Allow snap-to tracing from another layer

[csytsma]

First of all, thank you to all the people that have built and maintain JOSM. It is a super useful tool.

I would love the ability to be able to trace a line from another layer when drawing lines, and have it 'snap' or automatically trace along. For example, if I have my own GPX or OSM layer with lines on it. Then while having my Data Layer active, be able to start drawing a line on top of one of the lines in the GPX layer, and as I moved my mouse, it either automatically drew the line on top of the lower line towards my mouse, or if I clicked, it would draw the line up to the point along the line.

This would be useful so I wouldn't have to try to precisely draw on top of the line, I could just be close, and it would auto draw precisely on top of the lower layer line. It would probably also prevent people from mass uploading GPX tracks, because it would be really quick to re-draw the GPX route.

I hope this is clear. I didn't see a plugin that already did this, so I apologize if I'm asking for something that's already available.

Thanks,
Cory

[bastiK]

Judging from my own experience, GPS can be offset quite a bit, for example in the forest or cities. It is a better strategy to also take aerial imagery and memory into account (if present). So snapping to the GPX would not necessarily improve the quality of the traced ways.

[skyper]

Replying to bastiK:

Judging from my own experience, GPS can be offset quite a bit, for example in the forest or cities. It is a better strategy to also take aerial imagery and memory into account (if present). So snapping to the GPX would not necessarily improve the quality of the traced ways.

+1

If you really want the shape of the GPS you can already convert gpx -> data and copy objects from layer to layer or merge layers.

[Don-vip]

Agreed, it would no produce good quality data for most of our users.