Add dedicated icon for memorial benches

[Tomasz-W]

Continuation of unfinished #3356.

As memorial benches has partly simple amenity character and partly memorial character, both bench and memorial icon don't show their character properly.

Proposal is to render combination of amenity=bench + historic=memorial by dedicated icon in amenity-brown:

Gist link: https://gist.github.com/Tomasz-W/9ad756936dab43da9383c6586551e2e0

This change was actually approved in #3088 but there was some technical dificulties in a bigger PR back then, so I'm opening this ticket to not forgot about this remaining part.

@jragusa I'm mentioning you as you were an author of original memorial subtags PR.

[jragusa]

I tried again to resolve this problem but it does not work :/ With the code below, it leaves the generic memorial icon

  [feature = 'historic_memorial'][zoom >= 17] {
    [feature = 'amenity_bench'] {
      marker-file: url('symbols/historic/memorial_bench.svg');
      marker-fill: @memorials;
      marker-placement: interior;
      marker-clip: false;
    }
  }

I have also tried adding bench in dedicated amenity_ section in project.mml and add condition as following:

  CASE 
    WHEN historic IN ('memorial')
      AND amenity IN ('bench')
      THEN 'yes' ELSE 'no' 
  END AS memorial_bench,

  [feature = 'historic_memorial'][zoom >= 17] {
    [memorial_bench = 'yes'] {
      marker-file: url('symbols/historic/memorial_bench.svg');
      marker-fill: @memorials;
      marker-placement: interior;
      marker-clip: false;
    }
  }

But it displays the generic bench icon.

The best answer would be to have historic = memorial + memorial = bench

[polarbearing]

please fix typo in title

[Adamant36]

@jragusa, do we know what the number of memorial benches tagged are out there? TagInfo says there's 59 uses of memorial=bench. I couldn't find any information on the combination of historic=memorial + amenity=bench though. But memorial benches aren't listed on either of their wiki pages.

It might worth asking in the tagging mailing list, or the memorial discussion page, and closing this issue until its actually decided whats best to use.

[jeisenbe]

The combination amenity=bench + historic=memorial is only used 220 times. This does not require a unique icon at this time. I'm closing this issue for now.