HUGE differences between reports on piwik and Google analytics

Hi there, This is my first message here,

Some days ago, since know about piwik and the goods comments in a forum, I decided install it on my server. All run well, (run in hostgator). The only issue I solved with the customer support (withe list the domain where piwik is installed), and really was with the pluging with wordpress WP-Piwinc, instead piwik directly.

Now, I'm running the twoo statistics system (piwik and analytics) some days, but I fond a HUGE differences between both system in visits.numbers. piwik, double the numbers of visits (today report).

Here some screenshots

Analytics



Piwik



I understand that the two systemns works different, but I'm surprised for the great differences between one and other one.

Greetings
Valentín.