• Data reference period
• Geographic localization (Portugal)

• ECONOMIC TERRITORY:  Territory that consists on: (a) the geographic territory administered by a government within which persons, goods, services and capital move freely; (b) any free zones, including bonded warehouses and factories under customs control; (c) the national air-space, territorial waters and the continental shelf lying in international waters, over which the country enjoys exclusive rights; (d) territorial enclaves (i.e. geographic territories situated in the rest of the world and used, under international treaties or agreements between States, by general government agencies of the country (embassies, consulates, military bases, scientific bases, etc.); (e) deposits of oil, natural gas, etc., in international waters outside the continental shelf of the country, worked by units resident in the territory as defined in the preceding subparagraphs.
• REFERENCE PERIOD:  Period to which the information refers and which may be a specific day or a time interval (month, fiscal year, calendar year, among others).
• DOMESTIC EXTRACTION:  All solid, liquid and gaseous materials (excluding water and air, but including the water content of materials) that are extracted from economic territory, to be used in production or consumption processes.
• RAW MATERIAL EQUIVALENTS :  Conversion factors used to express a unit of product traded into the amount of material extraction needed, anywhere in the world, to produce the traded product.
• RAW MATERIAL CONSUMPTION :  The amount of material in terms of Raw material equivalents (RME) needed to produce the products consumed in the geographical reference area.
• MATERIAL FOOTPRINT:  See RAW MATERIAL CONSUMPTION

Material footprint = Raw material equivalent of imports (RME_IM) + domestic extraction (DE) - raw material equivalents of exports (RME_EX)