mhovmoellerview
Defines the view for Hovmoeller diagram plots from a suitable GRIB data source. It can also take the output from a Hovmoeller data object (mhovmoeller_area()
, mhovmoeller_line()
or mhovmoeller_vertical()
) as an input. In this case, a consistency check is performed between the parameters that are common to both functions.
In addition to the parameters required for the Hovmoeller diagram computation, mhovmoellerview()
specifies the axis details as well as the plot positioning in the plot frame of the display window/paper sheet and the overlay of different data units in the same plot.
To access the computed output values use a Hovmoeller data object.
For further details on the role and usage of views in the visualisation process, please see Anaylis Views.
Note
See also mhovmoeller_area()
, mhovmoeller_line()
, mhovmoeller_vertical()
and mhovmoeller_expand()
.
Note
This function performs the same task as the Hovmoeller View icon in Metview’s user interface. It accepts its parameters as keyword arguments, described below.
- mhovmoellerview(**kwargs)
Defines the view for Hovmoeller diagram plots.
- Parameters
type ({"line_hovm", "area_hovm", "vertical_hovm"}, default: "line_hovm") –
Specifies the type of the Hovmoeller diagram to be produced. Options are:
”area_hovm”: diagram derived from an input rectangular area
”line_hovm”: diagram derived from an input transect line.
”vertical_hovm”: diagram derived from an input rectangular area and a set of levels.
input_mode ({"point", "nearest_gridpoint", "area"}, default: "area") –
Defines the horizontal data selection method for vertical Hovmoeller diagrams. Enabled when
type
is “vertical_hovm”. The possible options are as follows:”point”: the data is interpolated to the location specified by
point
”nearest_gridpoint”: the nearest gridpoint to the location specified by
point
is extracted”area”: the values inside the
area
are averaged usingintegrate()
New in Metview version 5.16.0
point (list[number], default: [0, 0]) – Specifies the coordinates (as [lat, lon]) of the point for which the vertical Hovmoeller is computed. Enabled when
type
is “vertical_hovm” andinput_mode
is “point” or “nearest_gridpoint”. New in Metview version 5.16.0line (list[number], default: [0, -180, 0, 180]) – Specifies the coordinates of a transect line along which the Hovmoeller diagram is calculated in [lat1, lon1, lat2, lon2] format. Enabled when
type
is “line_hovm”.area (list[number], default: [30, -30, -30, 30]) – Specifies the coordinates of the area (as [north, west, south, east]) over which the Hovmoeller diagram is calculated. Enabled when
type
is “area_hovm” or “vertical_hovm” (andinput_mode
is “area”).area_statistics ({"mean", "minimum", "maximum", "stdev", "variance", "median"}, default: "mean") –
Specifies the type of computation performed in the
area
:when
type
is “area_hovm” it is a computation along theaverage_direction
. For “mean”, “stdev” or “variance” whenaverage_direction
is “north_south” the aggregation is weighted by the cosine of the latitudes.when
type
is “vertical_hovm” andinput_mode
is “area” it is a computation performed on all the gridpoints in thearea
. For “mean”, “stdev” or “variance” the aggregation is weighted by the cosine of the latitudes.
Enabled when
type
is “area_hovm” or “vertical_hovm” (andinput_mode
is “area”). New in Metview version 5.18.0average_direction ({"east_west", "north_south"}, default: "east_west") – Specifies the direction along which the computation defined in
area_statistics
is performed. When it is “north_south” andarea_statistics
is “average”, “stdev” or “variance” the aggregation is weighted by the cosine of the latitudes. Enabled whentype
is “area_hovm”.time_axis_mode ({"automatic_forwards", "automatic_backwards", "user"}, default: "user") –
Specifies the direction of the date/time axis. The options are as follows:
”user”: left/bottom date is taken from
date_min
and the right/top date is taken fromdate_max
.”automatic_forwards”: date limits are taken from the data and plotted left to right or bottom to top.
