Differentiate woodland polygon rendering by leaf_cycle

[BushmanK]

Once rendering style for natural=wood has changed recently, it seems like it's time to think about recently introduced, but quite popular tags such as leaf_cycle and leaf_type (more that 1 million entries in the whole world).

I made several sample patterns using current pattern used for natural=wood.

leaf_type=needleleaved no leaf_cycle

leaf_type=broadleaved no leaf_cycle

leaf_type=broadleaved leaf_cycle=deciduous

For leaf_cycle=evergreen, leaf_cycle=semi_evergreen, leaf_cycle=semi_deciduous I suggest using pattern with fully filled tree outlines, but any other ideas are welcome, for sure.

So, basically, for unknown life cycle outline should be empty; for trees, looking differently through the year - half-filled, for trees, not changing or barely changing its appearance - fully filled.

While not all needle-leaved plants have similar conic shape as fir or cypress (mature pine, for example), in majority of cases, this shape is associated with them pretty well. So, I believe, using conic and rounded canopy outline is legitimate way to show broadleaved and needleleaved trees.

Actually, I have no idea how to show leafless plants - hard to imagine unified symbol for them, they are too different.

[matkoniecz]

leaf_type is covered by #822

[BushmanK]

I see.
It seems like my idea of empty, half-filled and filled outlines is new.

[pnorman]

Closing in favour of #822, as there is substantial overlap.

[kocio-pl]

@BushmanK Nice new idea, please tell about it on #822.

[kocio-pl]

Reopening, because leaf_cycle=* is still not implemented.

Simple try with filling half (semi_/deciduous) or full (semi_/evergreen) areas:

Broadleaved:

Needleleaved:

Mixed leaf types:

Unknown leaf types:

[pnorman]

I think this is trying to cram too much non-obvious detail into the symbology

[matthijsmelissen]

+1

[kocio-pl]

Do you think this is just suboptimal solution or leaf_cycle is too much to fit in general style and we should close the issue as wontfix?

[matkoniecz]

Yeah, seconds after reading description at #1756 (comment) I am forgetting meaning of symbols.

I see no reasonable way to show that.

[imagico]

Keep in mind that rendering leaf_type but not leaf_cycle would bring in a significant amount of additional geographical bias - the almost completely binary distinction of deciduous broadleaved and evergreen needleleaved is something relatively specific to the northern hemisphere temperate zone you all live in. In other parts of earth leaf_cycle is often a much more significant distinction than leaf_type.

[kocio-pl]

Yeah, seconds after reading description at #1756 (comment) I am forgetting meaning of symbols.

For me it's easy:

• full filling - leaves always present
• partial filling - leaves not always present
• no filling - unknown leaf cycle (as currently rendered, so I didn't repeat it)

It just makes a 9 combinations matrix with leaf types, so it looks like a lot of symbols, but it's just 3x3 (plus leafless as a special case).

[pnorman]

Do you think this is just suboptimal solution or leaf_cycle is too much to fit in general style and we should close the issue as wontfix?

wontfix, I just don't see it as possible.

It just makes a 9 combinations matrix with leaf types, so it looks like a lot of symbols, but it's just 3x3 (plus leafless as a special case).

It's better than 9 distinct symbols, but it's still too much. I have other concerns with the details of symbols, but the main one is that it's too much for a general style.

[kocio-pl]

I guess we should close it now for practical reasons (I see open tickets as worth fixing and this one doesn't look that way). If a more acceptable solutions will ever show up, it can be reopened of course.

[imagico]

Reopening this as far as leaf_cycle is concerned because:

• it was closed for unclear reason (not worth fixing or not feasible fixing).
• plenty of options to illustrate leaf_cycle in a pattern are known and some have been demonstrated on digital maps - see for example here.
• as pointed out above in Differentiate woodland polygon rendering by leaf_cycle #1756 (comment) preferentially distinguishing leaf_type rather than leaf_cycle is communicating a significant geographic bias because both the correlation between leaf_type and leaf_cycle and the higher significance of leaf_type in practical differentiation of woodlands is quite specific to the northern hemisphere temperate zone.
• use of leaf_cycle on woodland polygons has grown a lot since this was closed, it numbers nearly 1 million now - which is more than leaf_type back in 2017. Also percentage of woodland polygons tagged with leaf_cycle has increased quite a lot:

tag	2018	with leaf_cycle	percent	2022	with leaf_cycle	percent
natural=wood	4.6M	111k	2.4	8.5M	634k	7.5
landuse=forest	3.5M	115k	3.3	5.0M	333k	6.7