---
title: Find a Hidden River
tags:  #openstreetmap  
author: [Taro Matsuzawa aka. btm](https://www.docswell.com/user/smellman)
site: [Docswell](https://www.docswell.com/)
thumbnail: https://bcdn.docswell.com/page/LE1YPXGY7G.jpg?width=480
description: State of the Map 2013 Lightning Talk Original was HTML and markdown, convert to PDF with marp.
published: September 08, 13
canonical: https://www.docswell.com/s/smellman/59N24M-2013-09-xx-state-of-the-map-2013-lightning-talk
---
# Page. 1

![Page Image](https://bcdn.docswell.com/page/LE1YPXGY7G.jpg)

Find a Hidden River
Taro Matsuzawa @smellman
Georepublic Japan


# Page. 2

![Page Image](https://bcdn.docswell.com/page/GEWG2NK1J2.jpg)

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"


# Page. 3

![Page Image](https://bcdn.docswell.com/page/47ZLD3ZXJ3.jpg)

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


# Page. 4

![Page Image](https://bcdn.docswell.com/page/YJ6W1XZPJV.jpg)

Where I live
I live at Sendagaya in Tokyo.


# Page. 5

![Page Image](https://bcdn.docswell.com/page/GJ5M4XWPJ4.jpg)



# Page. 6

![Page Image](https://bcdn.docswell.com/page/LE3WGX46E5.jpg)



# Page. 7

![Page Image](https://bcdn.docswell.com/page/8EDK12QM7G.jpg)

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


# Page. 8

![Page Image](https://bcdn.docswell.com/page/V7PKQ1LQJ8.jpg)



# Page. 9

![Page Image](https://bcdn.docswell.com/page/2JVV5YQPJQ.jpg)



# Page. 10

![Page Image](https://bcdn.docswell.com/page/5EGL69WQJL.jpg)

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


# Page. 11

![Page Image](https://bcdn.docswell.com/page/4JQY4W3W7P.jpg)

nonexistent river
I don't know this river.


# Page. 12

![Page Image](https://bcdn.docswell.com/page/K74WQK11E1.jpg)

If this river exist, like this:


# Page. 13

![Page Image](https://bcdn.docswell.com/page/LJ1YPXG5EG.jpg)

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


# Page. 14

![Page Image](https://bcdn.docswell.com/page/GJWG2NKW72.jpg)

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


# Page. 15

![Page Image](https://bcdn.docswell.com/page/4EZLD3Z273.jpg)

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.


# Page. 16

![Page Image](https://bcdn.docswell.com/page/Y76W1X867V.jpg)

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).


# Page. 17

![Page Image](https://bcdn.docswell.com/page/G75M4X9574.jpg)



# Page. 18

![Page Image](https://bcdn.docswell.com/page/9J29VX2GER.jpg)



# Page. 19

![Page Image](https://bcdn.docswell.com/page/DEY438YGJM.jpg)



# Page. 20

![Page Image](https://bcdn.docswell.com/page/VJNYVQP878.jpg)

Survey
I searched old river using Meiji era maps.


# Page. 21

![Page Image](https://bcdn.docswell.com/page/YE9P6D3XJ3.jpg)

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


# Page. 22

![Page Image](https://bcdn.docswell.com/page/GE8DZ3M9ED.jpg)

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


# Page. 23

![Page Image](https://bcdn.docswell.com/page/LELMDV3M7R.jpg)

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


# Page. 24

![Page Image](https://bcdn.docswell.com/page/4JMYPGD6JW.jpg)

result
Shibuyagawa is a border of Shinjuku-Gyoen.


# Page. 25

![Page Image](https://bcdn.docswell.com/page/PJR91Z4N79.jpg)

I learned
Survey with old map is fun.


# Page. 26

![Page Image](https://bcdn.docswell.com/page/PEXQY928JX.jpg)

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


# Page. 27

![Page Image](https://bcdn.docswell.com/page/3EK93PMLED.jpg)

Thanks for listening!