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Views in Metview
A fundamental concept in Metview is the View. A View specifies the following definitions in a Metview plot:
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| Name | Usage (Used for plotting or Plotting specification for) |
|---|---|
| Geographical View | geographic-based data plots (default View) (see also A Quick Tour of Metview) |
| Cartesian View | plots that are not to be displayed on a map (see also Graph Plotting in Metview) |
| Cross Section View | cross section plots |
| Vertical Profile View | vertical profile plots |
| Average View | average (zonal or meridional) cross-section plots |
| Annotation View | text boxes (link) |
| Hovmøller View | Hovmøller diagram plots |
| Thermo View | thermodynamic diagram plots |
The Geographical View 
This is the default View for plotting geographic-based data. This View was discussed previously in A Quick Tour of Metview.
The Cartesian View 
This will be covered in another session: Graph Plotting in Metview.
The Cross Section View 
The Cross Section View icon is a plotting specification for cross section plots along a given arbitrary transect line.
- create a new Cross Section View icon.
- Visualise it and drop the t_fc24.grib icon into the resulting Display Window.
A default cross section along the Equator is generated. This is an alternative way to view your data - instead of a geographical plot for instance.
Inspect the GRIB icon (right-click on it and choose examine) to see the type of input data this View requires ,- it should be gridded data (rather than spherical harmonics) and it should contain fields at multiple vertical levels.
To customise the transect line (coordinates along which the cross-section is calculated), do the following:
- Edit the Cross Section View icon
- change the transect line
- click on the Geography Tool button to bring up an editor (or type the coordinate coordinates by hand).
- Save/OK the changes and re-visualise the data with this new cross section.
Note that you can still drag any valid Contouring icons you may have into the Display Window when visualising a cross section. For instance, apply the given shade icon. You may want to customise it and try different configurations.
The Vertical Profile View 
The Vertical Profile View icon is a plotting specification for vertical profile plots.
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- Save/OK the changes and drag it into the Display Window.
The Average View 
The Average View icon is a plotting specification for average (zonal or meridional) cross-section plots.
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You can use a Contouring icon, e.g. the shade icon, to style the contours of the plotting.
The Annotation View 
This will be covered in another session: Layout in Metview.
The Hovmøller View 
The Hovmoeller View icon is a plotting specification for Hovmøller diagram plots along a specified arbitrary transect line or a rectangular area. The diagram displays a two-dimensional graph with latitude or height as one axis and time as the other.
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As previously, you can use a Contouring icon to style the contours of the plotting.
The Thermo View 
The Thermo View icon is a plotting specification for Thermodynamic diagram plots from a suitable GRIB or BUFR data source. In such a diagram, temperature, humidity (represented by the dew point) and wind values are displayed with respect to pressure.
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Examine the GRIB icon to see the type of input data this View requires. Fields Temperature Temperature and Specific Humidity are mandatory and they will be used to compute the Dew Point parameter. Fieldsets U and V wind components are optional, but if given they will be used to compute the wind vectors. If the data is given in model levels then a Logarithm of Surface Pressure field must be provided too in order to help the conversion to pressure levels fields.
Note that only the Tephigram diagram is currently available, although there are exist other types of thermodynamic diagrams, such as Skew-T, Emagram and Stuve.
To customise the curves displayed in this plot, you can apply (or edit it first) icon vdline. The changes will be applied to both lines. The ability to customise each line individually (temperature and dew point) will be available in the a future release of Metview.
The Wind Plotting icon is the visual definition responsible for specifying how gridded wind vector data is displayed. It controls the plotting of features such as wind arrows and wind flags. 
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- Save/OK the changes and drag it into the Display Window.
Macro example
To demonstrate the use of the View concept in a Macro language, let's create a program to analyse the vertical structure of temperature changes in time. This exercise reads two forecast steps, computes the differences and visualise the result in a cross section view.
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