epygram.fields.H2DVectorField — Horizontal 2-D Vector Field class¶
Contains the class for a Horizontal 2D field.
Plus a function to create a Vector field from 2 scalar fields.
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epygram.fields.H2DVectorField.make_vector_field(fX, fY)[source]¶ Creates a new
epygram.H2DVectorFieldfrom twoepygram.H2DFieldfX, fY representing resp. the X and Y components of the vector in the field geometry.
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class
epygram.fields.H2DVectorField.H2DVectorField(*args, **kwargs)[source]¶ Bases:
epygram.base.FieldHorizontal 2-Dimensions Vector field class.
This is a wrapper to a list of H2DField(s), representing the components of a vector projected on its geometry (the grid axes).
Note
This class is managed by footprint.
- info: Not documented
- priority: PriorityLevel::DEFAULT (rank=1)
Automatic parameters from the footprint:
- comment (
str) - rwd - Not documented, sorry.- Optional. Default is None.
- components (
footprints.stdtypes.FPList) - rxx - List of Fields that each compose a component of the vector.- Optional. Default is FPList::<<as_list:: []>>.
- fid (
footprints.stdtypes.FPDict) - rwx - Not documented, sorry. - processtype (
str) - rxx - Generating process.- Optional. Default is None.
- structure (
str) - rxx - Type of Field geometry.- Values: set([‘H2D’])
- units (
str) - rwd - Not documented, sorry.- Optional. Default is ‘’.
- validity (
epygram.base.FieldValidityList) - rwx - Validity of the field.- Optional. Default is FieldValidityList::<<as_list:: [FieldValidity::<epygram.base.FieldValidity object at 0x7ffa4939b210>]>>.
- vector (
bool) - rxx - Intrinsic vectorial nature of the field.- Values: set([True])
Constructor. See its footprint for arguments.
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attach_components(*components)[source]¶ Attach components of the vector to the VectorField. components must be a series of H2DField.
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compute_direction()[source]¶ Returns a
epygram.H2DFieldwhose data is the direction of the Vector field, in degrees.
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compute_vordiv(divide_by_m=False)[source]¶ Compute vorticity and divergence fields from the vector field.
Parameters: divide_by_m – if True, apply f = f/m beforehand, where m is the map factor.
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data¶ Accessor to the field data.
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getdata(subzone=None, **kwargs)[source]¶ Returns the field data, with 2D shape if the field is not spectral, 1D if spectral, as a tuple with data for each component.
Parameters: subzone – optional, among (‘C’, ‘CI’), for LAM fields only, returns the data resp. on the C or C+I zone. Default is no subzone, i.e. the whole field. Shape of 2D data: (x (0) being the X component, y (1) the Y one)
Rectangular grids:
grid[0,0,x] is SW, grid[-1,-1,x] is NE
grid[0,-1,x] is SE, grid[-1,0,x] is NW
Gauss grids:
grid[0,:Nj,x] is first (Northern) band of latitude, masked after Nj = number of longitudes for latitude j
grid[-1,:Nj,x] is last (Southern) band of latitude (idem).
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getvalue_ij(*args, **kwargs)[source]¶ Returns the value of the different components of the field from indexes.
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getvalue_ll(*args, **kwargs)[source]¶ Returns the value of the different components of the field from coordinates.
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global_shift_center(longitude_shift)[source]¶ Shifts the center of the geometry (and the data accordingly) by longitude_shift (in degrees). longitude_shift has to be a multiple of the grid’s resolution in longitude.
For global RegLLGeometry grids only.
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gp2sp(spectral_geometry=None)[source]¶ Transforms the gridpoint field into spectral space, according to the spectral_geometry mandatorily passed as argument. Replaces data in place.
Parameters: spectral_geometry – instance of SpectralGeometry, actually containing spectral transform subroutine (in in its own gp2sp() method).
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map_factorize(reverse=False)[source]¶ Multiply the field by its map factor.
Parameters: reverse – if True, divide.
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nonzero(subzone=None)[source]¶ Returns the number of non-zero values (whose absolute value > config.epsilon).
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plotanimation(title=u'__auto__', repeat=False, interval=1000, **kwargs)[source]¶ Plot the field with animation with regards to time dimension. Returns a
matplotlib.animation.FuncAnimation.In addition to those specified below, all
plotfield()method arguments can be provided.Parameters: - title – title for the plot. ‘__auto__’ (default) will print the current validity of the time frame.
- repeat – to repeat animation
- interval – number of milliseconds between two validities
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plotfield(over=(None, None), subzone=None, title=None, gisquality=u'i', specificproj=None, zoom=None, use_basemap=None, drawcoastlines=True, drawcountries=True, drawrivers=False, departments=False, boundariescolor=u'0.25', parallels=u'auto', meridians=u'auto', subsampling=1, symbol=u'barbs', symbol_options={u'color': u'k'}, plot_module=True, plot_module_options=None, bluemarble=0.0, background=False, quiverkey=None, quiver_options=None, components_are_projected_on=u'grid', map_factor_correction=True, mask_threshold=None, figsize=None, rcparams=None)[source]¶ Makes a simple plot of the field, with a number of options.
