This document provides guidance for survey design, equipment specification, survey methods, sampling and data handling of macroalgae and marine angiosperms such as Zostera in the intertidal soft bottom environment. It does not include polyeuryhaline terrestrial angiosperms that are found in saltmarshes. Ruppia is a genus of angiosperms that can be found in brackish water. This document can also be applied to the study of Ruppia in these environments. The document comprises: development of a mapping and sampling programme; requirements for mapping and sampling equipment; procedures for remote sensing data collection; procedures for direct mapping and sampling in the field; recommendations for taxon identification and biomass determination; data handling.