Re^6: Calculate aircraft headings from GPS data for google kml display

Thank you for the excellent explanation, it all becomes quite clear !

I have made few tweak on your code and try to integrate my original code, which is to generate kml file for google display, here is my attempt, but unfortunately the code doesn't run as expected. I think the problem is at reading the file. i switch from using 'while' to 'foreach' to loop through the file, but it doesn't work. I must have done something silly. Any suggestions ?!

Also i have also replaced your 'next unless' statement to 'if', it should works the same.

#!/usr/bin/perl
use strict;
use POSIX qw(ceil floor);

open(INPUT, $infile);
my @lines = <INPUT>;
close(INPUT);

open(OUTPUT, ">$outfile");

my $timeCounter = 0;
my $seconds = 0;
my $minutes = 0;
my $hours = 0;
my $comma = ",";
my $space = " ";

print OUTPUT "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"."\n";
print OUTPUT "<kml xmlns=\"http://earth.google.com/kml/2.1\">"."\n";
print OUTPUT "<Folder>"."\n";
print OUTPUT "<LookAt><longitude>-0.45</longitude><latitude>51.4666667
+</latitude><altitude>1500</altitude><range>7000</range><tilt>65</tilt
+><heading>0</heading></LookAt>"."\n";


my @headers = split ' ', do{ my $raw = <INPUT>; $raw =~ tr[",][ ]; $ra
+w }; #"
printf @headers;
my %planes;

foreach my $currentLine(@lines)
{
    
    my @fields = split',', $currentLine;

    #--- At this point, we have the data from the current line. We nee
+d to convert this to appropriate kml elements
    
    
    my %row; @row{ @headers } = @fields;
    
    
    #--- Get all the elements
    my $rowid              = $row{rowid};
    my $aid             = $row{aircraft_id};    
    my $actual_date_time   = $row{actual_date_time};
    my $latitude           = $row{latitude};
    my $longitude          = $row{longitude}; 
    my $radio_altitude     = $row{radio_altitude};
    my $ground_speed       = $row{ground_speed};
    my $thrust_engine_1    = $row{thrust_engine_1};
    my $thrust_engine_2    = $row{thrust_engine_2};
    my $nox_total          = $row{nox_total};
    my $co_total           = $row{co_total};
    
    
    #--- Now, convert start and end times into UTC
    my @timeString = split(my $space,$actual_date_time);
    $actual_date_time = @timeString[0]."T".@timeString[1];

    #--- Determine the heading
    push @{ $planes{ $aid } }, \%row;
    
    if ( @{ $planes{ $aid} } > 1)
    {

    my $lat1 = $planes{ $aid }[ -2 ]{latitude};
    my $lat2 = $planes{ $aid }[ -1 ]{latitude};
    my $dlat = $lat2 - $lat1;

    my $lon1 = $planes{ $aid }[ -2 ]{longitude};
    my $lon2 = $planes{ $aid }[ -1 ]{longitude};
    my $dlon = $lon2 - $lon1;
    
    my $y = sin( $dlon / 180 ) * cos( $lat2 /180 );
    my $x = cos( $lat1 /180 ) * sin( $lat2/180 ) - sin( $lat1/180 ) * 
+cos( $lat2/180 ) * cos( $dlon/180 );
    my $heading = atan2( $y, $x ) * 57.2957795;
    }
    else 
    {
    my $heading= 0;
    }

    #--- (1) Determine the geometry
    my $icon = "./blue_plane.png";
    print OUTPUT "<Placemark><Style><IconStyle><scale>1.0</scale><head
+ing>";
    print OUTPUT my $heading;
    print OUTPUT "</heading><Icon><href>$icon</href></Icon></IconStyle
+></Style><Point><coordinates>";
    print OUTPUT $longitude.$comma.$latitude.$comma.$radio_altitude;
    print OUTPUT "</coordinates><altitudeMode>relativeToGround</altitu
+deMode></Point>";
    print OUTPUT "<TimeStamp><when>$actual_date_time</when></TimeStamp
+>";
    print OUTPUT "<description>"."ID:".$rowid."<hr/>"."time:".$actual_
+date_time."<hr/>"."Ground_speed:".$ground_speed."<hr/>"."Thrust_engin
+e_1:".$thrust_engine_1."<hr/>"."thrust_engine_2:".$thrust_engine_2."<
+hr/>"."nox_total:".$nox_total."<hr/>"."co_total:".$co_total."<hr/>"."
+longitude:".$longitude."<hr/>"."latitude:".$latitude."<hr/>"."radio_a
+ltitude:".$radio_altitude."<hr/></description>";
    print OUTPUT "</Placemark>"."\n";
    }


print OUTPUT "</Folder></kml>";
[download]

Thanks in Millions !

Comment on Re^6: Calculate aircraft headings from GPS data for google kml display Download Code

Replies are listed 'Best First'.
Re^7: Calculate aircraft headings from GPS data for google kml display by BrowserUk (Patriarch) on Jun 11, 2014 at 02:10 UTC
You're slurping the entire file into an array: `open(INPUT, $infile); my @lines = <INPUT>; close(INPUT);` [download] Which means by the time you reach where I loaded the header line: `my @headers = split ' ', do{ my $raw = <INPUT>; $raw =~ tr[",][ ]; $ra +w }; #"` [download] There is nothing left to read. Either shift the first line off of the array: `my @headers = split ' ', do{ my $raw = shift @lines; $raw =~ tr[",][ ] +; $raw }; #"` [download] Or don't slurp the file and revert to using while. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l] [select]
Re^8: Calculate aircraft headings from GPS data for google kml display by hujunsimon (Sexton) on Jun 26, 2014 at 15:01 UTC
Hi BrowserUk, sorry, went away for holiday last week. thanks a lot for your advice, it works like a charm now ! Simon	[reply]


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