There are a number of environmental auditing approaches: eco-audits, environmental stocktaking, eco-review, eco-survey, eco-footprinting, and more. State-of-the-environment accounts, environmental quality evaluations and environmental accounts systems collect data on the environment and resources to try and show the state of a land area or sea such as the Baltic or Aegean. Most of these accounting procedures treat the environment as natural capital and try to measure its depletion or enhancement. Techniques such as eco-footprinting seek to trace and value flows of resources and activities associated with discrete areas or activities.