Copying exact positions from background layer

[jidanni]

I hear the British now have a perfectly aligned cadastral background layer.

This brings up a question. With perfectly aligned layers. If one wants to copy lines, or corners (points), currently one is still using (one's finger or) one's mouse, to put the approximate position on the map, governed by the user's visual and wrist alignment.

It would be better to have some kind of direct system so when the user chooses an item the exact same position could be planted on the map without even (on the ground) millimeters of difference.

It could be argued that the map is merely a painting. A sort of watercolor, representing reality.

But it doesn't have to be that bad. Some parts of it could be exactly the same as the original data. For instance international boundaries.

Yes you could say, "Well they are all batch-imported anyway, so don't worry about the big stuff."

But that is not always the case.

Anyway for the little stuff, like boundaries of parks. It still would be too bad to have inconsistencies embedded in the map when it doesn't have to be that way.

Also this might all depend on some kind of future vector background layer implementation. But I don't know all about that... That is some other question.

[1ec5]

iD supports displaying vector data in a separate layer that you can interact with. In the Map Data panel, click the “…” button next to the Custom Map Data checkbox. Upload a GPX, KML, GeoJSON, or MVT (Mapbox Vector Tiles) file, or enter a URL template for a hosted file in one of these formats. This diary entry explains how to create an MVT layer and expose it to iD.

Most online GIS layers are available through either a MapServer or a FeatureServer endpoint. If it’s a MapServer, you can add it as a raster layer but that’s it; you’d need to contact the layer’s maintainer for more options. #8327 tracks supporting a FeatureServer endpoint. In the meantime, some FeatureServers do have the Query method enabled, which can give you a URL endpoint for the query results as GeoJSON, compatible with the feature above.

The most you can do with a custom data layer is inspect each individual feature interactively. There isn’t an option to copy the feature to the main OSM layer. That was the idea in #4164, but it was controversial, as you can read about in that issue. The idea eventually grew into a fork called Rapid, although there remains no option for bringing in features from an arbitrary FeatureServer.

[jidanni]

Okay, that is all so mind-boggling that I'm not exactly sure if my issue here has any fresh ideas or not. So I'm not sure if I should close it.