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Overview

You have seen already how to either visualise your processed data on the display or save it to a file. Most processing you will do with Metview will lead to a visualisation you might want to save, either to publish it on web pages or in reports, or simply to keep records. This session will give you more information on how you can save and customise your visualisations.

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All graphical output formats are generated through ECMWF's graphics library Magics. This means that all graphical capabilities in Metview depend on what Magics offers. Detailed descriptions of the output formats and their settings can be found in the Magics reference documentation.

The table below gives you a list of all the formats that Magics/Metview support and how you can use them.

The KML output format

KML is a very special output format. It has no notion of output size since it is displayed on the globe. KMZ is the compressed version of the KML files and is written by default. You can write out the uncompressed KML if you want to debug the output.

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The following piece of code shows the simplest way to save your plot as a PostScript PDF file instead of creating an interactive Display Window.

# set up the output format

 ps pdf = pspdf_output(
      output_name : "my_plot"
)
setoutput(pspdf)


data = read("z500.grib")
plot(data)  #  the plot will be sent to the PostScriptPDF file

Try it!

The pspdf_output() function defines how a PostScript PDF file should be generated. More options are available to further customise it. The setoutput() function selects this output format. So our code can contain many output format definitions and then select just one (or more) with the setoutput() function at run-time (see later).

The following code example shows how to set multiple output formats at the same time and also set various parameters for the different output formats. Note that in most cases the default values are sufficient. A list of all options can found in the Magics documentation for each format at: PostScript, SVG, PNG and KML.

#
# Setting common output options for multiple formats
#
output_common = ( 
      output_name            : "/tmp/myOutputTest",   # specify relative or full path
      output_title           : "Map of Z500",        # title used by a viewer
      output_debug           : "ON",                 # print extra information
      output_filelist        : "ON",                 # save list of files generated
      output_filelist_name   : "/tmp/filelist.txt"   # where to save the list
)

ps = ps_output(
      output_common,
      output_ps_scale        : 0.9,    # scale content to 90%, for some printers
      output_ps_colour_model : "CMYK"  # set colour model to CYMK
)

png = png_output(
      output_common,
      output_width           : 1000,                 # set width in pixels
      output_cairo_transparent_background : "ON"  # to get transparent PNGs
)

svg = svg_output(
      output_common,
      output_width        : 1000,                 # set width in pixels
      output_svg_fix_size : "ON",   # this fixes the size to 'output_width'
      output_svg_meta     : "Metview map of Z500",
      output_svg_desc     : "This file was generated for the Training course"
)

kml = kml_output(
      output_common,
      kml_description : "This file was generated for the Training course",
      kml_author      : "Stephan Siemen",
      kml_link        : "http://www.ecmwf.int",
      kml_latitude    : 30,     # latitude where Google Earth centres the view
      kml_longitude   : 120,    # longitude where Google Earth centres the view
      kml_coastlines  : "ON"    # normally OFF"
)

output_drivers = [ps, png, svg, kml]

setoutput(output_drivers)

data = read("z500.grib")

plot(data)

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Of course you can do further processing of plots outside Metview. The page Generating animated GIFs from Metview plots gives you some helpful advice if you want to build animations.

Metview/Magics also supports special tags in SVG for the Inkscape graphical editor. This open source editor is great for when you need to further annotate your maps.

Image RemovedImage Added

If you have extra time

If you have time, you might want to try opening your SVG file from the first exercise above in inkscape and alter it and save it to a PNG.

Using Web Map Services (WMS)

Metview provides a module to request maps from a Web Map Services (WMS). The WMS standard is defined by the Open Geospatial Consortium (OGC), which is very popular in the GIS community. The WMS module can be used to query an OGC-compliant WMS server, retrieve maps from it and overlay them with other data. The WMS icon is a great way to integrate web services within Metview. 

We have a separate tutorial which shows in more detail how you can use maps served by web map services within Metview.

Tasks

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