SIG

Operaciones de la clase Geometry

José Samos Jiménez
()
Dpto. LSI
Universidad de Granada

Citar y Licencia: https://doi.org/10.6084/m9.figshare.27601449.v2

Vídeo: https://youtu.be/57Y0_HBtCwA

La clase Geometry

Operaciones

Grupo Funciones
Relaciones espaciales ST_Contains, ST_Disjoint, ST_Equals, ST_Intersects, ST_Overlaps, ST_Touches, ST_Within
Proximidad y medición - ST_Buffer, ST_Distance
- ST_Area, ST_Length, ST_Perimeter
Transformaciones - ST_AsBinary, ST_AsText
- ST_Difference, ST_Intersection, ST_Union
- ST_Centroid, ST_ConvexHull, ST_Envelope
Operaciones adicionales (no OGC) ST_AsGeoJSON, ST_Simplify, ST_Transform

Relaciones espaciales: polígonos

Obtención y selección de relaciones

CREATE TABLE poligonos (
    id SERIAL PRIMARY KEY,
    geom GEOMETRY(POLYGON, 4326)  
);

INSERT INTO poligonos (geom) VALUES
  (ST_GeomFromText('POLYGON((0 0, 0 4, 4 4, 4 0, 0 0))', 4326)),
  (ST_GeomFromText('POLYGON((1 1, 1 3, 3 3, 3 1, 1 1))', 4326)),
  (ST_GeomFromText('POLYGON((3 3, 3 5, 5 5, 5 3, 3 3))', 4326)),
  (ST_GeomFromText('POLYGON((4 0, 4 1, 5 1, 5 0, 4 0))', 4326));

SELECT * 
FROM
 (SELECT DISTINCT ON 
   (r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within) 
   r.id1, r.id2, r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within
  FROM 
   (SELECT a.id AS id1, b.id AS id2,
           ST_Contains(a.geom, b.geom) AS contains,
           ST_Disjoint(a.geom, b.geom) AS disjoint,
           ST_Equals(a.geom, b.geom) AS equals,
           ST_Intersects(a.geom, b.geom) AS intersects,
           ST_Overlaps(a.geom, b.geom) AS overlaps,
           ST_Touches(a.geom, b.geom) AS touches,
           ST_Within(a.geom, b.geom) AS within
    FROM poligonos a, poligonos b
   ) AS r
  ORDER BY r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within,
           r.id1, r.id2
 ) AS q
ORDER BY id1, id2;

Combinaciones sin repetición

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 True False True True False False True
1 2 True False False True False False False
1 3 False False False True True False False
1 4 False False False True False True False
2 1 False False False True False False True
2 4 False True False False False False False

Relaciones espaciales: ST_Contains

SELECT a.id AS id1, b.id AS id2
FROM poligonos a JOIN poligonos b ON ST_Contains(a.geom, b.geom)
WHERE a.id <> b.id;
id1 id2
1 2

Relaciones espaciales: ST_Disjoint

SELECT a.id AS id1, b.id AS id2
FROM poligonos a JOIN poligonos b ON ST_Disjoint(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
2 4
3 4

Relaciones espaciales: ST_Equals

SELECT a.id AS id1, b.id AS id2
FROM poligonos a JOIN poligonos b ON ST_Equals(a.geom, b.geom)
WHERE a.id <= b.id;
id1 id2
1 1
2 2
3 3
4 4

Relaciones espaciales: ST_Intersects

SELECT a.id AS id1, b.id AS id2
FROM poligonos a JOIN poligonos b ON ST_Intersects(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
1 2
1 3
1 4
2 3

Relaciones espaciales: ST_Overlaps

SELECT a.id AS id1, b.id AS id2
FROM poligonos a JOIN poligonos b ON ST_Overlaps(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
1 3

Relaciones espaciales: ST_Touches

SELECT a.id AS id1, b.id AS id2
FROM poligonos a JOIN poligonos b ON ST_Touches(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
1 4
2 3

Relaciones espaciales: ST_Within

SELECT a.id AS id1, b.id AS id2
FROM poligonos a JOIN poligonos b ON ST_Within(a.geom, b.geom)
WHERE a.id <> b.id;
id1 id2
2 1

Relaciones espaciales: líneas

Obtención y selección de relaciones

CREATE TABLE lineas (
    id SERIAL PRIMARY KEY,
    geom GEOMETRY(LINESTRING, 4326)
);

INSERT INTO lineas (geom) VALUES
   (ST_GeomFromText('LINESTRING(2 -1, 2 5)', 4326)),
   (ST_GeomFromText('LINESTRING(0 -1, 3 -1)', 4326)),
   (ST_GeomFromText('LINESTRING(-1 4, 5 4)', 4326)),
   (ST_GeomFromText('LINESTRING(2 0.5, 2 3.5)', 4326)),
   (ST_GeomFromText('LINESTRING(2.5 -1, 5 -1)', 4326));
   
