can you give a bit hint, especially the # at the end, :-)!
  1. my @headers = split ' ', do{ my $raw = <DATA>; $raw =~ tr[",][ ]; $raw }; #"
    • Read the header line into $raw;
    • Get rid of the quotes and commas and replace with spaces;
    • return the modified line to split and split on whitespace;
    • The #" at the end is just a comment; it balances up the earlier ", and prevents it from screwing up the syntax highlighting in my editor.
  2. $line =~ tr[",][ ]; #"

    Same as above. (Though it was wrong for the rest of the lines, a C&P error correct below.)

  3. push @{ $planes{ $aid } }, \%row;

    push a reference to the hash constructed from teh most recent line into the array indexed by the aircraft id.

  4. next unless @{ $planes{ $aid } } > 1;

    If we don't have 2 or more lines (in the array) for this aircraft, we cannot calculate a bearing yet, so skip to the next line.

A couple of corrections and a couple of tweaks:

<Reveal this spoiler or all in this thread>

With the extended dataset (still no course changes!), produces:

C:\test>junk53
Aircraft: 685 heading: -90.000
Aircraft: 721 heading:  0.000
Aircraft: 704 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 709 heading:  0.000
Aircraft: 721 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 709 heading: 90.000
Aircraft: 704 heading:  0.000
Aircraft: 721 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 704 heading:  0.000
Aircraft: 709 heading: 90.000
Aircraft: 721 heading:  0.000
Aircraft: 709 heading:  0.000
Aircraft: 704 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 721 heading:  0.000
Aircraft: 709 heading: 90.000
Aircraft: 704 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 721 heading:  0.000
Aircraft: 709 heading: 90.000
Aircraft: 685 heading: -90.000
Aircraft: 704 heading:  0.000
Aircraft: 721 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 704 heading:  0.000
Aircraft: 709 heading: 90.000
Aircraft: 721 heading:  0.000
Aircraft: 709 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 704 heading:  0.000
Aircraft: 721 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 704 heading:  0.000
Aircraft: 709 heading: 90.000
Aircraft: 721 heading:  0.000
Aircraft: 704 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 709 heading: 90.000
Aircraft: 721 heading:  0.000
Aircraft: 704 heading:  0.000
Aircraft: 685 heading: -90.000
Aircraft: 709 heading:  0.000
Aircraft: 721 heading:  0.000
Aircraft: 709 heading: 90.000
Aircraft: 685 heading: -90.000

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In reply to Re^5: Calculate aircraft headings from GPS data for google kml display by BrowserUk
in thread Calculate aircraft headings from GPS data for google kml display by hujunsimon

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