Demo rendering location_number as text

app/map_styles/polygon.xml

@@ -7,8 +7,19 @@
     </Style>
     <Style name="highlight">
         <Rule>
-            <PolygonSymbolizer fill="#4682B455" />
+            <Filter>[focus] = true</Filter>
+            <LineSymbolizer stroke="black" stroke-width="5" stroke-opacity="0.5" />
             <LineSymbolizer stroke="white" stroke-width="3" />
+            <TextSymbolizer face-name="DejaVu Sans Condensed Bold">
+                [location_number]
+            </TextSymbolizer>
+        </Rule>
+        <Rule>
+            <ElseFilter />
+            <LineSymbolizer stroke="black" stroke-width="0.3" />
+            <TextSymbolizer face-name="DejaVu Sans Condensed Bold">
+                [location_number]
+            </TextSymbolizer>
         </Rule>
     </Style>
     <Style name="size_storeys">

app/src/tile.js

@@ -21,7 +21,7 @@ const PROJ4_STRING = '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x
 
 // register datasource adapters for mapnik
 if (mapnik.register_default_input_plugins) mapnik.register_default_input_plugins();
-
+mapnik.register_default_fonts();
 
 const mercator = new SphericalMercator({
     size: TILE_SIZE

app/src/tileserver.js

@@ -25,8 +25,18 @@ router.get('/highlight/:z/:x/:y.png', function(req, res) {
     if(!geometry_id) res.status(400).send({error:'Bad parameter'})
     const bbox = get_bbox(req.params)
     const table_def = `(
-        select * from geometries
-        where geometry_id = ${geometry_id}
+        SELECT
+            (g.geometry_id = ${geometry_id}) as focus,
+            cast(
+                b.building_doc->>'location_number'
+                as text
+            ) as location_number,
+            g.geometry_geom
+        FROM
+            geometries as g,
+            buildings as b
+        WHERE
+            g.geometry_id = b.geometry_id
     ) as highlight`
     const style_def = ['highlight']
     render_tile(bbox, table_def, style_def, function(err, im) {