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[aprssig] LINUX PERL GD images on the fly

Andrew Rich vk4tec at people.net.au
Sun Aug 12 02:14:04 UTC 2007


Those looking for an instant image creation solution for tracking may be
interested in this.

I take data and stream it into mysql. I then use PERL GD to create an image
on the fly.

Here is an example

http://vk4tec.no-ip.org/cgi-bin/adsb_create_image.cgi

And the code

#!/usr/bin/perl -w
use CGI;
use GD;
use DBI;
$x=0;
$y=0;
my $query = new CGI;
my $database_handler =
DBI->connect("DBI:mysql:adsb:host=localhost","root","");
$query1="delete from data where latitude like '%000%'; ";
$statement_handler=$database_handler->prepare ($query1);
$statement_handler->execute;
$query1="select min(latitude) from data ";
$statement_handler=$database_handler->prepare ($query1);
$statement_handler->execute;
$min_lat = $statement_handler -> fetchrow()  ;
$query1="select min(longitude) from data";
$statement_handler=$database_handler->prepare ($query1);
$statement_handler->execute;
$min_lon = $statement_handler -> fetchrow()  ;
$query1="select max(latitude) from data ";
$statement_handler=$database_handler->prepare ($query1);
$statement_handler->execute;
$max_lat = $statement_handler -> fetchrow()  ;
$query1="select max(longitude) from data";
$statement_handler=$database_handler->prepare ($query1);
$statement_handler->execute;
$max_lon = $statement_handler -> fetchrow()  ;
$diff_lat = $max_lat - $min_lat;
$diff_lon = $max_lon - $min_lon;
$lat_scale = 800 / $diff_lat;
$lon_scale = 1200 / $diff_lon;
binmode STDOUT;
print $query->header("image/png");
my $im = new GD::Image(1200,800);
my $white = $im->colorAllocate(255,255,255);
my $black = $im->colorAllocate(0, 0, 0);
my $red = $im->colorAllocate(255, 0, 0);
my $blue = $im->colorAllocate(0, 0, 255);
my $green = $im->colorAllocate(50, 200, 0);
my $purple = $im->colorAllocate(200, 0, 255);
my $orange = $im->colorAllocate(255, 200, 0);
my $grey = $im->colorAllocate(80, 80, 80);
my $light_blue = $im->colorAllocate(0,255,255);
my $yellow = $im->colorAllocate(255,255,128);
$im->filledRectangle(0, 0, 1200, 800, $grey);
$query1="select distinct code from data";
$statement_handler=$database_handler->prepare ($query1);
$statement_handler->execute;
while (($code) = $statement_handler -> fetchrow())
{
$query2="select abs(latitude),abs(longitude),altitude from data where code =
'$code' order by seq desc limit 1";
$statement_handler2=$database_handler->prepare ($query2);
$statement_handler2->execute;
while (($lat,$lon,$alt) = $statement_handler2 -> fetchrow())
{
$x = int(($lon - $min_lon) * $lon_scale);
$y = int(($lat - $min_lat) * $lat_scale);
$im->filledRectangle($x-2, $y-2, $x+2, $y+2, $green);
$im->string(gdSmallFont, $x+23, $y-22, "$code", $light_blue);
$im->line($x+2.5,$y-2.5,$x+15,$y-15, $green);
$im->string(gdSmallFont, $x+23, $y-10, "$alt ft", $yellow);
}
}
$query1="select seq,dtg,code,callsign,altitude,abs(latitude),abs(longitude)
from data order by code";
$statement_handler=$database_handler->prepare ($query1);
$statement_handler->execute;
while (($seq,$dtg,$code,$callsign,$alt,$lat,$lon) = $statement_handler ->
fetchrow())
{
$data_count++;
$x = int(($lon - $min_lon) * $lon_scale);
$y = int(($lat - $min_lat) * $lat_scale);
$im->setPixel($x,$y,$green);
}
$date2=time();
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime($date2);
if ($mday < 10)
{
$day = "0".$mday;
}
else
{
$day = $mday;
}
$month = $mon + 1;
if ($month < 10)
{
$month = "0".$month;
}
if ($hour < 10)
{
$hour = "0".$hour;
}
if ($min < 10)
{
$min = "0".$min;
}
if ($sec < 10)
{
$sec = "0".$sec;
}
$year+=1900;
$date1 = $day."/".$month."/".$year." ".$hour.":".$min.":".$sec;
$im->string(gdLargeFont, 21, 10, "ADS-B Display $date1 - Andrew Rich 2007 -
$data_count points from MySQL table ", $light_blue);
$im->string(gdLargeFont, 21, 25, "$min_lat $max_lat $min_lon $max_lon ",
$light_blue);
print $im->png;
$date2=(time()-(60*10));
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime($date2);
if ($mday < 10)
{
$day = "0".$mday;
}
else
{
$day = $mday;
}
$month = $mon + 1;
if ($month < 10)
{
$month = "0".$month;
}
if ($hour < 10)
{
$hour = "0".$hour;
}
if ($min < 10)
{
$min = "0".$min;
}
if ($sec < 10)
{
$sec = "0".$sec;
}
$year+=1900;
$date1 = $year."-".$month."-".$day." ".$hour.":".$min.":".$sec;
$query="delete from data where dtg < '".$date1."'";
$statement_handler=$database_handler->prepare ($query);
#$statement_handler->execute;




----------------------------------------------------------------------------
Andrew Rich VK4TEC
vk4tec at people.net.au
http://www.tech-software.net



No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.476 / Virus Database: 269.11.13/947 - Release Date: 11/08/2007
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