This Link does not exist in your language, View in: English (en),
Or use Google Translate:  
Papia Portugues (mcm) | Change Language (Change Language)

http://edn.link/amazongpsarea

This link takes one to Amazon to view a list of GPS-based area measurement devices.  We have no particular recommendation.  This is a starting point for the concept of area measurement.  Note that there are some that have more capability for international use - units of measure, language, etc.