Esempio n. 1
0
File: plot.py Progetto: TonioF/cate
def plot_contour(ds: xr.Dataset,
                 var: VarName.TYPE,
                 time: TimeLike.TYPE = None,
                 indexers: DictLike.TYPE = None,
                 title: str = None,
                 filled: bool = True,
                 properties: DictLike.TYPE = None,
                 file: str = None) -> Figure:
    """
    Create a contour plot of a variable given by dataset *ds* and variable name *var*.

    :param ds: the dataset containing the variable to plot
    :param var: the variable's name
    :param time: time slice index to plot, can be a string "YYYY-MM-DD" or an integer number
    :param indexers: Optional indexers into data array of *var*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "layer=4".
    :param title: an optional title
    :param filled: whether the regions between two contours shall be filled
    :param properties: optional plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5), label='Sea Surface Temperature'"
           For full reference refer to
           https://matplotlib.org/api/lines_api.html and
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Patch.html#matplotlib.patches.Patch
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    var_name = VarName.convert(var)
    if not var_name:
        raise ValidationError("Missing name for 'var'")
    var = ds[var_name]

    time = TimeLike.convert(time)
    indexers = DictLike.convert(indexers) or {}
    properties = DictLike.convert(properties) or {}

    figure = plt.figure(figsize=(8, 4))
    ax = figure.add_subplot(111)

    var_data = get_var_data(var, indexers, time=time)
    if filled:
        var_data.plot.contourf(ax=ax, **properties)
    else:
        var_data.plot.contour(ax=ax, **properties)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 2
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def plot_hist(ds: xr.Dataset,
              var: VarName.TYPE,
              indexers: DictLike.TYPE = None,
              title: str = None,
              properties: DictLike.TYPE = None,
              file: str = None) -> Figure:
    """
    Plot a variable, optionally save the figure in a file.

    The plot can either be shown using pyplot functionality, or saved,
    if a path is given. The following file formats for saving the plot
    are supported: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg,
    svgz, tif, tiff

    :param ds: Dataset that contains the variable named by *var*.
    :param var: The name of the variable to plot
    :param indexers: Optional indexers into data array of *var*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "lon=12.6, layer=3, time='2012-05-02'".
    :param title: an optional title
    :param properties: optional histogram plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5), label='Sea Surface Temperature'"
           For full reference refer to
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.pyplot.hist.html and
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Patch.html#matplotlib.patches.Patch
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    var_name = VarName.convert(var)
    if not var_name:
        raise ValidationError("Missing name for 'var'")

    var = ds[var]

    indexers = DictLike.convert(indexers)
    properties = DictLike.convert(properties) or {}

    figure = plt.figure(figsize=(8, 4))
    ax = figure.add_subplot(111)
    figure.tight_layout()

    var_data = get_var_data(var, indexers)
    var_data.plot.hist(ax=ax, **properties)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 3
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def plot_hist(ds: xr.Dataset,
              var: VarName.TYPE,
              indexers: DictLike.TYPE = None,
              title: str = None,
              properties: DictLike.TYPE = None,
              file: str = None) -> Figure:
    """
    Plot a variable, optionally save the figure in a file.

    The plot can either be shown using pyplot functionality, or saved,
    if a path is given. The following file formats for saving the plot
    are supported: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg,
    svgz, tif, tiff

    :param ds: Dataset that contains the variable named by *var*.
    :param var: The name of the variable to plot
    :param indexers: Optional indexers into data array of *var*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "lon=12.6, layer=3, time='2012-05-02'".
    :param title: an optional title
    :param properties: optional histogram plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5), label='Sea Surface Temperature'"
           For full reference refer to
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.pyplot.hist.html and
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Patch.html#matplotlib.patches.Patch
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    var_name = VarName.convert(var)
    if not var_name:
        raise ValidationError("Missing name for 'var'")

    var = ds[var]

    indexers = DictLike.convert(indexers)
    properties = DictLike.convert(properties) or {}

    figure = plt.figure(figsize=(8, 4))
    ax = figure.add_subplot(111)
    figure.tight_layout()

    var_data = get_var_data(var, indexers)
    var_data.plot.hist(ax=ax, **properties)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 4
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def plot_contour(ds: xr.Dataset,
                 var: VarName.TYPE,
                 indexers: DictLike.TYPE = None,
                 title: str = None,
                 filled: bool = True,
                 properties: DictLike.TYPE = None,
                 file: str = None) -> Figure:
    """
    Create a contour plot of a variable given by dataset *ds* and variable name *var*.

    :param ds: the dataset containing the variable to plot
    :param var: the variable's name
    :param indexers: Optional indexers into data array of *var*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "layer=4".
    :param title: an optional title
    :param filled: whether the regions between two contours shall be filled
    :param properties: optional plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5), label='Sea Surface Temperature'"
           For full reference refer to
           https://matplotlib.org/api/lines_api.html and
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Patch.html#matplotlib.patches.Patch
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    var_name = VarName.convert(var)
    if not var_name:
        raise ValidationError("Missing name for 'var'")
    var = ds[var_name]

    indexers = DictLike.convert(indexers) or {}
    properties = DictLike.convert(properties) or {}

    figure = plt.figure(figsize=(8, 4))
    ax = figure.add_subplot(111)

    var_data = get_var_data(var, indexers)
    if filled:
        var_data.plot.contourf(ax=ax, **properties)
    else:
        var_data.plot.contour(ax=ax, **properties)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 5
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def plot(ds: DatasetLike.TYPE,
         var: VarName.TYPE,
         indexers: DictLike.TYPE = None,
         title: str = None,
         properties: DictLike.TYPE = None,
         file: str = None) -> Figure:
    """
    Create a 1D/line or 2D/image plot of a variable given by dataset *ds* and variable name *var*.

