How to use the Weather Symbol Editor in uPlot?

The Weather Symbol Editor is an experimental feature and is not yet released outside the ECMWF.

At ECMWF you need to use a development Metview version to try out the editor. The command you need to run is as follows:

module swap metview/5.14.0-developmetview

How to start the symbol editor?

Start uPlot and open the sidebar then select the Symbols tab:

How to add a new symbol to the map?

Just click on the symbol in the sidebar, the cursor changes into a cross, then click on the map to add the symbol.

Lines

When you are creating a line double click to conclude the creation.

Polylines, curves and fronts

When you are creating a polyline or a curve each left-click on the map adds a new point and double-click concludes the creation.

What kind of symbol are available?

Fitted geo-shapes

These are special shapes where all the vertices keep their lat-lon positions as the projection changes and the edges between them are sampled linearly in lat-lon space. It means that in cylindrical projection the edges are always straight lines, while in other projections they might be curves. The following table shows how a fitted geo-shape changes as the projection changes from cylindrical to polar north:

Shape	Cylindrical	Polar North
Geo Line
Geo Polyline
Geo Polygon
Geo Quad The corner points always form a rectangle in the lat-lon space.

Geo shapes

In these shapes all the vertices keep their lat-lon positions as the projection changes and they are always connected with a straight line (or with a B-Spline for curves) in all the projections.

The geo rectangle is a special object because it always keeps its rectangular shape. It means that if we zoom the lat-lon positions of the corner points do not change. However, if we change the projection the lat-lon positions of the corners are automatically adjusted so that the shape could be a rectangle in the new projection.

Object	Cylindrical	Polar North
Line
Geo rectangle

Markers and text

For these objects only the anchor point (see below) keeps its lat-lon position as the projection changes, while the extent is defined in terms of pixels:

Object	Cylindrical	Polar North
Text
Placemark

The anchor position depends on the object type:

for a text box it is the top left corner
for a placemark it is the tip of the symbol (bottom-centre)
for the other shapes it is the centre

Surface analysis

This is a collection of standard meteorological curves and symbols.

WMO symbols

All the WMO weather symbols are available here. They behave like markers, i.e. their centre keeps its lat-lon position when the projection changes and the extent is defined in pixels.

Can I add my own symbols?

You can use any square shaped SVG or PNG file as a symbol. These have to be added to the System/Symbols folder in your Metview home directory. When you start a uPlot window it scans this directory and adds all the files with .*svg or *.png suffix to the Markers and text group in the Symbols sidebar.

How can I edit the symbols?

Single click on the symbol: it gets into edit mode where you can move and resize it and edit its graphical properties from the ribbon editor at the top of the view area.

How can I edit the points on a polyline, curve or front?

Double click the symbol and the control points become visible. You can drag them now to a new location.

You can add/remove points to a curve when you are in the point edit mode. Right click on a control point and use the actions in the context menu:

Can I rotate the objects?

It is not yet available.

Is redo-undo available?