I’m preparing my new project regarding Japan region. Here is some memo.

Intro

In Japan region, we OpenStreetMapper may trace governmental map.

Especially, GSI map has pretty precise and having good accuracy.

GSI map is based on KibanChizuJoho (Fundamental Geo Data) data which is protected by Japanese Survey law. KibanChizuJoho is an aggregated geo data gathered from municipalities.

Accuracy of KibanChizuJoho is 1:2500 (for urban area) or 1:25000 (for country area). My idea is to cover this 1:25000 area with OpenStreetMap.

List of 1:25000 area

GSI has been publishing those area as following tiled format.

• 縮尺2500分の1相当以上の概ねの範囲

I’ve made a geojson using a script provided by my friend.

Here is a list of municipality which has 1:25000 area. Not perfect through.

• https://github.com/nyampire/jp_25000area

This list indicates 800, out of around 1800, are target.

Challenge

Current available imagery resource is not so clear on country side. (Bing, Mapbox, DG or GSI ortho)

But most of JP municipality is taking aerial imagery by several years period.

Some of those are published under open license. And Mappers are using them as editing resources. (sample: Shiuoka-city on OSM wiki) I would like to encourage to publish the imagery.

Note

• A New Method for the Assessment of Spatial Accuracy and Completeness of OpenStreetMap Building Footprints : Average accuracy is 1:5000 on Lombardy.
• JP mappers already mapped at least 22 area (low population or island) in past Project: My Tasking Manager (This TM is not fully working)