    :param ds: Dataset or Dataframe that contains the variable named by *var*.
    :param var: The name of the variable to plot
    :param indexers: Optional indexers into data array of *var*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "lat=12.4, time='2012-05-02'".
    :param title: an optional plot title
    :param properties: optional plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5), label='Sea Surface Temperature'"
           For full reference refer to
           https://matplotlib.org/api/lines_api.html and
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Patch.html#matplotlib.patches.Patch
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    ds = DatasetLike.convert(ds)

    var_name = VarName.convert(var)
    if not var_name:
        raise ValidationError("Missing name for 'var'")
    var = ds[var_name]

    indexers = DictLike.convert(indexers)
    properties = DictLike.convert(properties) or {}

    figure = plt.figure()
    ax = figure.add_subplot(111)

    var_data = get_var_data(var, indexers)
    var_data.plot(ax=ax, **properties)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 6
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def plot_data_frame(df: pd.DataFrame,
                    plot_type: str = 'line',
                    file: str = None,
                    **kwargs) -> Figure:
    """
    Plot a data frame.
    This is a wrapper of pandas.DataFrame.plot() function.
    For further documentation please see
    http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.plot.html
    :param df: A pandas dataframe to plot
    :param plot_type: Plot type
    :param file: path to a file in which to save the plot
    :param kwargs: Keyword arguments to pass to the underlying
                   pandas.DataFrame.plot function
    """
    if not isinstance(df, pd.DataFrame):
        raise ValidationError('"df" must be of type "pandas.DataFrame"')

    ax = df.plot(kind=plot_type, figsize=(8, 4), **kwargs)
    figure = ax.get_figure()
    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 7
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def plot_data_frame(df: pd.DataFrame,
                    plot_type: str = 'line',
                    file: str = None,
                    **kwargs) -> Figure:
    """
    Plot a data frame.
    This is a wrapper of pandas.DataFrame.plot() function.
    For further documentation please see
    http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.plot.html
    :param df: A pandas dataframe to plot
    :param plot_type: Plot type
    :param file: path to a file in which to save the plot
    :param kwargs: Keyword arguments to pass to the underlying
                   pandas.DataFrame.plot function
    """
    if not isinstance(df, pd.DataFrame):
        raise ValidationError('"df" must be of type "pandas.DataFrame"')

    ax = df.plot(kind=plot_type, figsize=(8, 4), **kwargs)
    figure = ax.get_figure()
    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 8
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def plot_hovmoeller(ds: xr.Dataset,
                    var: VarName.TYPE = None,
                    x_axis: DimName.TYPE = None,
                    y_axis: DimName.TYPE = None,
                    method: str = 'mean',
                    contour: bool = True,
                    title: str = None,
                    file: str = None,
                    monitor: Monitor = Monitor.NONE,
                    **kwargs) -> Figure:
    """
    Create a Hovmoeller plot of the given dataset. Dimensions other than
    the ones defined as x and y axis will be aggregated using the given
    method to produce the plot.

    :param ds: Dataset to plot
    :param var: Name of the variable to plot
    :param x_axis: Dimension to show on x axis
    :param y_axis: Dimension to show on y axis
    :param method: Aggregation method
    :param contour: Whether to produce a contour plot
    :param title: Plot title
    :param file: path to a file in which to save the plot
    :param monitor: A progress monitor
    :param kwargs: Keyword arguments to pass to underlying xarray plotting fuction
    """
    var_name = None
    if not var:
        for key in ds.data_vars.keys():
            var_name = key
            break
    else:
        var_name = VarName.convert(var)
    var = ds[var_name]

    if not x_axis:
        x_axis = var.dims[0]
    else:
        x_axis = DimName.convert(x_axis)

    if not y_axis:
        try:
            y_axis = var.dims[1]
        except IndexError:
            raise ValidationError('Given dataset variable should have at least two dimensions.')
    else:
        y_axis = DimName.convert(y_axis)

    if x_axis == y_axis:
        raise ValidationError('Dimensions should differ between plot axis.')

    dims = list(var.dims)
    try:
        dims.remove(x_axis)
        dims.remove(y_axis)
    except ValueError:
        raise ValidationError('Given dataset variable: {} does not feature requested dimensions:\
 {}, {}.'.format(var_name, x_axis, y_axis))

    ufuncs = {'min': np.nanmin, 'max': np.nanmax, 'mean': np.nanmean,
              'median': np.nanmedian, 'sum': np.nansum}

    with monitor.starting("Plot Hovmoeller", total_work=100):
        monitor.progress(5)
        with monitor.child(90).observing("Aggregate"):
            var = var.reduce(ufuncs[method], dim=dims)
        monitor.progress(5)

    figure = plt.figure()
    ax = figure.add_subplot(111)
    if x_axis == 'time':
        figure.autofmt_xdate()

    if contour:
        var.plot.contourf(ax=ax, x=x_axis, y=y_axis, **kwargs)
    else:
        var.plot.pcolormesh(ax=ax, x=x_axis, y=y_axis, **kwargs)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 9
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def plot_scatter(ds1: xr.Dataset,
                 ds2: xr.Dataset,
                 var1: VarName.TYPE,
                 var2: VarName.TYPE,
                 indexers1: DictLike.TYPE = None,
                 indexers2: DictLike.TYPE = None,
                 type: str = '2D Histogram',
                 title: str = None,
                 properties: DictLike.TYPE = None,
                 file: str = None) -> Figure:
    """
    Create a scatter plot of two variables of two variables given by datasets *ds1*, *ds2* and the
    variable names *var1*, *var2*.

