[OSM-talk] Downloading Version 3 of all bus stops in a country

Safwat Halaby swiftfast at gmx.com
Wed Sep 27 08:46:42 UTC 2017


On Wed, 2017-09-27 at 09:12 +0200, Jo wrote:
> Deleting data on OpenStreetMap and replacing it by imported data is
> obviously never the acceptable approach.
> 
> What I don't understand is why you don't create something that
> compares the
> latest version of all the bus stops in OSM with the latest version of
> the
> GTFS data from upstream.
> 
> Why compare with an inbetween version?

I'm taking a "Newer is better" approach for conflict resolution.

Let's say a user made a 2015 edit for a coordinate (We'll call this
version X). And your 2017 database has a different coordinate (We'll
call this version Y). How do you determine which coordinate to keep?

If you had a 2012 database that would be easy.

Case 1:
2012 database: Y
2015 user edit: X
2017 database: Y

This means the Y has not been updated since 2012. Newer is better, so
trust the user edit and set the coordinates to X.

Case 2:
2012 database: T
2015 user edit: X
2017 database: Y

This means Y is the newest value, and we should override the user edit.

Without two database, we'd have to guess or resort to manual user
intervention via fancy web services.


> What I think is needed is a (web) service that stands between the
> operator
> data, be it GTFS or DB dumps and OpenStreetMap where comparison is
> made and
> which can be used by mappers to either improve OSM, or to send
> feedback to
> the operators that there are issues with the data they provide. Or
> where
> the operators can request flagged stops in bulk.
> 

I am a huge advocate of simplicity. In my humble opinion, web services
and SQL databases are overkill for what I'm trying to do. Your project
spans dozens of files while mine is a single .js file for the JOSM
scripting plugin, which reads two textual stops.txt files from the old
and the newer GTFS databases.



More information about the talk mailing list