SELECT * 
FROM
 (SELECT DISTINCT ON 
   (r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within) 
   r.id1, r.id2, r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within
  FROM 
   (SELECT a.id AS id1, b.id AS id2,
           ST_Contains(a.geom, b.geom) AS contains,
           ST_Disjoint(a.geom, b.geom) AS disjoint,
           ST_Equals(a.geom, b.geom) AS equals,
           ST_Intersects(a.geom, b.geom) AS intersects,
           ST_Overlaps(a.geom, b.geom) AS overlaps,
           ST_Touches(a.geom, b.geom) AS touches,
           ST_Within(a.geom, b.geom) AS within
    FROM lineas a, lineas b
   ) AS r
  ORDER BY r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within,
           r.id1, r.id2
 ) AS q
ORDER BY id1, id2;

Combinaciones sin repetición

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 True False True True False False True
1 2 False False False True False True False
1 3 False False False True False False False
1 4 True False False True False False False
1 5 False True False False False False False
2 5 False False False True True False False
4 1 False False False True False False True

Relaciones espaciales: ST_Contains

SELECT a.id AS id1, b.id AS id2
FROM lineas a JOIN lineas b ON ST_Contains(a.geom, b.geom)
WHERE a.id <> b.id;
id1 id2
1 4

Relaciones espaciales: ST_Disjoint

SELECT a.id AS id1, b.id AS id2
FROM lineas a JOIN lineas b ON ST_Disjoint(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
1 5
2 3
2 4
3 4
3 5
4 5

Relaciones espaciales: ST_Equals

SELECT a.id AS id1, b.id AS id2
FROM lineas a JOIN lineas b ON ST_Equals(a.geom, b.geom)
WHERE a.id <= b.id;
id1 id2
1 1
2 2
3 3
4 4
5 5

Relaciones espaciales: ST_Intersects

SELECT a.id AS id1, b.id AS id2
FROM lineas a JOIN lineas b ON ST_Intersects(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
1 2
1 3
1 4
2 5

Relaciones espaciales: ST_Overlaps

SELECT a.id AS id1, b.id AS id2
FROM lineas a JOIN lineas b ON ST_Overlaps(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
2 5

Relaciones espaciales: ST_Touches

SELECT a.id AS id1, b.id AS id2
FROM lineas a JOIN lineas b ON ST_Touches(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
1 2

Relaciones espaciales: ST_Within

SELECT a.id AS id1, b.id AS id2
FROM lineas a JOIN lineas b ON ST_Within(a.geom, b.geom)
WHERE a.id <> b.id;
id1 id2
4 1

Relaciones espaciales: puntos

Obtención y selección de relaciones

CREATE TABLE puntos (
    id SERIAL PRIMARY KEY,
    geom GEOMETRY(POINT, 4326)
);

INSERT INTO puntos (geom) VALUES
   (ST_GeomFromText('POINT(2 0)', 4326)),
   (ST_GeomFromText('POINT(4 0)', 4326)),
   (ST_GeomFromText('POINT(3 -1)', 4326)),
   (ST_GeomFromText('POINT(2.5 1.5)', 4326));
   
SELECT * 
FROM
 (SELECT DISTINCT ON 
   (r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within) 
   r.id1, r.id2, r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within
  FROM 
   (SELECT a.id AS id1, b.id AS id2,
           ST_Contains(a.geom, b.geom) AS contains,
           ST_Disjoint(a.geom, b.geom) AS disjoint,
           ST_Equals(a.geom, b.geom) AS equals,
           ST_Intersects(a.geom, b.geom) AS intersects,
           ST_Overlaps(a.geom, b.geom) AS overlaps,
           ST_Touches(a.geom, b.geom) AS touches,
           ST_Within(a.geom, b.geom) AS within
    FROM puntos a, puntos b
   ) AS r
  ORDER BY r.contains, r.disjoint, r.equals, r.intersects, r.overlaps, r.touches, r.within,
           r.id1, r.id2
 ) AS q
ORDER BY id1, id2;

Combinaciones sin repetición

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 True False True True False False True
1 2 False True False False False False False

Relaciones espaciales: ST_Disjoint

SELECT a.id AS id1, b.id AS id2
FROM puntos a JOIN puntos b ON ST_Disjoint(a.geom, b.geom)
WHERE a.id < b.id;
id1 id2
1 2
1 3
1 4
2 3
2 4
3 4

Relaciones espaciales: ST_Equals

SELECT a.id AS id1, b.id AS id2
FROM puntos a JOIN puntos b ON ST_Equals(a.geom, b.geom)
WHERE a.id <= b.id;
id1 id2
1 1
2 2
3 3
4 4

