig=None, ncol=5, savefigs=None, aspect=0.05, fig=None, close=True, **kwargs)

Display a list of or all colormaps

print_cmaps_gmt()

List available gmt colormaps

See also:cmap_gmt() cmaps_gmt() get_cmap()

rainbow(n=None, mode='auto', first=None, last=None, middle=None, stretcher=None)

Get a list of nice rainbow colors

Params:

• n, optional: Number of requested colors. It should be > 1. Defaults to None

• mode, optional: Mode for choosing extreme colors.

  • "strict": Blue and red are first and last colors.
  • "first": (.5, 0, 1) is inserted as first color.
  • "last": (1, 0, .5) is inserted as last color.
  • "auto" or None: Switch to "extended" if n>6.
  • "extended" or anything else: Like "first" and "last".

• stretcher, optional: Function that alter color steps from their range [0.->1.] to [0.->1.]. This must be used for example to enhance a part of the colormap. Its value may also be a predefined function:

  • "reduced_green": Shrink the green band.

  Note

  This function must return a monotonic array of increasing values included in the [0,1] interval.

saturate(c, f)

Saturate a color or a colormap

sea = (0.6, 0.8, 1)

Alias for ocean color

show_cmap(cmap, *args, **kwargs)

Alias for plot_cmap()

simple_colors = ['k', 'b', 'g', 'r', 'c', 'm', 'y']

Basic list of colors

to_grey(c, f, g=0.5)

Pull a color toward a single grey vzlue

Params:

• c: Color
• f: Factor between 0 and 1. When max, color is converted to medium grey (“0.5”).
• g: Value of the grey

Sample:

>>> to_grey('r', 0)
(1.0, 0.0, 0.0)
>>> to_grey('r',1)
(0.5, 0.5, 0.5)

See also:

whiten() : darken()

to_shadow(c, att=0.3)

Return the shadow color of a color

Note

This is a simple shortcut to darken() with f=.3 be default.

Params:

• c: Color.
• att, optional: Attenuation factor

whiten(c, f)

Whiten a color ‘c’ by a factor ‘f’ (max when f=1)

Params:

• c: Color
• f: Factor between 0 and 1 with null impact at 0

Sample:

>>> whiten('r',.5)
(1.0, 0.5, 0.5)
>>> whiten('r',0)
(1.0, 0.0, 0.0)

See also:

darken()