Parameters: - over – to plot the vectors over an existing figure (e.g. colorshades). Any existing figure and/or ax to be used for the plot, given as a tuple (fig, ax), with None for missing objects. fig is the frame of the matplotlib figure, containing eventually several subplots (axes); ax is the matplotlib axes on which the drawing is done. When given (is not None), these objects must be coherent, i.e. ax being one of the fig axes.
- subzone –
among (‘C’, ‘CI’), for LAM fields only, plots the data resp. on the C or C+I zone.
Default is no subzone, i.e. the whole field.
- gisquality – among (‘c’, ‘l’, ‘i’, ‘h’, ‘f’) – by increasing quality. Defines the quality for GIS elements (coastlines, countries boundaries...). Default is ‘i’. Cf. ‘basemap’ doc for more details.
- specificproj –
enables to make basemap on the specified projection, among: ‘kav7’, ‘cyl’, ‘ortho’, (‘nsper’, {...}) (cf. Basemap doc).
In ‘nsper’ case, the {} may contain:
- ‘sat_height’ = satellite height in km;
- ‘lon’ = longitude of nadir in degrees;
- ‘lat’ = latitude of nadir in degrees.
Overwritten by zoom.
- zoom –
specifies the lon/lat borders of the map, implying hereby a ‘cyl’ projection. Must be a dict(lonmin=, lonmax=, latmin=, latmax=).
Overwrites specificproj.
- use_basemap – a basemap.Basemap object used to handle the projection of the map. If given, the map projection options (specificproj, zoom, gisquality ...) are ignored, keeping the properties of the use_basemap object. (because making Basemap is the most time-consuming step).
- drawrivers – to add rivers on map.
- departments – if True, adds the french departments on map (instead of countries).
- boundariescolor – color of lines for boundaries (countries, departments, coastlines)
- drawcoastlines – to add coast lines on map.
- drawcountries – to add countries on map.
- title – title for the plot. Default is field identifier.
- meridians –
enable to fine-tune the choice of lines to plot, with either:
- ‘auto’: automatic scaling to the basemap extents
- ‘default’: range(0,360,10)
- a list of values
- a grid step, e.g. 5 to plot each 5 degree.
- None: no one is plot
- meridian == ‘greenwich’ // ‘datechange’ // ‘greenwich+datechange’ combination (,) will plot only these.
- parallels –
enable to fine-tune the choice of lines to plot, with either:
- ‘auto’: automatic scaling to the basemap extents
- ‘default’: range(-90,90,10)
- a list of values
- a grid step, e.g. 5 to plot each 5 degree.
- None: no one is plot
- ‘equator’ // ‘polarcircles’ // ‘tropics’ or any combination (,) will plot only these.
- subsampling – to subsample the number of gridpoints to plot. Ex: subsampling = 10 will only plot one gridpoint upon 10.
- symbol – among (‘barbs’, ‘arrows’, ‘stream’)
- symbol_options – a dict of options to be passed to barbs or quiver method.
- plot_module – to plot module as colorshades behind vectors.
- plot_module_options – options (dict) to be passed to module.plotfield().
- bluemarble – if > 0.0 (and <=1.0), displays NASA’s “blue marble” as background. The numerical value sets its transparency.
- background – if True, set a background color to continents and oceans.
- quiverkey – to activate quiverkey; must contain arguments to be passed to pyplot.quiverkey(), as a dict.
- components_are_projected_on – inform the plot on which axes the vector components are projected on (‘grid’ or ‘lonlat’).
- map_factor_correction – if True, applies a correction of magnitude to vector due to map factor.
- mask_threshold – dict with min and/or max value(s) to mask outside.
- figsize – figure sizes in inches, e.g. (5, 8.5). Default figsize is config.plotsizes.
- rcparams – list of (*args, **kwargs) to be passed to pyplot.rc() defaults to [((‘font’,), dict(family=’serif’)),]
This method uses (hence requires) ‘matplotlib’ and ‘basemap’ libraries.
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reproject_wind_on_lonlat(map_factor_correction=True, reverse=False)[source]¶ Reprojects a wind vector (u, v) from the grid axes onto real sphere, i.e. with components on true zonal/meridian axes.
Parameters: - map_factor_correction – if True, apply a correction of magnitude due to map factor.
- reverse – if True, apply the reverse reprojection.
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sp2gp()[source]¶ Transforms the spectral field into gridpoint, according to its spectral geometry. Replaces data in place.
The spectral transform subroutine is actually included in the spectral geometry’s sp2gp() method.
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spectral¶ Returns True if the field is spectral.
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what(out=<open file '<stdout>', mode 'w'>, vertical_geometry=True, cumulativeduration=True)[source]¶ Writes in file a summary of the field.
Parameters: - out – the output open file-like object (duck-typing: out.write() only is needed).
- vertical_geometry – if True, writes the vertical geometry of the field.