Ports list

How were these GPS points obtained?
Year opened data obtained from https://www.singaporepsa.com/about-us/milestones and http://eresources.nlb.gov.sg/infopedia/articles/SIP_577_2005-01-27.html and http://eresources.nlb.gov.sg/infopedia/articles/SIP_2018-04-20_085007.html

Aggregate terminals: https://www.bca.gov.sg/AggregateTerminals/pratandtat.html

LNG Terminal: https://www.ema.gov.sg/cmsmedia/Newsletter/2014/04/spotlight-on/singapores-first-lng-terminal-launched.html