id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
24805	Weight value lost when modifying ways — automatic recalculation needed	marius.karch@…	marius.karch@…	"**Summary**
When a way is modified in JOSM (e.g. moved, extended, or split), custom length-based tags are either silently retained with their outdated value, or dropped entirely. We are looking for a way to automate recalculation of such tags after geometry changes.


**Background**
We use JOSM as the primary editing tool for a custom indoor/campus routing graph. Each way carries a weight tag encoding its traversal cost (physical length in meters), which is consumed by a shortest-path routing algorithm.

The problem: whenever a way's geometry is changed, the weight tag either keeps its previous (now incorrect) value, or disappears completely — with no indication of either in the editor. Both cases result in corrupt routing data. Over time, as more edits are made, an increasing number of ways carry stale or missing weight values, silently degrading routing quality in the downstream application.

Manual correction is not a sustainable option, as the effort scales with every edit made to the dataset.


**Request**
Is there an existing mechanism in JOSM to automatically recalculate a tag value (such as way length) after a geometry edit? If not, would the JOSM team be open to supporting this use case — either as a core feature, a validator rule, or by other means?

We are happy to provide sample data or further detail if useful."	enhancement	needinfo	normal		Core	latest