    :param ds1: Dataset that contains the variable named by *var1*.
    :param ds2: Dataset that contains the variable named by *var2*.
    :param var1: The name of the first variable to plot
    :param var2: The name of the second variable to plot
    :param indexers1: Optional indexers into data array *var1*. The *indexers1* is a dictionary
           or comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "lat=12.4, time='2012-05-02'".
    :param indexers2: Optional indexers into data array *var2*.
    :param type: The plot type.
    :param title: optional plot title
    :param properties: optional plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5), label='Sea Surface Temperature'"
           For full reference refer to
           https://matplotlib.org/api/lines_api.html and
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Patch.html#matplotlib.patches.Patch
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    var_name1 = VarName.convert(var1)
    var_name2 = VarName.convert(var2)
    indexers1 = DictLike.convert(indexers1) or {}
    indexers2 = DictLike.convert(indexers2) or {}
    properties = DictLike.convert(properties) or {}

    datasets = ds1, ds2
    var_names = var_name1, var_name2
    vars = [None, None]
    for i in (0, 1):
        try:
            vars[i] = datasets[i][var_names[i]]
        except KeyError as e:
            raise ValidationError(f'"{var_names[i]}" is not a variable in dataset given by "ds{i+1}"') from e

    var_dim_names = set(vars[0].dims), set(vars[1].dims)
    indexer_dim_names = set(indexers1.keys()), set(indexers2.keys())

    if set(var_dim_names[0]).isdisjoint(var_dim_names[1]):
        raise ValidationError('"var1" and "var2" have no dimensions in common:'
                              f' {var_dim_names[0]} and {var_dim_names[1]}.')

    for i in (0, 1):
        if indexer_dim_names[i] and not (indexer_dim_names[i] < var_dim_names[i]):
            raise ValidationError(f'"indexers{i+1}" must be a subset of the dimensions of "var{i+1}",'
                                  f' but {indexer_dim_names[i]} is not a subset of {var_dim_names[i]}.')

    rem_dim_names1 = var_dim_names[0] - indexer_dim_names[0]
    rem_dim_names2 = var_dim_names[1] - indexer_dim_names[1]
    if rem_dim_names1 != rem_dim_names2:
        raise ValidationError('Remaining dimensions of data from "var1" must be equal to'
                              f' remaining dimensions of data from "var2",'
                              f' but {rem_dim_names1} is not equal to {rem_dim_names2}.'
                              ' You may need to use the indexers correctly.')

    indexers = indexers1, indexers2
    labels = [None, None]
    for i in (0, 1):
        # Note, long_name can be really long, too long.
        # name = vars[i].attrs.get('long_name', var_names[i])
        name = var_names[i]
        units = vars[i].attrs.get('units', '-')
        labels[i] = f'{name} ({units})'
        if indexers[i]:
            try:
                vars[i] = vars[i].sel(method='nearest', **indexers[i])
            except (KeyError, ValueError, TypeError) as e:
                raise ValidationError(f'"indexers{i+1}" is not valid for "var{i+1}": {e}') from e
            labels[i] += " at " + ",".join(f"{key} = {value}" for key, value in indexers[i].items())

    shape1 = vars[0].shape
    shape2 = vars[1].shape
    if shape1 != shape2:
        raise ValidationError('Remaining shape of data from "var1" must be equal to'
                              ' remaining shape of data from "var2",'
                              f' but {shape1} is not equal to {shape2}.'
                              ' You may need to use the "coregister" operation first.')

    figure = plt.figure(figsize=(8, 8))
    ax = figure.add_subplot(111)

    try:
        x = vars[0].values.flatten()
        y = vars[1].values.flatten()
    except MemoryError as e:
        raise ValidationError('Out of memory. Try using a data subset'
                              ' or specify indexers to reduce number of dimensions.') from e

    default_cmap = 'Reds'

    if type == 'Point':
        ax.grid(color='grey', linestyle='-', linewidth=0.25, alpha=0.5)
        if 'alpha' not in properties:
            properties['alpha'] = 0.25
        if 'markerfacecolor' not in properties:
            properties['markerfacecolor'] = '#880000'
        if 'markeredgewidth' not in properties:
            properties['markeredgewidth'] = 0.0
        if 'markersize' not in properties:
            properties['markersize'] = 5.0
        ax.plot(x, y, '.', **properties)
    elif type == '2D Histogram':
        if 'cmap' not in properties:
            properties['cmap'] = default_cmap
        if 'bins' not in properties:
            properties['bins'] = (256, 256)
        if 'norm' not in properties:
            properties['norm'] = matplotlib.colors.LogNorm()
        if 'range' not in properties:
            xrange = np.nanpercentile(x, [0, 100])
            yrange = np.nanpercentile(y, [0, 100])
            properties['range'] = [xrange, yrange]
        h, xedges, yedges, pc = ax.hist2d(x, y, **properties)
        figure.colorbar(pc, ax=ax, cmap=properties['cmap'])
    elif type == 'Hexbin':
        if 'cmap' not in properties:
            properties['cmap'] = default_cmap
        if 'gridsize' not in properties:
            properties['gridsize'] = (64, 64)
        if 'norm' not in properties:
            properties['norm'] = matplotlib.colors.LogNorm()
        x = np.ma.masked_invalid(x, copy=False)
        y = np.ma.masked_invalid(y, copy=False)
        collection = ax.hexbin(x, y, **properties)
        figure.colorbar(collection, ax=ax, cmap=properties['cmap'])

    ax.set_xlabel(labels[0])
    ax.set_ylabel(labels[1])

    if title:
        ax.set_title(title)

    # see https://matplotlib.org/tutorials/intermediate/tight_layout_guide.html
    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 10
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def plot_line(ds: DatasetLike.TYPE,
              var_names: VarNamesLike.TYPE,
              fmt: str = None,
              label: DimName.TYPE = None,
              indexers: DictLike.TYPE = None,
              title: str = None,
              file: str = None) -> Figure:
    """
    Create a 1D/line plot of variable(s) given by dataset *ds* and variable name(s) *var_names*.

