ISO/IEC 18025:2014 provides mechanisms to specify unambiguously objects used to model environmental concepts. To accomplish this, a collection of nine EDCS dictionaries of environmental concepts are specified:
classifications: specify the type of environmental objects;
attributes: specify the state of environmental objects;
attribute value characteristics: specify information concerning the values of attributes;
attribute enumerants: specify the allowable values for the state of an enumerated attribute;
units: specify quantitative measures of the state of some environmental objects;
unit scales: allow a wide range of numerical values to be stated;
unit equivalence classes: specify sets of units that are mutually comparable;
organizational schemas: useful for locating classifications and attributes sharing a common context; and
groups: into which concepts sharing a common context are collected.
A functional interface is also specified.
As denoting and encoding a concept requires a standard way of identifying the concept, ISO/IEC 18025:2014 specifies labels and codes in the dictionaries.
ISO/IEC 18025:2014 specifies environmental phenomena in categories that include, but are not limited to, the following:
abstract concepts (e.g., absolute latitude accuracy, geodetic azimuth);
airborne particulates and aerosols (e.g., cloud, dust, fog, snow);
animals (e.g., civilian, fish, human, whale pod);
atmosphere and atmospheric conditions (e.g., air temperature, humidity, rain rate, sensible and latent heat, wind speed and direction);
bathymetric physiography (e.g., bar, channel, continental shelf, guyot, reef, seamount, waterbody floor region);
electromagnetic and acoustic phenomena (e.g., acoustic noise, frequency, polarization, sound speed profile, surface reflectivity);
equipment (e.g., aircraft, spacecraft, tent, train, vessel);
extraterrestrial phenomena (e.g., asteroid, comet, planet);
hydrology (e.g., lake, rapids, river, swamp);
ice (e.g., iceberg, ice field, ice peak, ice shelf, glacier);
man-made structures and their interiors (e.g., bridge, building, hallway, road, room, tower);
ocean and littoral surface phenomena (e.g., beach profile, current, surf, tide, wave);
ocean floor (e.g., coral, rock, sand);
oceanographic conditions (e.g., luminescence, salinity, specific gravity, turbidity, water current speed);
physiography (e.g., cliff, gorge, island, mountain, reef, strait, valley region);
space (e.g., charged particle species, ionospheric scintillation, magnetic field, particle density, solar flares);
surface materials (e.g., concrete, metal, paint, soil); and
vegetation (e.g., crop land, forest, grass land, kelp bed, tree).
