Polygon fill failing beyond zoom 11 #797

guillaumemichel · 2025-02-07T08:01:49Z

I tried generating a very simple map, only including water bodies (lakes) for switzerland-latest.osm.pbf, and it seems there is an issue when rendering lakes fill at a zoom level >= 11.

The screenshot comes from Lake Lucerne, Switzerland, but I can reproduce this for almost all lakes on the map. I am using tilemaker-server to render the tiles. I have also tried with MapLibre GL JS, which produces the same result, so I suspect the issue comes from the map generation rather than rendering.

Zoom 10

Zoom 11

Zoom 12

Zoom 13

The strange lines seem to come from somewhere close to the tile borders. Could it be possible that the polygon isn't complete (some missing lines in the polygon border)? The problem seems to come from polygon filling, since using the MapLibre line layer type works as expected (see below).

Here is the minimal working configuration to reproduce it. Maybe it is a simple configuration mistake and I am sorry in advance if it is the case.

config.json

{
  "layers": {
    "water": {
      "minzoom": 6,
      "maxzoom": 14,
      "simplify_below": 12,
      "simplify_level": 0.0003,
      "simplify_ratio": 2.0
    }
  },
  "settings": {
    "minzoom": 4,
    "maxzoom": 14,
    "basezoom": 14,
    "include_ids": false,
    "name": "Switzerland Lakes",
    "version": "0.1",
    "description": "Switzerland Lakes",
    "compress": "gzip"
  }
}

process.lua

node_keys = { "natural" }

function node_function(node) end

-- Process ways:
function way_function()
	local natural = Find("natural")
	-- -- Process water polygons (e.g. lakes, seas)
	if natural == "water" then
		-- Skip rivers, only process lakes
		if Find("water") == "river" then
			return
		end
		Layer("water")
		Attribute("class", "lake")
		MinZoom(6)
	end
end

index.html for the MapLibre line screenshot

<!DOCTYPE html>
<html>
<head>
    <title>Switzerland Lakes</title>
    <link href="https://unpkg.com/[email protected]/dist/maplibre-gl.css" rel="stylesheet" />
    <script src="https://unpkg.com/[email protected]/dist/maplibre-gl.js"></script>
    <style>
        #map { position: absolute; top: 0; bottom: 0; width: 100%; }
    </style>
</head>
<body>
    <div id="map"></div>
    <script>
        const style = {
            "version": 8,
            "name": "Water Only",
            "glyphs": "https://orangemug.github.io/font-glyphs/glyphs/{fontstack}/{range}.pbf",
            "sources": {
                "tilemaker-tiles": {
                    "type": "vector",
                    "tiles": ["http://localhost:8000/services/switzerland/tiles/{z}/{x}/{y}.pbf"], // mbtileserver
                    "maxzoom": 14
                }
            },
            "layers": [
                {
                    "id": "water-lakes-outline",
                    "type": "line",
                    "source": "tilemaker-tiles",
                    "source-layer": "water",
                    "filter": ["==", ["get", "class"], "lake"],
                    "paint": {
                        "line-color": "#a0c8f0", // Light blue
                        "line-width": 2
                    }
                },
            ]
        };

        // Initialize the map
        const map = new maplibregl.Map({
            container: 'map',
            style: style,
            center: [8.2275, 46.8182], // Switzerland
            zoom: 8,
        });
    </script>
</body>
</html>

I have built tilemaker from the latest commit, and am running arch linux 6.13.1-arch1-1 (btw).

edit: I just updated to the latest available boost version (boost-1.87.0-2-x86_64) and the issue persists.

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Polygon fill failing beyond zoom 11 #797

Polygon fill failing beyond zoom 11 #797

guillaumemichel commented Feb 7, 2025 •

edited

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Polygon fill failing beyond zoom 11 #797

Polygon fill failing beyond zoom 11 #797

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guillaumemichel commented Feb 7, 2025 • edited Loading

guillaumemichel commented Feb 7, 2025 •

edited

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