    :param ds: Dataset or Dataframe that contains the variable(s) named by *var_names*.
    :param var_names: The name of the variable(s) to plot
    :param fmt: optional semicolon-separated matplotlib formats,
           e.g.
           1 variable - "b.-"
           2 variables - "b.-;r+:"
           If the number of properties is less than the number of selected variables, the next non-corresponding
           variable will repeat the first style on the list, and so on.
           For full reference on matplotlib plot() function, refer to
           https://matplotlib.org/api/_as_gen/matplotlib.pyplot.plot.html
    :param file: path to a file in which to save the plot
    :param label: dimension name to be selected as the x-axis of the plot
    :param indexers: Optional indexers into data array of *var_names*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "lat=12.4, time='2012-05-02'".
    :param title: an optional plot title
    :return: a matplotlib figure object or None if in IPython mode
    """
    ds = DatasetLike.convert(ds)

    fmt_count = 0
    fmt_list = []

    if fmt:
        fmt_list = fmt.split(";")
        fmt_count = len(fmt_list)

    if not var_names:
        raise ValidationError("Missing name for 'vars'")

    figure = plt.figure()
    ax = figure.add_subplot(111)
    figure.subplots_adjust(right=0.65)

    var_names = VarNamesLike.convert(var_names)
    if not title:
        if label:
            title = ','.join(var_names) + ' over ' + label
        else:
            title = ','.join(var_names)
    if indexers:
        title = title + '\n' + ' at ' + json.dumps(indexers).strip('"')
    ax.set_title(title)

    indexers = DictLike.convert(indexers)

    ax_var = {}
    var_count = len(var_names)
    predefined_fmt = ['r', 'g', 'b', 'c', 'm', 'y', 'k']
    if label:
        ds = get_vars_data(ds, indexers, remaining_dims=[label])
    else:
        ds = get_vars_data(ds, indexers)

    for i in range(var_count):
        var_name = var_names[i]
        var = ds[var_name]
        if len(var.dims) > 1:
            raise ValidationError(f'Unable to plot because variable {var_name} has more than one dimension: {var.dims}.'
                                  f' To specify value(s) of these dimension(s), please use the indexers.')

        var_label = var_name + ' (' + var.attrs['units'] + ')' if 'units' in var.attrs else var_name
        properties_dict = {}

        indexers = DictLike.convert(indexers)

        if fmt is None:
            selected_fmt = predefined_fmt[i % len(predefined_fmt)]
        else:
            selected_fmt = fmt_list[i % fmt_count]

        if label:
            x_axis = var[label]
        elif 'time' in var:
            x_axis = var.time
        else:
            x_axis = []
        # to differentiate the creation of y-axis of the first and the nth variable
        if i == 0:
            if len(x_axis) > 0:
                ax.plot(x_axis, var, selected_fmt, **properties_dict)
            else:
                ax.plot(var, selected_fmt, **properties_dict)
            ax.set_ylabel(var_label, wrap=True)
            ax.yaxis.label.set_color(selected_fmt[0])
            ax.tick_params(axis='y', colors=selected_fmt[0])
        else:
            ax_var[var_name] = ax.twinx()
            if len(ax_var) > 1:
                ax_var[var_name].spines["right"].set_position(("axes", 1 + ((i - 1) * 0.2)))
                ax_var[var_name].set_frame_on(True)
                ax_var[var_name].patch.set_visible(False)
            if len(x_axis) > 0:
                ax_var[var_name].plot(x_axis, var, selected_fmt, **properties_dict)
            else:
                ax_var[var_name].plot(var, selected_fmt, **properties_dict)
            ax_var[var_name].set_ylabel(var_label, wrap=True)
            ax_var[var_name].yaxis.label.set_color(selected_fmt[0])
            ax_var[var_name].tick_params(axis='y', colors=selected_fmt[0])

    ax.tick_params(axis='x', rotation=45)
    if label in ds and 'long_name' in ds[label].attrs:
        ax.set_xlabel(ds[label].attrs['long_name'])
    figure.tight_layout()

    if file:
        figure.savefig(file, dpi=600)

    return figure if not in_notebook() else None
Esempio n. 11
0
File: plot.py Progetto: TonioF/cate
def plot_scatter(ds1: xr.Dataset,
                 ds2: xr.Dataset,
                 var1: VarName.TYPE,
                 var2: VarName.TYPE,
                 indexers1: DictLike.TYPE = None,
                 indexers2: DictLike.TYPE = None,
                 title: str = None,
                 properties: DictLike.TYPE = None,
                 file: str = None) -> Figure:
    """
    Create a scatter plot of two variables of two variables given by datasets *ds1*, *ds2* and the
    variable names *var1*, *var2*.

    :param ds1: Dataset that contains the variable named by *var1*.
    :param ds2: Dataset that contains the variable named by *var2*.
    :param var1: The name of the first variable to plot
    :param var2: The name of the second variable to plot
    :param indexers1: Optional indexers into data array *var1*. The *indexers1* is a dictionary
           or comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "lat=12.4, time='2012-05-02'".
    :param indexers2: Optional indexers into data array *var2*.
    :param title: optional plot title
    :param properties: optional plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5), label='Sea Surface Temperature'"
           For full reference refer to
           https://matplotlib.org/api/lines_api.html and
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Patch.html#matplotlib.patches.Patch
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    var_name1 = VarName.convert(var1)
    var_name2 = VarName.convert(var2)
    if not var_name1:
        raise ValidationError("Missing name for 'var1'")
    if not var_name2:
        raise ValidationError("Missing name for 'var2'")
    var1 = ds1[var_name1]
    var2 = ds2[var_name2]

    indexers1 = DictLike.convert(indexers1) or {}
    indexers2 = DictLike.convert(indexers2) or {}
    properties = DictLike.convert(properties) or {}

    try:
        if indexers1:
            var_data1 = var1.sel(method='nearest', **indexers1)
            if not indexers2:
                indexers2 = indexers1

            var_data2 = var2.sel(method='nearest', **indexers2)
            remaining_dims = list(set(var1.dims) ^ set(indexers1.keys()))
            min_dim = max(var_data1[remaining_dims[0]].min(), var_data2[remaining_dims[0]].min())
            max_dim = min(var_data1[remaining_dims[0]].max(), var_data2[remaining_dims[0]].max())
            var_data1 = var_data1.where((var_data1[remaining_dims[0]] >= min_dim) &
                                        (var_data1[remaining_dims[0]] <= max_dim),
                                        drop=True)
            var_data2 = var_data2.where(
                (var_data2[remaining_dims[0]] >= min_dim) & (var_data2[remaining_dims[0]] <= max_dim),
                drop=True)
            if len(remaining_dims) is 1:
                indexer3 = {remaining_dims[0]: var_data1[remaining_dims[0]].data}
                var_data2.reindex(method='nearest', **indexer3)
            else:
                raise ValidationError('Please use indexers to reduce the dimensionality of each variable to one.')
        else:
            var_data1 = var1
            var_data2 = var2
    except ValueError:
        var_data1 = var1
        var_data2 = var2

    figure = plt.figure(figsize=(12, 8))
    ax = figure.add_subplot(111)

