Surface area is a country's total area, including areas under inland bodies of water and some coastal waterways. Development relevance: Total surface area is particularly important for understanding an economy's agricultural capacity and the environmental effects of human activity. Innovations in satellite mapping and computer databases have resulted in more precise measurements of land and water areas. Population, surface area, income, and output are basic measures of the size of an economy. They also provide a broad indication of actual and potential resources. Land area is therefore used as one of the major indicator to normalize other indicators. Limitations and exceptions: The data are collected by the Food and Agriculture Organization (FAO) of the United Nations through annual questionnaires. The FAO tries to impose standard definitions and reporting methods, but complete consistency across countries and over time is not possible. The data collected from official national sources through the questionnaire are supplemented with information from official secondary data sources. The secondary sources cover official country data from websites of national ministries, national publications and related country data reported by various international organizations. Statistical concept and methodology: Total land area includes inland water bodies such as major rivers and lakes. Variations from year to year may be due to updated or revised data rather than to change in area. Including areas of former states; for example, the areas of the Union of Soviet Socialist Republics (USSR) are counted in Russian Federationand other successor states.