Question about symbology and expressions

[sylvain258]

Hi,

I am working on datae and I am trying to create a symbology using expressions. Problem is at 'circle-color', I have indicated that white is a default color, but in my app, the rendering is black.

I don't understand why, this is my code.

Thank you very much for your help,

Sylvain

const date0 = ["<=", ['get', 'annee'], 1904];
const date1 = ['all', ['>', ['get', 'annee'], 1904], ['<=', ['get', 'annee'], 1945]];
const date2 = ['all', ['>', ['get', 'annee'], 1945], ['<=', ['get', 'annee'], 1975]];
const date3 = [">=", ['get', 'annee'], 1975];
const daten = ["==", ['get', 'annee'], null]; // possible that the problem is here (with coalesce ?)

 `     map.addLayer({
        'id': 'CPAAPI',
        "type": 'circle',
        'source': 'cpa',
        'source-layer': 'cpa_carte',
        'layout': {},
        'maxzoom': 24,
        'minzoom': 1,
        "paint":{
          "circle-radius": [
            'interpolate',
            ['linear'],
            ['zoom'],
            5,1,
            7, 3,
            14, 5
          ],
          'circle-color': [
            'case',
            date0,
            "#cdcdcd", 
            date1,
            '#C58300', // marron
            date2,
            '#C500B6', // violet
            date3,
            '#B0C500',
            daten,
            '#e31a1c',
            '#fff' // app returns black
          ],
          "circle-stroke-width": 1,
          "circle-stroke-color": "#00353D"
        }
      });`

[HarelM]

I would try different stuff and see what works. I don't know of a better way...

[sylvain258]

There is no documentation on expressions except any examples on MapLibre website.

What would be these different stuffs ?

Thanks

[HarelM]

Try modifying the expression until you get something basic working and then modify again.
You can also check the tests in the style-spec repo to see more options, but I'm not sure how helpful are those.
Generally speaking, this is a hard thing to document as there are a lot of options...

[sylvain258]

Answer about this question :

I generated symbology with MapBox Studio, in order to have exact syntax.

There may be a bug here.

'circle-color': [ "case", [ "match", ["get", "annee"], ["NULL"], false, true ], [ "step", ["get", "annee"], "#d1cf8f", 1945, "#5f9189", 1975, "#ff00ff" ], "#00A5AD" // The problem is here : Maplibre (Mapbox too) doesn't recognize fallback value (= else) ]