MetPy - ContourPlot()#

This class is designed to plot contours of gridded data, most commonly model output from the GFS, NAM, or RAP.

ContourPlot()#

Attribute

Description

clabels

A boolean (True/False) on whether to plot contour labels.

contours

A list of values to contour or an integer number of contour levels.

data

Xarray dataset that contains the field to be plotted.

field

Name of the field to be plotted.

label_fontsize

An integer, float, or string value to set the font size of labels for contours.

latitude

The latitude coordinate of the field to be plotted.

level

The level of the field to be plotted.

linecolor

A string value to set the color of plotted contours; default is black.

linestyle

A string value to set the linestyle (e.g., dashed), or None; default is None, which, when using monochrome line colors, uses solid lines for positive values and dashed lines for negative values.

linewidth

An integer value to set the width of plotted contours; default value is 2.

longitude

The longitude coordinate of the field to be plotted.

name

Generate a name for the plot.

plot_units

The desired units to plot the field in.

scale

Scale the field to be plotted by the value given.

smooth_contour

Spline interpolation to smooth contours.

smooth_field

Number of smoothing passes using 9-pt smoother.

time

Set the valid time to be plotted as a datetime object.

mpl_args

Supply a dictionary of valid Matplotlib keyword arguments to modify how the plot variable is drawn.

Attribute Descriptions#

data#

  • This attribute must be set with the variable name that contains the xarray dataset. (Typically this is the variable ds)

field#

  • This attribute must be set with the name of the variable that you want to contour. For example, to plot the heights of pressure surfaces from the GFS you would use the name ‘Geopotential_height_isobaric’

level#

  • This attribute sets the level of the data you wish to plot. If it is a pressure level, then it must be set to a unit bearing value (e.g., 500*units.hPa). If the variable does not have any vertical levels (e.g., mean sea-level pressure), then the level attribute must be set to None.

time#

  • This attribute must be set with a datetime object, just as with the PlotObs() class. To get a forecast hour, you can use the timedelta function from datetime to add the number of hours into the future you wish to plot. For example, if you wanted the six hour forecast from the 00 UTC 2 February 2020 model run, then you would set the attribute with:

    datetime(2020, 2, 2, 0) + timedelta(hours=6)

contours#

  • This attribute sets the contour values to be plotted with a list. This can be set manually with a list of integers in square brackets (e.g., [5400, 5460, 5520, 5580, 5640, 5700]) or programmatically (e.g., range(0, 10000, 60)). The second method is a way to easily set a contour interval (in this case 60).

clabels#

  • This attribute can be set to True if you desire to have your contours labeled.

linestyle#

  • This attribute can be set to make the contours ‘solid’, ‘dashed’, ‘dotted’, or ‘dashdot’.

    Default is ‘solid’.

linewidth#

  • This attribute alters the width of the contours (defaults to 1). Setting the value greater than 1 will yield a thicker contour line.

linecolor#

  • This attribute sets the color of the contour lines. Default is ‘black’. All colors from matplotlib are valid.

plot_units#

  • If you want to change the units for plotting purposes, add the string value of the units desired. For example, if you want to plot temperature in Celsius, then set this attribute to ‘degC’.

smooth_contour#

  • This attribute is best used to smooth contours when contouring a sparse grid (e.g., when your data has a large grid spacing). This will produce smoothed geopotential heights for all levels available in the DataArray using a spline interpolation.

smooth_field#

  • This attribute is best used to smooth contours when contouring a higher resolution (smaller grid spacing with lots of grid points) field. This will produce a smoothed field using the nine-point smoother twice.

mpl_args#

  • This attribute can be set to a dictionary containing keyword arguments (kwarg) valid for the various Matplotlib plotting functions to enhance how a plot is created. For example, you can use this attribute to set the zorder kwarg to alter what aspects of the your plot are on top of one another. NOTE: Setting the mpl_args trait will override any other trait that corresponds to a specific kwarg for the particular plot type (e.g., linecolor, linewidth).