Outline coordination (meta issue)

[polarbearing]

Some areas on the map already use outlines, for other features it has been proposed. This issue intends to coordinate such approaches and find a common language among them, following on #1624 which discusses some candidates.

Current use of outlines

Examples are in z13 and z17.

large parks/reserves

Double line with a darker outside and a more transparent inside. That visualises the direction of the outline even when only parts of the polygon is in the viewer's window.

tourism = theme_park, tourism = zoo, identical, color = #660033 (changed from tourism brown #734a08 in #3582):

• dark line (z>=10): width 1, opacity 0.5, (z>=17): width 2, painted in addition to the light line
• light line (z>=10): width 4, opacity 0.3, (z>=17): width 6
• some fine tuning depending on way size and zoom level new: - old:

nature=reserve

• dark line (z>=10): width 2, opacity 0.15, color green, painted in addition to the light line
• light line (z>=10): width 4, opacity 0.15, color green, (z>=14) width 6

hatched overlays

landuse=military

• line width 3, color military #f55, opacity 0.329, pattern military_red_hatch.png
• Line has no offset so it spills into the neighbourhood and over its fence, see the merge effect with the green.
• Hatching over buildings.

amenity=prison

• line width 3, color #888, opacity 0.329, pattern grey_vertical_hatch.png
• Line has no offset so it spills into the neighbourhood and over its fence.
• Hatching under buildings.

Proposed outlines:

tourism=museum areas #2704 tourism=(accommodation) on the example of leisure=resort #2290
amenity=(uniformed services), i.e. military, police, fire brigade, some drafts in #2670, #3035 boundary=protected area #603 amenity= monastery #3036 leisure=dog_park #3041 boundary=aboriginal_lands #3520

[polarbearing]

I see two separate issues here:

Border of education color is barely visible

This is apparently a side-effect of the recent changes of the education-colour. The border is supposed to make adjacent areas visible, this should be simply fixed b adjusting the border appropriate for the new fill colour. I opened #3519 for this.

I prefer outline more than just a border

This is a more general decision.

[almccon]

I'd like to add boundary=aboriginal_lands to the list of outlines we consider in this issue.

Now that the boundary=aboriginal_lands tag has just been approved, I have a proposed rendering for them in #3520. Basically, I proposed using the same style as national parks, but using a brown color instead of green. However, in order for that to work, we would probably want to change the zoo and theme_park rendering to a different color. Related discussion is #2704 about open-air museum areas.

[kocio-pl]

My proposition is to change zoo and theme_park to violet, which would make possible to merge brown outlines for aboriginal areas without visual clash.

We could also add orange border for museum and other cultural areas, but that is not crucial - it just helps to explain why choose violet for amusement (makes some sense to use less strong color for cultural areas).

[polarbearing]

Added boundary=aboriginal_lands to top post. Maybe we can make a list which outlines should remain in the wider, double-line style (dark 2px + light 6px) (currently theme_park, zoo), and which should use the single (3px) (currently military)

[Adamant36]

@polarbearing, what are the pros and cons of each? Id think as more areas get mapped next to each other where double outline collusion (I think that's the issue with national park boundaries) might happen and more areas get outlines it would be good to have some kind of standardization and move away from the double-line style. I'm sure most people don't know or care what the difference is.

[kocio-pl]

Double line is to make it clear which part is inside and which is outside. It is needed only for big areas which at the same time have no filling, so:

• That's why military areas don't need it - we always see red hatching if we're inside.
• That's also why we could use single line for natural parks on z8-z9 - they have light green filling (but on z10+ they don't have, so we need double lines then).
• It's also not needed for relatively small areas (like zoo) - we can easily check if we're looking inside or outside.

[polarbearing]

thanks kocio-pl, that's the reasoning I remember as well. We already have an adjustment for the width of the double line dependent on zoom level.

I just had the idea we could make it dependent on way area as well. The rule could be that if the object is small enough to fit onto a few tiles in the respective z level, it gets a single line, if it is larger, a double.

[jragusa]

That's would make sense to create a document (or to include into CARTOGRAPHY.md) where all main rules like those indicated by @kocio-pl or those concerning the display of some features (number of occurrences for example) are listed.