Class/subclass issue when adding GeoJSON to tilemaker.

[rebrancher]

Hello - I am adding a geoJson of subway lines my maptiles of NYC. When I render the map, I see the geoJSON addition fine, however, the class is somehow "ocean." I have a feeling the answer may be a bit obvious - but I am having a hard time figuring it out, any help would be appreciated

Please see below for the config file:

"layers": {
	"place":            { "minzoom":  0, "maxzoom": 14 },
	"boundary":         { "minzoom":  0, "maxzoom": 14, "simplify_below": 12, "simplify_level": 0.0003, "simplify_ratio": 2 },

	"poi":              { "minzoom": 12, "maxzoom": 14 },
	"poi_detail":       { "minzoom": 14, "maxzoom": 14, "write_to": "poi"},

	"housenumber":      { "minzoom": 14, "maxzoom": 14 },

	"waterway":         { "minzoom":  8,  "maxzoom": 14, "simplify_below": 12, "simplify_level": 0.0003, "simplify_ratio": 2 },
	"waterway_detail":  { "minzoom": 12,  "maxzoom": 14, "write_to": "waterway" },

	"transportation":             { "minzoom": 4,  "maxzoom": 14, "simplify_below": 13, "simplify_level": 0.0003 },
	"transportation_name":        { "minzoom": 8,  "maxzoom": 14 },
	"transportation_name_mid":    { "minzoom": 12, "maxzoom": 14, "write_to": "transportation_name" },
	"transportation_name_detail": { "minzoom": 14, "maxzoom": 14, "write_to": "transportation_name" },

	"building":          { "minzoom": 13, "maxzoom": 14 },

	"water":             { "minzoom": 6,  "maxzoom": 14, "simplify_below": 12, "simplify_level": 0.0003, "simplify_ratio": 2},
	"ocean":             { "minzoom": 0,  "maxzoom": 14, "source": "coastline/water_polygons.shp", "filter_below": 12, "filter_area": 0.5, "simplify_below": 13, "simplify_level": 0.0001, "simplify_ratio": 2, "write_to": "water" },
	"water_name":        { "minzoom": 14, "maxzoom": 14 },
	"water_name_detail": { "minzoom": 14, "maxzoom": 14, "write_to": "water_name" },

	"aeroway":           { "minzoom": 11, "maxzoom": 14 },
	"aerodrome_label":   { "minzoom": 10, "maxzoom": 14 },
	"park":              { "minzoom": 11, "maxzoom": 14 },
	"landuse":           { "minzoom":  4, "maxzoom": 14, "simplify_below": 13, "simplify_level": 0.0003, "simplify_ratio": 2 },
	"urban_areas":       { "minzoom":  4, "maxzoom":  8, "source": "landcover/ne_10m_urban_areas/ne_10m_urban_areas.shp", "source_columns": ["featurecla"], "simplify_below": 7, "simplify_level": 0.0003, "simplify_ratio": 2, "write_to": "landuse" },
	"landcover":         { "minzoom":  0, "maxzoom": 14, "simplify_below": 13, "simplify_level": 0.0003, "simplify_ratio": 2 },
	"ice_shelf":         { "minzoom":  0, "maxzoom":  9, "source": "landcover/ne_10m_antarctic_ice_shelves_polys/ne_10m_antarctic_ice_shelves_polys.shp", "source_columns": ["featurecla"], "simplify_below": 13, "simplify_level": 0.0005, "write_to": "landcover" },
	"glacier":           { "minzoom":  2, "maxzoom":  9, "source": "landcover/ne_10m_glaciated_areas/ne_10m_glaciated_areas.shp", "source_columns": ["featurecla"], "simplify_below": 13, "simplify_level": 0.0005, "write_to": "landcover" },
	"mountain_peak":     { "minzoom": 11, "maxzoom": 14 },
	"subways":           { "minzoom": 11, "maxzoom": 14, "source": "geoJson/SubwayLines.geojson", "source_columns": ["name"]}
},
"settings": {
	"minzoom": 0,
	"maxzoom": 14,
	"basezoom": 14,
	"include_ids": false,
	"combine_below": 14,
	"name": "Tilemaker to OpenMapTiles schema",
	"version": "3.0",
	"description": "Tile config based on OpenMapTiles schema",
	"compress": "gzip",
	"filemetadata": {
		"tilejson": "2.0.0", 
		"scheme": "xyz", 
		"type": "baselayer", 
		"format": "pbf", 
        "tiles": ["https://example.com/liechtenstein/{z}/{x}/{y}.pbf"]
	}
}

[cldellow]

You probably want to tweak your attribute_function. It gets called when processing GeoJSON/shapefiles - you receive the layer name and the attributes, and decide which attributes you want to write out.

The openmaptiles profile defaults to ocean, so I'm guessing you've maybe started from that file:

tilemaker/resources/process-openmaptiles.lua

Lines 654 to 665 in 172d133

	-- Remap coastlines
	function attribute_function(attr,layer)
	if attr["featurecla"]=="Glaciated areas" then
	return { subclass="glacier" }
	elseif attr["featurecla"]=="Antarctic Ice Shelf" then
	return { subclass="ice_shelf" }
	elseif attr["featurecla"]=="Urban area" then
	return { class="residential" }
	else
	return { class="ocean" }
	end
	end

[rebrancher]

Thanks - that was the right place. If anyone else is struggling with these and comes across this I simply printed out the inputs to write a new elseif, see below:

  function attribute_function(attr, layer)
      -- Print the layer
      print("Layer:", layer)
  
      -- Print all key-value pairs in attr
      for key, value in pairs(attr) do
          print("attr[" .. key .. "] =", value)
      end
  
      if attr["featurecla"] == "Glaciated areas" then
          return { subclass = "glacier" }
      elseif attr["featurecla"] == "Antarctic Ice Shelf" then
          return { subclass = "ice_shelf" }
      elseif attr["featurecla"] == "Urban area" then
          return { class = "residential" }
      else
          return { class = "ocean" }
      end
  end

[systemed]

I've tweaked this in c490b5c so that you can just add GeoJSON files to the default config, and it won't assume they're the ocean.