Reduce saturation of pitch outline color

[jeisenbe]

Related to #3651 and #3517

Changes proposed in this pull request:

• Change the pitch outline color to be the pitch color, darkened 20% and desaturated 10%
• Also changes track outline color in the same way. (The track and track outline colors are the same as the pitch and pitch outline colors currently)

Explanation:

• In Add icons for popular sports pitches #3651 and Coordinate shades of non-physical green areas (meta-ticket) #3517, it's been suggested that the pitch outline is not harmonious with the pitch background color.
• The current pitch outline is 30% darker and 20% more saturated than the pitch color (#aae0cb or Lch(85,22,168). This is a much higher chroma than the pitch background color, so the outline does not appear to be based on the same color.
• Examining the outline colors for other features, such as residential, commercial and industrial land, shows than most are 15 darker and just slightly higher chroma (in Lch). So a more appropriate color for pitch and track outlines would be Lch 70,28,168 - 15 points darker than @pitch, and slightly higher chroma: #74b9a0
• Some testing showed that desaturate(darken(@pitch, 20%), 10%) results in an outline color very similar to #74b9a0 - yes, this is still higher chroma than @pitch, even with desaturate 10%.

Test rendering with links to the example places:

https://www.openstreetmap.org/#map=17/40.55731/-122.34847
Before

After (Darken20%, desaturate 10%)

Compare to earlier test with hard-coded #74b9a0 for pitch outline:

Other examples (after PR):
https://www.openstreetmap.org/#map=16/40.5941/-122.3924

https://www.openstreetmap.org/#map=16/40.5902/-122.4029.png

[imagico]

Thanks.

Note the convention is to list Lch color values only if the color was chosen in Lch color space. If like here the color is chosen as an sRGB color this does not make sense.

[jeisenbe]

Sorry, I originally picked the color using LCH, but then went back and found a way to create the same color with `desaturate` and `lighten` but forgot to remove that line

…

On Sun, Feb 3, 2019 at 4:58 AM Christoph Hormann ***@***.***> wrote: Thanks. Note the convention is to list Lch color values only if the color was chosen in Lch color space. If like here the color is chosen as an sRGB color this does not make sense. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#3658 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AoxshAC_WP9LAvL1kJ-i63uoZY7VNAbVks5vJe3VgaJpZM4aUviu> .

[imagico]

That's not what i meant - i meant you added the Lch values in a comment in

openstreetmap-carto/landcover.mss

Line 66 in bf13f67

@pitch: #aae0cb; // Lch(85,22,168) also track

despite the color being not changed and not originally chosen in Lch. No big deal.