How is value of resources measured?

Total economic value (TEV) is a concept in cost–benefit analysis that refers to the value derived by people from a natural resource, a man-made heritage resource or an infrastructure system, compared to not having it. It appears in environmental economics as an aggregation of the (main function based) values provided by a given ecosystem.
The value of an ecosystem can be distinguished as:

Use Value – Can be split into Direct and Indirect use values:

Direct use value: Obtained through a removable product in nature (i.e. timber, fish, water).

Indirect use value: Obtained through a non-removable product in nature (i.e. sunset, waterfall).

Non-use value – Values for existence of the natural resource. For example, knowing that tigers are in the wild, even though you may never see them.

Option value: Placed on the potential future ability to use a resource even though it is not currently used and the likelihood of future use is very low. This reflects the willingness to preserve an option for potential future use.