| Scroll pdf ignore | ||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Creating and Editing an Icon
This session follows on from uses the same t1000.grib data file as A Simple Visualisation. We will work ; a copy of that file already exists in the same folder, so make sure you have already downloaded the files from that folder for this session.
Metview uses icons to control the various aspects of a plot's appearance. We will look at some of these now.
Let’s customise , starting with the coastline plotting attributes.
First, create a new Coastlines icon. You can right-click within the Metview desktop to obtain a context menu from where the option Create new icon is available (shortcut: CTRL-N).
...
Changing the Map Projection and Storing the Area
Metview's default map projection is Cylindrical. However, meteorologists often use other projections when plotting data.
...
Use the Zoom tools to enlarge the European area and use the Area tool to select a region over Europe. Click Ok to save your selection - your choices will now be updated in the Geographical View editor. Click Apply in the Geographical View editor to save everything. Plot your data in this view to confirm that the area and projection are as desired.
Linking the Coastlines icon with the Geographical View Icon
...
This says, "In the polar_europe view, plot data t1000". Your complete macro should look like this:
...
Contour Shade | On |
Contour Shade Method | Area Fill |
Contour Shade Max Level Colour | Red |
Contour Shade Min Level Colour | Blue |
Contour Shade Colour Direction | Clockwise |
Apply the changes, visualise the data icon again (visualise t1000.grb) again and drag the shade icon into the Display Window.
...
Now when you apply this icon you will see that the palette is fixed wherever you zoom. There will probably be parts of the plot which are not filled; this is because our range of contour levels does not cover the whole range of values in the data. Change the list of contour levels so that the whole plot will be covered - you only need to add one number to each end of the level list to do this (or else change the current numbers at the ends of the list).
Updating the Macro
Edit your macro icon again and drop the fixed_t icon into the editor, aiming the drop so that the code is generated above the plot() command. The code to generate the contouring specification will appear, assigned to the variable fixed_t (the variable is always named after the icon that was dropped). Add this to the end of the plot command:
...