Выражение встречается в следующем контексте:

‘fixed measurements’ means measurements taken at fixed
sites either continuously or by random sampling,

Fixed and indicative measurements shall be evenly distributed over the year in order to avoid skewing of results.

Indicative measurement being measurements which are performed at reduced regularity but fulfil the other data quality objectives.

... indicative measurement (like random/passive sampling)…

Заранее спасибо