Find a Hidden River

Find a Hidden River Taro Matsuzawa @smellman Georepublic Japan

about me 1. Programmer at Georepublic Japan 2. Member of Mozilla Community in Japan. Author of two japanese books about Firefox (Firefox 3 Hacks, Firefox Hacks Rebooted) 3. Speaker of FOSS4G, title is "SVGMap - Tilemap without Javascript"

my company Georepublic supports OpenStreetMap because CEO, CIO and others(include me) are Mapper. Hal Seki - CEO Daniel Kastl - CIO

Where I live I live at Sendagaya in Tokyo.

The town is near Shinjuku Gyoen. It's a beatiful park.

wrong data When I surveyed at Shinjuku Gyoen, I found wrong data.

nonexistent river I don't know this river.

If this river exist, like this:

What is this data? The river name is "渋谷川暗渠"(Shibuyagawa-Ankyo). Shibuyagawa is mean "Shibuya river", what is "Ankyo"?

Ankyo Ankyo is "blind ditch" or "underground drain". I don't know about Ankyo until searching in Google:-(

in Google I found that: Too many parts of Shibuya river are covered with concrete by redevelopment at Tokyo Olympics in 1964. We need to research using a map before 1960s.

Old map I use "今昔散歩"(Konjaku-sampo) application. It is a smartphone application for iOS or Android. It can show three maps(Edo era (1603-1867) map, Meiji era (1868-1912) map, and OS's map).

Survey I searched old river using Meiji era maps.

I started at Meiji park and walk with looking that application.

Found a remains I found a Ankyo's remains near police station.

complete survey I walk along this river, up north and I found end of shibuyagawa.

result Shibuyagawa is a border of Shinjuku-Gyoen.

I learned Survey with old map is fun.

Next End of shibuyagawa equals Start of 玉川上水(Tamagawa Jousui).

Thanks for listening!