Rendering of hedge as areas, or not.

[SomeoneElseOSM]

This style currently treats hedges as areas and this causes issues when linear hedges are combined in OSM with area features such as "landuse" - the result is a hedge area, which is probably not was intended. What follows is mostly an extract from an email to the person who reported this issue.

An example is here: https://www.openstreetmap.org/way/106629251 in OSM Carto, which looks like this: https://map.atownsend.org.uk/maps/map/map.html#17/51.66781/-0.59354 in this style.

I think that the history of this issue is more or less as follows:

• before 2019, the hedge rendering at OSM Carto, and and map.atownsend.org.uk (which was based on OSM Carto from 2014) has hedges as an area tag, so that hedges could be drawn as areas.

• A number of mappers combined hedge tags with landuse tags resulting in the effect that you describe

• In 2019, the pull request at https://github.com/gravitystorm/openstreetmap-carto/pull/3844 was accepted into OSM Carto, resulting in (a) hedges no longer being an considered an area tag by default and (b) there being no way to make a hedge an area, not even with "area=yes".

• Numerous people complained about the new rendering - see e.g. https://github.com/gravitystorm/openstreetmap-carto/issues/4200 , https://github.com/gravitystorm/openstreetmap-carto/issues/4111 , https://github.com/gravitystorm/openstreetmap-carto/issues/4374 . See also https://github.com/gravitystorm/openstreetmap-carto/pull/3834 .

• Someone's now pointed out the resulting problem with this style using an example similar to but different from the "Amersham School" one above.

I think that it's beneficial to be able to show hedge areas where they've been mapped as such. when I looked (in 2019) there was enough use of hedge areas to make that feature worth keeping. This is why I didn't follow OSM Carto down the path of "assume hedges are linear features only". The only options are:

1. Treat all hedges as linear in the style
2. Manually change all hedge areas to some other area tag (perhaps "shrubbery") feature in the OSM data
3. If a hedge is combined with another area feature, pretend the hedge doesn't exist, and let the "other area feature" provide the fill.
4. If a hedge is combined with another area feature, assume that the hedge is actually linear, and let the "other area feature" provide the fill.

Of these, I've rejected (1) for the reasons already described above. I'm not a fan of (2) - manually editing OSM data to be "something that it is not for the benefit of a lesser used map style" sounds like a bad idea to me. (3) should be doable without too much work, since I don't think that hedge features should coexist with many others . (4) is like (3) but with the extra requirement to define a "linear only" hedge feature in the style, duplicating how line "barrier=hedge" are shown, but not how polygon "barrier=hedge" are.

[SomeoneElseOSM]

Fixed by https://github.com/SomeoneElseOSM/SomeoneElse-style/commit/4f2c6f269ad9d491b27f7d79c23c7f1b1ca66303 and https://github.com/SomeoneElseOSM/openstreetmap-carto-AJT/commit/06bff9da232293845c7251e16e8ded78bcf931ea

[SomeoneElseOSM]

Now live - see here, which corresponds to this in OSM.