TOKYO METROPOLITAN GOVERNMENT BUREAU OF GENERAL AFFAIRS Open in Separate Window

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Open in Separate WindowThe official website of the Tokyo Metropolitan Government

国境離島スライドパズルを完成させよう！

The Geospatial Information Authority of Japan established electronic reference points on Minamitorishima Island (at the southernmost edge of Japan) in December 2002 and on Okinotorishima Island (at the easternmost edge of Japan) in June 2005. These electronic reference points can also be used as a basis to understand the motion of plates in the Pacific Ocean and to conduct various surveys and observations.

CLOSE
Click here for
the Geospatial Information Authority of
Japan's map

Let's get a feel for the distance between
he southernmost and easternmost edges of Japan!

< How to Use on a PC >

Let's start by clicking on Tools!When you click on Tools, each tool appears on the right side of the screen! Let's click on Measure from there!
虫眼鏡

If you zoom in on the map, you can see that Okinotorishima Island is shaped like an eggplant and Minamitorishima Island is shaped somewhat like a triangle!

虫眼鏡

How many kilometers is your home from Okinotorishima and Minamitorishima Islands?
How many laps would it be on the Yamanote Line? Let's find out!
*Let's try dividing: one complete loop on the Yamanote Line is about 34.5 km!

Click the starting point you want to measure, double-click at the end point, and the distance will appear in the upper right hand corner!

< How to Use on a Smartphone >

  • Let's start by clicking the three lines in the upper right hand corner of the screen!
  • Click on the Tools icon that appears below!
  • When you click on Tools, each tool appears on the right side of the screen! Let's click on Measure from there!
  • Click the starting point you want to measure, double-click at the end point, and the distance will appear in the upper right hand corner!
  • Click here for Okinotorishima Island's electronic reference point!
  • Click here for Minamitorishima Island's electronic reference point!

Electronic reference points and special electronic reference points throughout Japan

There are approximately 1,300 electronic reference points nationwide at approximately 20 km intervals.
The data received is collected and analyzed by the Geospatial Information Authority of Japan (Tsukuba City, Ibaraki Prefecture).
They can also capture crustal movement.

Electronic reference points and special electronic reference points throughout Japan

Chart Source: Triangulation Stations and Electronic Reference Points (Geospatial Information Authority of Japan website)
https://www.gsi.go.jp/KIDS/KIDS09.html

What is an electronic reference point? (Geospatial Information Authority of Japan website)
https://www.gsi.go.jp/denshi/denshi_about_GEONET-CORS.html