    # var_data1.plot(ax = ax, **properties)
    ax.plot(var_data1.values, var_data2.values, '.', **properties)
    # var_data1.plot(ax=ax, **properties)
    xlabel_txt = "".join(", " + str(key) + " = " + str(value) for key, value in indexers1.items())
    xlabel_txt = var_name1 + xlabel_txt
    ylabel_txt = "".join(", " + str(key) + " = " + str(value) for key, value in indexers2.items())
    ylabel_txt = var_name2 + ylabel_txt
    ax.set_xlabel(xlabel_txt)
    ax.set_ylabel(ylabel_txt)
    figure.tight_layout()

    if title:
        ax.set_title(title)

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 12
0
def plot_hovmoeller(ds: xr.Dataset,
                    var: VarName.TYPE = None,
                    x_axis: DimName.TYPE = None,
                    y_axis: DimName.TYPE = None,
                    method: str = 'mean',
                    contour: bool = True,
                    title: str = None,
                    file: str = None,
                    monitor: Monitor = Monitor.NONE,
                    **kwargs) -> Figure:
    """
    Create a Hovmoeller plot of the given dataset. Dimensions other than
    the ones defined as x and y axis will be aggregated using the given
    method to produce the plot.

    :param ds: Dataset to plot
    :param var: Name of the variable to plot
    :param x_axis: Dimension to show on x axis
    :param y_axis: Dimension to show on y axis
    :param method: Aggregation method
    :param contour: Whether to produce a contour plot
    :param title: Plot title
    :param file: path to a file in which to save the plot
    :param monitor: A progress monitor
    :param kwargs: Keyword arguments to pass to underlying xarray plotting fuction
    """
    var_name = None
    if not var:
        for key in ds.data_vars.keys():
            var_name = key
            break
    else:
        var_name = VarName.convert(var)
    var = ds[var_name]

    if not x_axis:
        x_axis = var.dims[0]
    else:
        x_axis = DimName.convert(x_axis)

    if not y_axis:
        try:
            y_axis = var.dims[1]
        except IndexError:
            raise ValidationError(
                'Given dataset variable should have at least two dimensions.')
    else:
        y_axis = DimName.convert(y_axis)

    if x_axis == y_axis:
        raise ValidationError('Dimensions should differ between plot axis.')

    dims = list(var.dims)
    try:
        dims.remove(x_axis)
        dims.remove(y_axis)
    except ValueError:
        raise ValidationError(
            'Given dataset variable: {} does not feature requested dimensions:\
 {}, {}.'.format(var_name, x_axis, y_axis))

    ufuncs = {
        'min': np.nanmin,
        'max': np.nanmax,
        'mean': np.nanmean,
        'median': np.nanmedian,
        'sum': np.nansum
    }

    with monitor.starting("Plot Hovmoeller", total_work=100):
        monitor.progress(5)
        with monitor.child(90).observing("Aggregate"):
            var = var.reduce(ufuncs[method], dim=dims)
        monitor.progress(5)

    figure = plt.figure()
    ax = figure.add_subplot(111)
    if x_axis == 'time':
        figure.autofmt_xdate()

    if contour:
        var.plot.contourf(ax=ax, x=x_axis, y=y_axis, **kwargs)
    else:
        var.plot.pcolormesh(ax=ax, x=x_axis, y=y_axis, **kwargs)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 13
0
def plot_scatter(ds1: xr.Dataset,
                 ds2: xr.Dataset,
                 var1: VarName.TYPE,
                 var2: VarName.TYPE,
                 indexers1: DictLike.TYPE = None,
                 indexers2: DictLike.TYPE = None,
                 type: str = '2D Histogram',
                 title: str = None,
                 properties: DictLike.TYPE = None,
                 file: str = None) -> Figure:
    """
    Create a scatter plot of two variables of two variables given by datasets *ds1*, *ds2* and the
    variable names *var1*, *var2*.

    :param ds1: Dataset that contains the variable named by *var1*.
    :param ds2: Dataset that contains the variable named by *var2*.
    :param var1: The name of the first variable to plot
    :param var2: The name of the second variable to plot
    :param indexers1: Optional indexers into data array *var1*. The *indexers1* is a dictionary
           or comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "lat=12.4, time='2012-05-02'".
    :param indexers2: Optional indexers into data array *var2*.
    :param type: The plot type.
    :param title: optional plot title
    :param properties: optional plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5), label='Sea Surface Temperature'"
           For full reference refer to
           https://matplotlib.org/api/lines_api.html and
           https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Patch.html#matplotlib.patches.Patch
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    var_name1 = VarName.convert(var1)
    var_name2 = VarName.convert(var2)
    indexers1 = DictLike.convert(indexers1) or {}
    indexers2 = DictLike.convert(indexers2) or {}
    properties = DictLike.convert(properties) or {}

    datasets = ds1, ds2
    var_names = var_name1, var_name2
    vars = [None, None]
    for i in (0, 1):
        try:
            vars[i] = datasets[i][var_names[i]]
        except KeyError as e:
            raise ValidationError(
                f'"{var_names[i]}" is not a variable in dataset given by "ds{i+1}"'
            ) from e

    var_dim_names = set(vars[0].dims), set(vars[1].dims)
    indexer_dim_names = set(indexers1.keys()), set(indexers2.keys())

    if set(var_dim_names[0]).isdisjoint(var_dim_names[1]):
        raise ValidationError('"var1" and "var2" have no dimensions in common:'
                              f' {var_dim_names[0]} and {var_dim_names[1]}.')

