Home > Statistics > Japan Statistical Yearbook > Chapter 1 Land and Climate > Explanations
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This chapter covers land and climate.
The section of land contains statistics on the area of the national land as well as those on major islands, lakes, mountains and rivers. Data are obtained mainly from "Abstract of National Land Statistics" by the Ministry of Land, Infrastructure, Transport and Tourism, "Land Survey of Prefectures, Shi, Ku, Machi and Mura" by the Geographical Survey Institute, Ministry of Land, Infrastructure, Transport and Tourism, "Summary Report on Prices, etc. of Fixed Assets (Land)" by the Ministry of Internal Affairs and Communications. As for the area of cultivated land and forest area, see "7 Agriculture, Forestry and Fisheries"; for the area of state-owned land, "5 Public Finance"; for the area of housing land, "18 Housing and Estate"; for the area of parks, "23 Culture"; and for land prices, "17 Prices".
The section of climate contains statistics on main meteorological elements such as temperature, humidity, duration of sunshine, precipitation, etc. Data are obtained from "Annual Report of the Japan Meteorological Agency" and "Climatic Table of Japan" by the Japan Meteorological Agency. For natural disasters, see "26 Environment, Disasters and Accidents".
Areas are obtained from "Land Survey of Prefectures, Shi, Ku, Machi and Mura" which has been compiled annually, as of October 1, since 1955 by the Geographical Survey Institute, Ministry of Land, Infrastructure, Transport and Tourism.
The current areas of shi (cities), ku (wards), machi (towns) and mura (villages) were originally determined using the basic topographic maps (with the scale of 1:25,000) as of October 1, 1988. Since then, the areas have been adjusted annually for the following changes.
For Habomai Islands, Shikotan Island, Kunashiri Island and Etorofu Island, the area was measured on the topographical map (at the scale of 1:50,000) issued on August 1, 1992
Number of islands and length of coastline are based on the survey conducted by the Maritime Safety Agency (now, Japan Coast Guard) in 1986, for the islands with coastline over 0.1 km on the marine charts of the scale of 1:25,000 (for Habomai Islands, Shikotan Island, Kunashiri Island and Etorofu Island, the data are taken from the 1969 survey).
Data are tabulated from the National Land Numerical Information by the Geographical Survey Institute, Ministry of Land, Infrastructure, Transport and Tourism.
The National Land Numerical Information is composed of a variety of digitized geographical information on the state of development and utilization of national land, and is provided for the computer use. A standard areal mesh system is employed for this purpose.
The standard areal mesh system, also called 'grid square system' or 'longitude and latitude system', is a system in which the whole area of the country is divided into areal meshes of equal size with the aid of the specified longitude and latitude lines. The standard areal meshes consist of the primary areal division, the secondary areal division and the tertiary areal division and are given appropriate code numbers which are based on longitude and latitude and constitute locational information in the National Land Numerical Information. In general, this tertiary division (a square with about 1 kilometre on a side) is called a basic areal mesh. For details, see "Guide to the Application of National Land Numerical Information" by the Geographical Survey Institute, Ministry of Land, Infrastructure, Transport and Tourism and "A Guide to the Grid Square Statistics" by the Statistics Bureau, Ministry of Internal Affairs and Communications.
The configuration of each basic areal mesh is represented by the configuration of the largest area in the section.
Gradients are calculated from the altitude of central points of 250 metre meshes. The maximum and minimum gradients are obtained from the gradients between the reference point and neighbouring points in eight directions. The gradient shown in this Yearbook represents the maximum gradient.
Data are derived from "Summary Report on Prices, etc. of Fixed Assets (Land)" compiled by the Ministry of Internal Affairs and Communications based on the reports from the prefectural offices on fixed assets as of January 1 of each year.
Private land refers to taxable land (paddy fields, farm fields, forests, residential lands, pastures, grasslands, spas, ponds and marshes, and miscellaneous land) registered in the basic ledgers (i.e., the land ledgers and the supplemental land ledgers) , which are kept in shi (cities), machi (towns) and mura (villages) for the purpose of imposition of the fixed asset taxes. Accordingly, private lands under the statutory tax exemption are included, but excluded are following lands, which are exempted from the fixed asset tax, such as lands owned by the government or the local public bodies, lands for official or public use, graveyards, roads, irrigation channels, sewerage, reservoirs, reserved forests, private school sites, compounds of religious bodies, etc.
Data are obtained from "Annual Report of the Japan Meteorological Agency" compiled by the Japan Meteorological Agency from the surface observations at observation stations throughout the country during the year.
Observations of air temperature, relative humidity, etc. are made at the scheduled times of a day, but the frequency of observation varies depending on the observation station and the object. The average of a day is the average of all observations during the day; average of a month is the averages of days in the month; and average of a year is the averages of months in the year. Arithmetic average is used for the calculation. Normal values are taken from "Climatic Table of Japan" published decennially by the Japan Meteorological Agency. The normal annual values are calculated according to the widely used international practice by taking average of 30 years consisting of three decades on the Gregorian calendar. The average normal values now in use are the average of the 30-year period from 1971 to 2000.
Meteorological statistics were not compiled when the observations were not considered comparable or the number of observations is not enough. In January 2005, however, the method was improved to compile statistics as far as possible by making maximum use of the observations. Annual data of the past are compiled again by the new method.
Data are based on the sun-tracking sunshine recorder or electric pyrheliometer, indicating total hours of sunshine on the ground.
Data refer to the maximum value of daily precipitation.
Data are measured by an anemograph with recording wind vane of pinwheel type. Maximum wind speed relates to the average of ten minutes.
Data refer to the maximum depth of snow during the cold season (from autumn of the preceding year to spring of the year stated).
"Clear day" is defined as the average cloud cover is less than 1.5. The cloud cover is expressed by the proportion of cloudy space in the sky, with 10 as the total. "No-sunshine day" is a day with less than 0.1 hour of sunshine. "Rainy day" is a day with 1 millimetre or more of precipitation, and "snowy day" is a day with any snowfall (excluding snow hail, ice hail, sleet and hailstones) irrespective of quantity.
