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Metview has much functionality for meteorological data types stored in ECMWF's MARS archive, for example GRIB, BUFR and ODB. But not all data comes in these formats. Therefore Metview has facilities to handle various other data types, which we will explore here.
XXXX Download data.
Visualiser Icons
Some formats, such as GRIB, are easy to visualise in Metview - just right-click, Visualise. This is because they are quite constrained in their contents and have enough standardised meta-data for a program to understand how they should be plotted. Some other formats, such as netCDF and tables of ASCII data are not easily interpreted for automatic plotting (which variables/columns should be selected and what do they represent?). Metview introduces the concept of the Visualiser icon, which we will use in some of the following examples.
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Metview uses netCDF internally for the results of some computations. In particular, the analysis views (e.g. Cross Section View, Vertical Profile View) do this, but their result data is not available to the user. Therefore, each of these views has a corresponding Data view. If the intention is to simply plot the result, then the View icons are more useful. But to store the result data, the Data icon is required.
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? Needed? Already covered in the Processing Data part! XXXXXX
Other ASCII Data
ASCII Table Data
Metview incorporates functionality to read, process and visualise data stored in ASCII table files, including the commonly-used CSV (comma-separated value) format.
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The macro can now write this to disk, return it to the user interface or process it further using all the available geopoints functions.
ASCII Lat /
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Lon Matrices
Have a look at the supplied Lat Long Lon Matrix file with the edit action. This is a simple text format for storing regularly-spaced geographical matrix data, which Metview can directly import. As soon as you do anything with this file (e.g. visualise or examine), Metview internally converts it into GRIB format (leaving the original file untouched). In this way, we can import such data into Metview and have access to all its GRIB/fieldset functionality.
Reading/Writing General ASCII Data to/from Disk
XXXX Supply a text file!
ASCII files that are not in Geopoints, ASCII Table or Lat/Long Matrix format can be read using the read() function. It will return a list of strings - one string will contain the contents of one line of the file. Look at the supplied text file and see that it contains a list of codes for meteorological parameters:
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