”automatic_backwards”: date limits are taken from the data and plotted right to left or top to bottom. This option has the same effect as “user” with default
date_min
anddate_max
.
date_min (str, default: "automatic") – Specifies the horizontal date minimum value. Default value “automatic” indicates that the minimum value will be taken from the input data.
date_max (str, default: "automatic") – Specifies the horizontal date maximum value. Default value “automatic” indicates that the maximum value will be taken from the input data.
bottom_level (number, default: 1015.0) – Specifies the lower (closest to the surface) limit of the Hovmoeller data in the units of the vertical coordinates. Only levels in the range defined by
top_level
andbottom_level
are included in the output data. An extra level on either side of this range is also added. Only used for vertical Hovmoeller diagrams (type
is “vertical_hovm”) whenvertical_level_type
is “pressure” or “param”.top_level (number, default: 0.01) – Specifies the upper (furthest from the surface) limit of the Hovmoeller data in the units of the vertical coordinates. Only levels in the range defined by
top_level
andbottom_level
are included in the output data. An extra level on either side of this range is also added. Only used for vertical Hovmoeller diagrams (type
is “vertical_hovm”) whenvertical_level_type
is “pressure” or “param”.swap_axes ({"no", "yes"}, default: "no") – By default, the definition of the vertical and horizontal axes of the Hovmoeller diagrams follows pre-defined rules. However, if
swap_axes
is set to “yes” then the axes will be swapped around.resolution (number, default: 1.0) – Used to interpolate the data onto a regular grid, and applies to both the horizontal and vertical axes where appropriate. This parameter is essential for creating a Hovmoeller diagram from satellite data.
time_axis (
maxis()
) –Specifies the characteristics of the time-series axis as an
maxis()
object to be used in the plotting of the data. The followingmaxis()
parameters are defined by the application; therefore, users should not change their values directly:axis_type
(set to “date”),axis_date_min_value
andaxis_date_max_value
(set according todate_min
anddate_max
, respectively), andaxis_orientation
. Theaxis_orientation
parameter is defined according to the following rules:if
type
is “line_hovm”, the value is set to “horizontal”.if
type
is “area_hovm” and average_direction` is “east_west”, the value is set to “horizontal”.if
type
is “area_hovm” andaverage_direction
is “north_south”, the value is set to “vertical”.if
type
is “vertical_hovm”, the value is set to “horizontal”.
However, it is possible to change
axis_orientation
value from its calculated default by settingswap_axes
to “yes”. This option is not available for “vertical_hovm”.geo_axis (
maxis()
) –Specifies the characteristics of the geographical axis as an
maxis()
object to be used in the plotting of the data. The followingmaxis()
parameters are defined by the application; therefore, users should not change their values directly:axis_min_value
andaxis_max_value
(set according toline
orarea
),axis_type
,axis_tick_label_type
andaxis_orientation
. Theaxis_type
andaxis_tick_label_type
parameters are defined according to the following rules:if
type
is “line_hovm”,axis_type
is set to “geoline”.if
type
is “area_hovm” andaverage_direction
is “east_west”,axis_type
is set to “regular” and “axis_tick_label_type`` to “latitude”.if
type
is “area_hovm” andaverage_direction
is “north_south”,axis_type
is set to “regular” andaxis_tick_label_type
to “longitude”.
Moreover,
axis_orientation
parameter is defined according to the following rules:if
type
is “line_hovm”, the value is set to “vertical”.if
type
is “area_hovm” andaverage_direction
is “east_west”, the value is set to “vertical”.if
type
is “area_hovm” andaverage_direction
is “north_south” the value is set to “horizontal”
However, it is possible to change the
axis_orientation
from its calculated default by settingswap_axes
to “yes”.vertical_axis (
maxis()
) – Specifies the characteristics of the level-series axis to be used in the plotting of the data. The followingmaxis()
parameters are defined by the application; therefore, users should not change their values directly:axis_min_value
andaxis_max_value
(set according to the input data set),axis_type
,axis_tick_label_type
andaxis_orientation
.vertical_level_type ({"as_in_data", "pressure", "user"}, default: "as_in_data") –
Specifies the output vertical level type for vertical Hovmoeller diagrams. Enabled when
type
is “vertical_hovm”. The possible options are as follows:”as_in_data”: the level type of
data
is used. In this casetop_level
andbottom_level
must always be set carefully, since their default values are set for pressure in hPa.”pressure”: indicates that the
data
is defined on ECMWF model levels and the output vertical coordinate should be pressure in hPa. When this option is selected the input data must contain the corresponding Logarithm of Surface Pressure (LNSP) fields, unless a fixed surface pressure is used (seeuse_fixed_surface_pressure