    for i in (0, 1):
        if indexer_dim_names[i] and not (indexer_dim_names[i] <
                                         var_dim_names[i]):
            raise ValidationError(
                f'"indexers{i+1}" must be a subset of the dimensions of "var{i+1}",'
                f' but {indexer_dim_names[i]} is not a subset of {var_dim_names[i]}.'
            )

    rem_dim_names1 = var_dim_names[0] - indexer_dim_names[0]
    rem_dim_names2 = var_dim_names[1] - indexer_dim_names[1]
    if rem_dim_names1 != rem_dim_names2:
        raise ValidationError(
            'Remaining dimensions of data from "var1" must be equal to'
            f' remaining dimensions of data from "var2",'
            f' but {rem_dim_names1} is not equal to {rem_dim_names2}.'
            ' You may need to use the indexers correctly.')

    indexers = indexers1, indexers2
    labels = [None, None]
    for i in (0, 1):
        # Note, long_name can be really long, too long.
        # name = vars[i].attrs.get('long_name', var_names[i])
        name = var_names[i]
        units = vars[i].attrs.get('units', '-')
        labels[i] = f'{name} ({units})'
        if indexers[i]:
            try:
                vars[i] = vars[i].sel(method='nearest', **indexers[i])
            except (KeyError, ValueError, TypeError) as e:
                raise ValidationError(
                    f'"indexers{i+1}" is not valid for "var{i+1}": {e}') from e
            labels[i] += " at " + ",".join(
                f"{key} = {value}" for key, value in indexers[i].items())

    shape1 = vars[0].shape
    shape2 = vars[1].shape
    if shape1 != shape2:
        raise ValidationError(
            'Remaining shape of data from "var1" must be equal to'
            ' remaining shape of data from "var2",'
            f' but {shape1} is not equal to {shape2}.'
            ' You may need to use the "coregister" operation first.')

    figure = plt.figure(figsize=(8, 8))
    ax = figure.add_subplot(111)

    try:
        x = vars[0].values.flatten()
        y = vars[1].values.flatten()
    except MemoryError as e:
        raise ValidationError(
            'Out of memory. Try using a data subset'
            ' or specify indexers to reduce number of dimensions.') from e

    default_cmap = 'Reds'

    if type == 'Point':
        ax.grid(color='grey', linestyle='-', linewidth=0.25, alpha=0.5)
        if 'alpha' not in properties:
            properties['alpha'] = 0.25
        if 'markerfacecolor' not in properties:
            properties['markerfacecolor'] = '#880000'
        if 'markeredgewidth' not in properties:
            properties['markeredgewidth'] = 0.0
        if 'markersize' not in properties:
            properties['markersize'] = 5.0
        ax.plot(x, y, '.', **properties)
    elif type == '2D Histogram':
        if 'cmap' not in properties:
            properties['cmap'] = default_cmap
        if 'bins' not in properties:
            properties['bins'] = (256, 256)
        if 'norm' not in properties:
            properties['norm'] = matplotlib.colors.LogNorm()
        if 'range' not in properties:
            xrange = np.nanpercentile(x, [0, 100])
            yrange = np.nanpercentile(y, [0, 100])
            properties['range'] = [xrange, yrange]
        h, xedges, yedges, pc = ax.hist2d(x, y, **properties)
        figure.colorbar(pc, ax=ax, cmap=properties['cmap'])
    elif type == 'Hexbin':
        if 'cmap' not in properties:
            properties['cmap'] = default_cmap
        if 'gridsize' not in properties:
            properties['gridsize'] = (64, 64)
        if 'norm' not in properties:
            properties['norm'] = matplotlib.colors.LogNorm()
        x = np.ma.masked_invalid(x, copy=False)
        y = np.ma.masked_invalid(y, copy=False)
        collection = ax.hexbin(x, y, **properties)
        figure.colorbar(collection, ax=ax, cmap=properties['cmap'])

    ax.set_xlabel(labels[0])
    ax.set_ylabel(labels[1])

    if title:
        ax.set_title(title)

    # see https://matplotlib.org/tutorials/intermediate/tight_layout_guide.html
    figure.tight_layout()

    if file:
        figure.savefig(file)

    return figure if not in_notebook() else None
Esempio n. 14
0
def plot_line(ds: DatasetLike.TYPE,
              var_names: VarNamesLike.TYPE,
              fmt: str = None,
              label: DimName.TYPE = None,
              indexers: DictLike.TYPE = None,
              title: str = None,
              file: str = None) -> Figure:
    """
    Create a 1D/line plot of variable(s) given by dataset *ds* and variable name(s) *var_names*.

    :param ds: Dataset or Dataframe that contains the variable(s) named by *var_names*.
    :param var_names: The name of the variable(s) to plot
    :param fmt: optional semicolon-separated matplotlib formats,
           e.g.
           1 variable - "b.-"
           2 variables - "b.-;r+:"
           If the number of properties is less than the number of selected variables, the next non-corresponding
           variable will repeat the first style on the list, and so on.
           For full reference on matplotlib plot() function, refer to
           https://matplotlib.org/api/_as_gen/matplotlib.pyplot.plot.html
    :param file: path to a file in which to save the plot
    :param label: dimension name to be selected as the x-axis of the plot
    :param indexers: Optional indexers into data array of *var_names*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "lat=12.4, time='2012-05-02'".
    :param title: an optional plot title
    :return: a matplotlib figure object or None if in IPython mode
    """
    ds = DatasetLike.convert(ds)

    fmt_count = 0
    fmt_list = []

    if fmt:
        fmt_list = fmt.split(";")
        fmt_count = len(fmt_list)

    if not var_names:
        raise ValidationError("Missing name for 'vars'")

    figure = plt.figure()
    ax = figure.add_subplot(111)
    figure.subplots_adjust(right=0.65)

    var_names = VarNamesLike.convert(var_names)
    if not title:
        if label:
            title = ','.join(var_names) + ' over ' + label
        else:
            title = ','.join(var_names)
    if indexers:
        title = title + '\n' + ' at ' + json.dumps(indexers).strip('"')
    ax.set_title(title)

    indexers = DictLike.convert(indexers)

    ax_var = {}
    var_count = len(var_names)
    predefined_fmt = ['r', 'g', 'b', 'c', 'm', 'y', 'k']
    if label:
        ds = get_vars_data(ds, indexers, remaining_dims=[label])
    else:
        ds = get_vars_data(ds, indexers)

