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• the land coloured in grey
• the sea coloured as #dcf0ff

Plotting the Mean Sea Level Pressure field

Plot the GRIB file sandy_msl.grib into this view using a new Contouring icon. Plot black isolines with an interval of 5 hPa between them.

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The fields you visualised were taken from the model run at 2012-10-27 0UTC and containing 12 hourly forecast steps from 0 to 120 hours.

Plotting the storm track

The storm track data is stored in the CSV file called 'sandy_track.txt'. If you open this file you will see that it contains the date, time and geographical coordinates of the track points.

Create a new Table Reader Table table Visualiser icon and set it to visualise your CSV file:

• set the plot type to geo points
• select the columns holding the latitude and longitude by their index
• carefully specify the table delimiter and header information like this

TABLE_DELIMITER = ' '   //it means whitespace. In the editor do not type in the quotes it just press whitespace
TABLE_COMBINE_DELIMITERS = ON
TABLE_HEADER_ROW = 0

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• by setting
  • table_delimiter to whitespace ()
  • table_combine_delimiters to on
  • table header_row to 0

Now drag your Table Visualiser icon the map plot to overlay the track with the mean sea level forecast.

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The storm track in its current for form does not look great so you need to customise it with a Graph Plotting icon by setting the

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To finalise the track plot you need to plot add the date/time labels next to the track points. This can be done with a Symbol Plotting icon by specifying the list of labels you want to plot into the map. Since it would require too much editing you will learn a better (programatic) way of doing it programatically  by using Metview Macro,.

Create new Macro and edit it. First, read the CSV file in with theTable the Table Reader (see its documentation here):

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Here variable tbl contains all the columns from the CSV file. Now read the date and time (from the first two columns) into separate vectors:

val_date=values(tbl,1)
val_time=values(tbl,2)

Next, you need to build the list of labels. Each label is made up from a day and and a an hour part separated by a slash. Use this loop to construct the list:

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Finally, define a Symbol Plotting icon to plot the text labels and return it.

sym = msymb(
	symbol_type	:	"text",
	symbol_text_font_colour : "black",
	symbol_text_font_size: "0.3",
	symbol_text_font_style: "bold",
	symbol_text_list	:	labels	
	)

return [sym]

This visualmdefini  When you use the text mode it will plot By returning the visual definition you built Macro behaves as if it were a real Symbol Plotting icon. So once the Macro is finished drag it into the plot and you should see the labels appearing along the track.

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