Portolano

Japanese: Portolano

…Nautical charts developed in Europe in the 13th century with the invention of the compass and advances in navigation technology. A nautical chart from that time, called a Portolano, usually had 32 compass lines radiating from one or two compass roses, as well as the coastline and the names of major coastal places. The coastal topography and islands were depicted accurately for the time, but the positions of each point were relative, and the longitude and latitude were not determined by astronomical observations. …

From the map:

…However, small area maps have no religious connotations, and practicality is fully taken into consideration. Throughout history, nautical charts have been more accurate than land charts, but from around the 13th century, Mediterranean sailors began to use nautical charts called portolanos, which continued into the Age of Discovery. They are characterized by a network of compass lines covering the map, and it is said that the appearance of the compass prompted the creation of these nautical charts. …

*Some of the terminology that mentions "Portolano" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…海図は13世紀に羅針盤の発明と航海技術の進歩に伴ってヨーロッパで発達した。ポルトラノPortolanoという当時の海図には，通常1～2個の方位盤compass roseから放射状に出る32本の方位線と海岸線，主要な沿岸地名が描かれている。沿岸の地形や島なども当時としては正確に描かれているが，各地点の位置は相対的なもので，天文観測により経緯度を決定したものではなかった。…

【地図】より

…しかし小地域図には宗教的色彩はなく，実用性は十分に考慮されている。　歴史時代を通じて海図は陸図に比して精度が高いが，13世紀ころから地中海の船乗りたちの間でポルトラノportolanoと呼ばれる海図が用いられ，大航海時代にも及んだ。方位線網が図面を覆っているのが特色で，羅針盤の登場がこの海図の誕生を促したといわれる。…

※「Portolano」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典第２版について | 情報

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