    for i in range(var_count):
        var_name = var_names[i]
        var = ds[var_name]
        if len(var.dims) > 1:
            raise ValidationError(
                f'Unable to plot because variable {var_name} has more than one dimension: {var.dims}.'
                f' To specify value(s) of these dimension(s), please use the indexers.'
            )

        var_label = var_name + ' (' + var.attrs[
            'units'] + ')' if 'units' in var.attrs else var_name
        properties_dict = {}

        indexers = DictLike.convert(indexers)

        if fmt is None:
            selected_fmt = predefined_fmt[i % len(predefined_fmt)]
        else:
            selected_fmt = fmt_list[i % fmt_count]

        if label:
            x_axis = var[label]
        elif 'time' in var:
            x_axis = var.time
        else:
            x_axis = []
        # to differentiate the creation of y-axis of the first and the nth variable
        if i == 0:
            if len(x_axis) > 0:
                ax.plot(x_axis, var, selected_fmt, **properties_dict)
            else:
                ax.plot(var, selected_fmt, **properties_dict)
            ax.set_ylabel(var_label, wrap=True)
            ax.yaxis.label.set_color(selected_fmt[0])
            ax.tick_params(axis='y', colors=selected_fmt[0])
        else:
            ax_var[var_name] = ax.twinx()
            if len(ax_var) > 1:
                ax_var[var_name].spines["right"].set_position(
                    ("axes", 1 + ((i - 1) * 0.2)))
                ax_var[var_name].set_frame_on(True)
                ax_var[var_name].patch.set_visible(False)
            if len(x_axis) > 0:
                ax_var[var_name].plot(x_axis, var, selected_fmt,
                                      **properties_dict)
            else:
                ax_var[var_name].plot(var, selected_fmt, **properties_dict)
            ax_var[var_name].set_ylabel(var_label, wrap=True)
            ax_var[var_name].yaxis.label.set_color(selected_fmt[0])
            ax_var[var_name].tick_params(axis='y', colors=selected_fmt[0])

    ax.tick_params(axis='x', rotation=45)
    if label in ds and 'long_name' in ds[label].attrs:
        ax.set_xlabel(ds[label].attrs['long_name'])
    figure.tight_layout()

    if file:
        figure.savefig(file, dpi=600)

    return figure if not in_notebook() else None
Esempio n. 15
0
def plot_map(ds: xr.Dataset,
             var: VarName.TYPE = None,
             indexers: DictLike.TYPE = None,
             region: PolygonLike.TYPE = None,
             projection: str = 'PlateCarree',
             central_lon: float = 0.0,
             title: str = None,
             contour_plot: bool = False,
             properties: DictLike.TYPE = None,
             file: str = None) -> object:
    """
    Create a geographic map plot for the variable given by dataset *ds* and variable name *var*.

    Plots the given variable from the given dataset on a map with coastal lines.
    In case no variable name is given, the first encountered variable in the
    dataset is plotted. In case no *time* is given, the first time slice
    is taken. It is also possible to set extents of the plot. If no extents
    are given, a global plot is created.

    The plot can either be shown using pyplot functionality, or saved,
    if a path is given. The following file formats for saving the plot
    are supported: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg,
    svgz, tif, tiff

    :param ds: the dataset containing the variable to plot
    :param var: the variable's name
    :param indexers: Optional indexers into data array of *var*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "layer=4".
    :param region: Region to plot
    :param projection: name of a global projection, see http://scitools.org.uk/cartopy/docs/v0.15/crs/projections.html
    :param central_lon: central longitude of the projection in degrees
    :param title: an optional title
    :param contour_plot: If true plot a filled contour plot of data, otherwise plots a pixelated colormesh
    :param properties: optional plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5)"
           For full reference refer to
           https://matplotlib.org/api/lines_api.html and
           https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.contourf.html
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    if not isinstance(ds, xr.Dataset):
        raise ValidationError('Only gridded datasets are currently supported.')

    var_name = None
    if not var:
        for key in ds.data_vars.keys():
            var_name = key
            break
    else:
        var_name = VarName.convert(var)
    var = ds[var_name]

    indexers = DictLike.convert(indexers) or {}
    properties = DictLike.convert(properties) or {}

    extents = None
    bounds = handle_plot_polygon(region)
    if bounds:
        lon_min, lat_min, lon_max, lat_max = bounds
        extents = [lon_min, lon_max, lat_min, lat_max]

    if len(ds.lat) < 2 or len(ds.lon) < 2:
        # Matplotlib can not plot datasets with less than these dimensions with
        # contourf and pcolormesh methods
        raise ValidationError(
            'The minimum dataset spatial dimensions to create a map'
            ' plot are (2,2)')

    # See http://scitools.org.uk/cartopy/docs/v0.15/crs/projections.html#
    if projection == 'PlateCarree':
        proj = ccrs.PlateCarree(central_longitude=central_lon)
    elif projection == 'LambertCylindrical':
        proj = ccrs.LambertCylindrical(central_longitude=central_lon)
    elif projection == 'Mercator':
        proj = ccrs.Mercator(central_longitude=central_lon)
    elif projection == 'Miller':
        proj = ccrs.Miller(central_longitude=central_lon)
    elif projection == 'Mollweide':
        proj = ccrs.Mollweide(central_longitude=central_lon)
    elif projection == 'Orthographic':
        proj = ccrs.Orthographic(central_longitude=central_lon)
    elif projection == 'Robinson':
        proj = ccrs.Robinson(central_longitude=central_lon)
    elif projection == 'Sinusoidal':
        proj = ccrs.Sinusoidal(central_longitude=central_lon)
    elif projection == 'NorthPolarStereo':
        proj = ccrs.NorthPolarStereo(central_longitude=central_lon)
    elif projection == 'SouthPolarStereo':
        proj = ccrs.SouthPolarStereo(central_longitude=central_lon)
    else:
        raise ValidationError('illegal projection: "%s"' % projection)

    figure = plt.figure(figsize=(8, 4))
    ax = plt.axes(projection=proj)
    if extents:
        ax.set_extent(extents, ccrs.PlateCarree())
    else:
        ax.set_global()

    ax.coastlines()
    var_data = get_var_data(var, indexers, remaining_dims=('lon', 'lat'))

