Land area is a country's total area, excluding area under inland water bodies, national claims to continental shelf, and exclusive economic zones. In most cases the definition of inland water bodies includes major rivers and lakes. Development relevance: Land 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, land 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 does not include 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.