For install Weathermap you need have Cacti with Plugin Architecture
For PHP we need GD library
apt-get install php5-gd
Go to Cacti Plugins
cd cacti/plugins
wget http://network-weathermap.com/files/php-weathermap-0.97c.zip
unzip php-weathermap-0.97c.zip
Change owner
chown -R www-data:www-data *
cd weathermap
set
$ENABLED=true;
in file editor.php
Tnen enable Weathermap in Cacti web