Geometry Types

Geobase’s tile server supports all standard PostGIS geometry types. Here’s a detailed breakdown of each type and how to work with them:

Point Geometries

POINT: Single coordinate pair representing a specific location
MULTIPOINT: Collection of points

-- Point example
SELECT ST_MakePoint(-122.4194, 37.7749) as geom;
 
-- MultiPoint example
SELECT ST_GeomFromText('MULTIPOINT(-122.4194 37.7749, -122.4184 37.7739)') as geom;

Line Geometries

LINESTRING: Series of connected points forming a line
MULTILINESTRING: Collection of linestrings

-- LineString example
SELECT ST_GeomFromText('LINESTRING(-122.4194 37.7749, -122.4184 37.7739)') as geom;
 
-- MultiLineString example
SELECT ST_GeomFromText('MULTILINESTRING(
    (-122.4194 37.7749, -122.4184 37.7739),
    (-122.4184 37.7739, -122.4174 37.7729)
)') as geom;

Polygon Geometries

POLYGON: Closed shape defined by a ring of coordinates
MULTIPOLYGON: Collection of polygons

-- Polygon example (must close the ring)
SELECT ST_GeomFromText('POLYGON((
    -122.4194 37.7749,
    -122.4184 37.7739,
    -122.4174 37.7729,
    -122.4194 37.7749
))') as geom;
 
-- MultiPolygon example
SELECT ST_GeomFromText('MULTIPOLYGON((
    (-122.4194 37.7749, -122.4184 37.7739, -122.4174 37.7729, -122.4194 37.7749)
),(
    (-122.4294 37.7849, -122.4284 37.7839, -122.4274 37.7829, -122.4294 37.7849)
))') as geom;

Geometry Collections

GEOMETRYCOLLECTION: Mixed collection of different geometry types

SELECT ST_GeomFromText('GEOMETRYCOLLECTION(
    POINT(-122.4194 37.7749),
    LINESTRING(-122.4194 37.7749, -122.4184 37.7739),
    POLYGON((-122.4194 37.7749, -122.4184 37.7739, -122.4174 37.7729, -122.4194 37.7749))
)') as geom;

MapLibre Layer Types

When displaying these geometries in MapLibre GL JS, use the appropriate layer type:

// For Point/MultiPoint geometries
map.addLayer({
    id: 'points-layer',
    type: 'circle',  // or 'symbol' for icons
    source: 'data-source',
    'source-layer': 'layer-name',
});
 
// For LineString/MultiLineString geometries
map.addLayer({
    id: 'lines-layer',
    type: 'line',
    source: 'data-source',
    'source-layer': 'layer-name',
});
 
// For Polygon/MultiPolygon geometries
map.addLayer({
    id: 'polygons-layer',
    type: 'fill',  // or 'fill-extrusion' for 3D
    source: 'data-source',
    'source-layer': 'layer-name',
});

Multi-geometry tile source with MapLibre

If your table has multiple geometries, you can filter the layer by the geometry type.

// Point
map.addLayer({
    id: 'points-layer',
    type: 'circle',
    source: 'data-source',
    'source-layer': 'layer-name',
    filter: ["==", "$type", "Point"] // or "==", "$type", "MultiPoint"
});
 
// LineString
map.addLayer({
    id: 'lines-layer',
    type: 'line',
    source: 'data-source',
    'source-layer': 'layer-name',
    filter: ["==", "$type", "LineString"]
});
 
// Polygon
map.addLayer({
    id: 'polygons-layer',
    type: 'fill',
    source: 'data-source',
    'source-layer': 'layer-name',
    filter: ["==", "$type", "Polygon"] // or "==", "$type", "MultiPolygon"
});

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