Doppler image animation with PHP and ImageMagick

Gnome Weather panel provides a radar map using an image URL to show a current weather forecast. Radar map has a support for animated gifs which drove me to develop a little PHP script to make a doppler animation.

I found out that Foreca provides a set of dopper images showing the next 7 hours forecast in Finland. Images have well formed filenames, so there's an easy way to make a script to download them periodically.

Dependencies: ImageMagick and a truetype font

// Nice little script I made courtesy to Gnome Weather Report panel's radar image
chdir(dirname(__FILE__));
exec('rm *.gif');
// download doppler images (foreca provides next 7 hours ahead)
for( $i = 0; $i < 7; $i++ ) {
$hour = date('H')+$i;
$hour = $hour%24;
$hour = str_pad($hour, 2, "0", STR_PAD_LEFT);

$date = date('Ymd').$hour;
$file = 'fin-'.$date.'.gif';

// thanks to taloussanomat :)
$url = 'http://http.foreca.com/xfer/taloussanomat/precipanim/'.$file;
exec( 'wget '.$url );

$date_str = $hour.':00';
// make a date image
exec( 'convert -size 50x20 xc:transparent -font '.dirname(__FILE__).'/tahoma.ttf -fill red '.
'-pointsize 14 -draw "text 5,15 \''.$date_str.'\'" date.png ' );
// add date image on doppler image
exec( 'composite -gravity southeast date.png '.$file.' '.$file );
}

// generate animation (1s delay, infinite loop)
exec( 'convert -delay 100 -loop 0 fin-*.gif doppleranimation.gif' );


The script can be added to crontab, to make the doppler animation refresh once an hour. Working animation can be seen here http://panic.fi/~tero/weather/doppleranimation.gif