The moderators are right. Without any more context it is difficult to see if you are right...I was barely guessing...but I can tell that baselines are reference points for something...what makes no logic without a context is the closing. Are you referring to a transaction?

Foreign Minister Carl Greenidge last Thursday explained to the National Assembly that the Section 9 of the Maritime Act gives him “the power to prescribe by regulations closing lines to delimit our internal waters and it is in this regard that the Maritime zones internal waters and river closing baseline regulations 2015 were enacted on July 23 2015.”
The regulation prescribes the closing lines across the mouths of the three largest navigable rivers of Guyana; the Essequibo, Demerara and Berbice Rivers. The regulation has been already published in the Official Gazette.
“Baselines constitute a fundamental aspect of the regime of zones of jurisdiction established by UNCLOS, since the breadth of the maritime zones under national jurisdiction is to be measured from the baselines. The baseline is also the line which establishes the outer limit of the internal waters in which the State exercises its full sovereignty,” it was noted.
http://www.caribnewsdesk.com/news/10461-venezuela-demands-th...

2.2 Líneas de Base
La extensión de los espacios marítimos previstos en la CONVEMAR, próximos a ser
desarrollados, es definida según criterios de anchura, que tienen como punto de partida
las llamadas Líneas de Base. Es entonces importante, en un primer punto, describir los
diferentes tipos de línea de base previstos en la Convención y, posteriormente, el método de trazado empleado por el Estado ecuatoriano, y por otros países en situaciones
similares. Al respecto, la Convención de las Naciones Unidas sobre el Derecho del Mar diferencia dos tipos de Líneas de Base, en función de las características costeras de cada Estado ribereño
http://repositorio.puce.edu.ec/bitstream/handle/22000/7014/1...

en la determinación de la línea de base y la medición de las zonas marítimas.
https://es.wikipedia.org/wiki/Isla_artificial

A. Determinación de la línea de base
www.uca.edu.ar/uca/common/grupo13/files/A210-04_md.doc