This polygon shapefile is an index to the map series, '極東「ソ」領飛行場一覧圖 (ザバイカル) | 五十万分一後貝加爾方面素圖 -- Kyokutō "So" ryō hikōjō ichiran zu (Zabaikaru) | 1:500,000 Gobaikaru hōmen sozu.' This map series was originally produced by the Japanese Land Survey Department of the General Staff Headquarters [1941, 1947]. Stanford University Libraries holds a large collection of Japanese military and imperial maps, referred to as gaihōzu, or
'maps of outer lands.' These maps were produced starting in the early Meiji (1868-1912) era and the end of World War II by the Land Survey Department of the General Staff Headquarters, the former Japanese Army. The Library is in the process of scanning and making available all of the maps in the collection. This layer provides an index map that can be used to locate individual scanned map sheets. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.