).”user”: the vertical coordinates (both input and output) are defined by the fields of
vertical_coordinate_param
. In this casetop_level
andbottom_level
must always be set carefully, since their default values are set for pressure in hPa. New in Metview version 5.16.0
lnsp_param (number, default: 152) – Specifies the ecCodes paramId used to identify the Logarithm of Surface Pressure (LNSP) in the input data. Only used for vertical Hovmoeller diagrams (
type
is “vertical_hovm”) whenvertical_level_type
is “pressure”.use_fixed_surface_pressure ({"on", "off"}, default: "off") – When it is “on” a fixed surface pressure value will be used in the computations and no LNSP fields have to be specified. Only used for vertical Hovmoeller diagrams (
type
is “vertical_hovm”) whenvertical_level_type
is “pressure”. New in Metview version 5.17.0fixed_surface_pressure (number, default: 1013.25) – Specify the fixed surface pressure value in hPa when
use_fixed_surface_pressure
is “on”. Only used for vertical Hovmoeller diagrams (type
is “vertical_hovm”) whenvertical_level_type
is “pressure”. New in Metview version 5.17.0vertical_coordinate_param (number) – Specifies the ecCodes paramId used to identify the vertical coordinate fields in the input data. Only used for vertical Hovmoeller diagrams (
type
is “vertical_hovm”) whenvertical_level_type
is “user”. New in Metview version 5.16.0vertical_coordinate_extrapolate ({"on", "off"}, default: "off") – Performs and extrapolation for the
top_level
andbottom_level
when the output vertical level range does not contain these levels. Only used for vertical Hovmoeller diagrams (type
is “vertical_hovm”) whenvertical_level_type
is “pressure” or “user”. The purpose is to avoid blank areas in the plot near the bottom ot top. New in Metview version 5.16.0vertical_coordinate_extrapolate_mode ({"constant", "linear"}, default: "constant") – Specifies the extrapolation technique. In “constant” mode the values on the nearest input levels are copied onto the target extrapolated levels. In “linear” mode a linear extrapolation is performed using the nearest two input levels. Enabled when
vertical_coordinate_extrapolate
is “on”. New in Metview version 5.16.0vertical_coordinate_extrapolate_fixed_sign ({"on", "off"}, default: "on") – When
vertical_coordinate_extrapolate_mode
is “on” it controls whether the extrapolated values can differ in sign from the values on the nearest input levels. When it is “on” it prevents e.g. wind components to change sign due to extrapolation. New in Metview version 5.16.0vertical_scaling ({"linear", "log"}, default: "linear") – Specifies the type of the vertical axis .
subpage_clipping ({"on", "off"}, default: "off") – Clips plot to subpage borders.
subpage_x_position (number, default: 12) – Specifies the X offset of the plot from the left side of the plot frame (any subdivision of the display area). This is expressed as a percentage of the X-dimension of the plot frame.
subpage_y_position (number, default: 10) – Specifies the Y offset of the plot from the bottom side of the plot frame (any subdivision of the display area). This is expressed as a percentage of the Y-dimension of the plot frame.
subpage_x_length (number, default: 75) – Specifies the X length of the plot. This is expressed as a percentage of the X-dimension of the plot frame. Hence the sum of this X length plus the X offset cannot exceed 100 (it is advised that it does not exceed 95 since you need some margin on the right for things like axis or map grid labels).
subpage_y_length (number, default: 80) – Same as
subpage_x_length
but for the Y length of the plot.page_frame ({"on", "off"}, default: "off") – Toggles the plotting of a border line around the plot frame.
page_frame_colour (str, default: "charcoal") – Colour of the page frame. Available when
page_frame
is “on”.page_frame_line_style ({"solid", "dot", "dash", "chain_dot", "chain_dash"}, default: "solid") – Line style of the page frame. Available when
page_frame
is “on”.page_frame_thickness (number, default: 2) – Line thickness of the page frame. Available when
page_frame
is “on”.page_id_line ({"on", "off"}, default: "off") – Toggles the plotting of plot identification line.
page_id_line_user_text (str) – Specifies user text to be added to the plot identification line. Only available when
page_id_line
is “on”.subpage_frame ({"on", "off"}, default: "off") – Toggles the plotting of a border line around the plot itself. In most cases you will want this to be left “on”. When “off” the sides of the plot not equipped with axis will not be plotted.
subpage_frame_colour (str, default: "black") – Colour of the subpage frame. Available when
subpage_frame
is “on”.subpage_frame_line_style ({"solid", "dot", "dash", "chain_dot", "chain_dash"}, default: "solid") – Line style of the subpage frame. Available when
subpage_frame
is “on”.subpage_frame_thickness (int, default: 2) – Line thickness of the subpage frame. Available when
subpage_frame
is “on”.subpage_background_colour (str, default: "white") – Specifies the colour of the background of the plot (i.e. not affected by visual definitions like contour shadings or lines).
- Return type
Request