    # transform keyword is for the coordinate our data is in, which in case of a
    # 'normal' lat/lon dataset is PlateCarree.
    if contour_plot:
        var_data.plot.contourf(ax=ax,
                               transform=ccrs.PlateCarree(),
                               subplot_kws={'projection': proj},
                               **properties)
    else:
        var_data.plot.pcolormesh(ax=ax,
                                 transform=ccrs.PlateCarree(),
                                 subplot_kws={'projection': proj},
                                 **properties)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        try:
            figure.savefig(file)
        except MemoryError:
            raise MemoryError(
                'Not enough memory to save the plot. Try using a different file format'
                ' or enabling contour_plot.')

    return figure if not in_notebook() else ax
Esempio n. 16
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 def test_nominal(self):
     """
     Nominal test
     """
     self.assertFalse(in_notebook())
Esempio n. 17
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 def test_nominal(self):
     """
     Nominal test
     """
     self.assertFalse(in_notebook())
Esempio n. 18
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def plot_map(ds: xr.Dataset,
             var: VarName.TYPE = None,
             indexers: DictLike.TYPE = None,
             region: PolygonLike.TYPE = None,
             projection: str = 'PlateCarree',
             central_lon: float = 0.0,
             title: str = None,
             contour_plot: bool = False,
             properties: DictLike.TYPE = None,
             file: str = None) -> object:
    """
    Create a geographic map plot for the variable given by dataset *ds* and variable name *var*.

    Plots the given variable from the given dataset on a map with coastal lines.
    In case no variable name is given, the first encountered variable in the
    dataset is plotted. In case no *time* is given, the first time slice
    is taken. It is also possible to set extents of the plot. If no extents
    are given, a global plot is created.

    The plot can either be shown using pyplot functionality, or saved,
    if a path is given. The following file formats for saving the plot
    are supported: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg,
    svgz, tif, tiff

    :param ds: the dataset containing the variable to plot
    :param var: the variable's name
    :param indexers: Optional indexers into data array of *var*. The *indexers* is a dictionary
           or a comma-separated string of key-value pairs that maps the variable's dimension names
           to constant labels. e.g. "layer=4".
    :param region: Region to plot
    :param projection: name of a global projection, see http://scitools.org.uk/cartopy/docs/v0.15/crs/projections.html
    :param central_lon: central longitude of the projection in degrees
    :param title: an optional title
    :param contour_plot: If true plot a filled contour plot of data, otherwise plots a pixelated colormesh
    :param properties: optional plot properties for Python matplotlib,
           e.g. "bins=512, range=(-1.5, +1.5)"
           For full reference refer to
           https://matplotlib.org/api/lines_api.html and
           https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.contourf.html
    :param file: path to a file in which to save the plot
    :return: a matplotlib figure object or None if in IPython mode
    """
    if not isinstance(ds, xr.Dataset):
        raise ValidationError('Only gridded datasets are currently supported.')

    var_name = None
    if not var:
        for key in ds.data_vars.keys():
            var_name = key
            break
    else:
        var_name = VarName.convert(var)
    var = ds[var_name]

    indexers = DictLike.convert(indexers) or {}
    properties = DictLike.convert(properties) or {}

    extents = None
    bounds = handle_plot_polygon(region)
    if bounds:
        lon_min, lat_min, lon_max, lat_max = bounds
        extents = [lon_min, lon_max, lat_min, lat_max]

    if len(ds.lat) < 2 or len(ds.lon) < 2:
        # Matplotlib can not plot datasets with less than these dimensions with
        # contourf and pcolormesh methods
        raise ValidationError('The minimum dataset spatial dimensions to create a map'
                              ' plot are (2,2)')

    # See http://scitools.org.uk/cartopy/docs/v0.15/crs/projections.html#
    if projection == 'PlateCarree':
        proj = ccrs.PlateCarree(central_longitude=central_lon)
    elif projection == 'LambertCylindrical':
        proj = ccrs.LambertCylindrical(central_longitude=central_lon)
    elif projection == 'Mercator':
        proj = ccrs.Mercator(central_longitude=central_lon)
    elif projection == 'Miller':
        proj = ccrs.Miller(central_longitude=central_lon)
    elif projection == 'Mollweide':
        proj = ccrs.Mollweide(central_longitude=central_lon)
    elif projection == 'Orthographic':
        proj = ccrs.Orthographic(central_longitude=central_lon)
    elif projection == 'Robinson':
        proj = ccrs.Robinson(central_longitude=central_lon)
    elif projection == 'Sinusoidal':
        proj = ccrs.Sinusoidal(central_longitude=central_lon)
    elif projection == 'NorthPolarStereo':
        proj = ccrs.NorthPolarStereo(central_longitude=central_lon)
    elif projection == 'SouthPolarStereo':
        proj = ccrs.SouthPolarStereo(central_longitude=central_lon)
    else:
        raise ValidationError('illegal projection: "%s"' % projection)

    figure = plt.figure(figsize=(8, 4))
    ax = plt.axes(projection=proj)
    if extents:
        ax.set_extent(extents, ccrs.PlateCarree())
    else:
        ax.set_global()

    ax.coastlines()
    var_data = get_var_data(var, indexers, remaining_dims=('lon', 'lat'))

    # transform keyword is for the coordinate our data is in, which in case of a
    # 'normal' lat/lon dataset is PlateCarree.
    if contour_plot:
        var_data.plot.contourf(ax=ax, transform=ccrs.PlateCarree(), subplot_kws={'projection': proj}, **properties)
    else:
        var_data.plot.pcolormesh(ax=ax, transform=ccrs.PlateCarree(), subplot_kws={'projection': proj}, **properties)

    if title:
        ax.set_title(title)

    figure.tight_layout()

    if file:
        try:
            figure.savefig(file)
        except MemoryError:
            raise MemoryError('Not enough memory to save the plot. Try using a different file format'
                              ' or enabling contour_plot.')

    return figure if not in_notebook() else ax