Relaciones espaciales: puntos, líneas y polígonos

Polígonos y líneas

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 False False False True False False False
1 2 False True False False False False False
1 3 False False False True False True False
1 4 True False False True False False False

Líneas y polígonos

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 False False False True False False False
1 3 False True False False False False False
3 1 False False False True False True False
4 1 False False False True False False True

Polígonos y puntos

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 False False False True False True False
1 3 False True False False False False False
1 4 True False False True False False False

Puntos y polígonos

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 False False False True False True False
1 2 False True False False False False False
4 1 False False False True False False True

Líneas y puntos

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 True False False True False False False
1 2 False True False False False False False
2 3 False False False True False True False

Puntos y líneas

id1 id2 contains disjoint equals intersects overlaps touches within
1 1 False False False True False False True
1 2 False True False False False False False
3 2 False False False True False True False

Proximidad y medición


Grupo Funciones
Relaciones espaciales ST_Contains, ST_Disjoint, ST_Equals, ST_Intersects, ST_Overlaps, ST_Touches, ST_Within
Proximidad y medición - ST_Buffer, ST_Distance
- ST_Area, ST_Length, ST_Perimeter
Transformaciones - ST_AsBinary, ST_AsText
- ST_Difference, ST_Intersection, ST_Union
- ST_Centroid, ST_ConvexHull, ST_Envelope
Operaciones adicionales (no OGC) ST_AsGeoJSON, ST_Simplify, ST_Transform

ST_Buffer: obtención

SELECT 'Punto' AS tipo, 
       id, 
       ST_Buffer(ST_Transform(geom, 3857), 100000) AS geom
FROM puntos
WHERE id = 1
UNION ALL
SELECT 'Línea' AS tipo, 
       id, 
       ST_Buffer(ST_Transform(geom, 3857), 50000) AS geom
FROM lineas
WHERE id = 3
UNION ALL
SELECT 'Polígono' AS tipo, 
       id, 
       ST_Buffer(ST_Transform(geom, 3857), -20000) AS geom
FROM poligonos
WHERE id = 2;

ST_Buffer: resultado

ST_Distance: objetos

ST_Distance: obtención

SELECT *
FROM 
  (SELECT 
      'pu.lí' AS tipo,
      p.id AS id1,
      l.id AS id2,
      ST_Distance(ST_Transform(p.geom, 3857), 
                  ST_Transform(l.geom, 3857)) AS distancia_m
  FROM 
      puntos p,
      lineas l
  
  UNION ALL
  
  SELECT 
      'pu.po' AS tipo,
      p.id AS id1,
      pol.id AS id2,
      ST_Distance(ST_Transform(p.geom, 3857), 
                  ST_Transform(pol.geom, 3857)) AS distancia_m
  FROM 
      puntos p,
      poligonos pol
  
  UNION ALL
  
  SELECT 
      'lí.po' AS tipo,
      l.id AS id1,
      pol.id AS id2,
      ST_Distance(ST_Transform(l.geom, 3857), 
                  ST_Transform(pol.geom, 3857)) AS distancia_m
  FROM 
      lineas l,
      poligonos pol
  
  UNION ALL
  
  SELECT 
      'pu.pu' AS tipo,
      p1.id AS id1,
      p2.id AS id2,
      ST_Distance(ST_Transform(p1.geom, 3857), 
                  ST_Transform(p2.geom, 3857)) AS distancia_m
  FROM 
      puntos p1,
      puntos p2
  WHERE 
      p1.id < p2.id
  
  UNION ALL
  
  SELECT 
      'lí.lí' AS tipo,
      l1.id AS id1,
      l2.id AS id2,
      ST_Distance(ST_Transform(l1.geom, 3857), 
                  ST_Transform(l2.geom, 3857)) AS distancia_m
  FROM 
      lineas l1,
      lineas l2
  WHERE 
      l1.id < l2.id
  
  UNION ALL
  
  SELECT 
      'po.po' AS tipo,
      pol1.id AS id1,
      pol2.id AS id2,
      ST_Distance(ST_Transform(pol1.geom, 3857), 
                  ST_Transform(pol2.geom, 3857)) AS distancia_m
  FROM 
      poligonos pol1,
      poligonos pol2
  WHERE 
      pol1.id < pol2.id)
WHERE distancia_m > 0
ORDER BY tipo DESC, id1, id2;

ST_Distance: resultado

tipo id1 id2 distancia_m
pu.pu 1 2 222638.98
pu.pu 1 3 157433.53
pu.pu 1 4 176029.67
pu.pu 2 3 157433.53
pu.pu 2 4 236157.79
pu.pu 3 4 283834.38
pu.po 1 2 111325.14
pu.po 1 3 352168.01
pu.po 1 4 222638.98
pu.po 2 2 157433.53
pu.po 2 3 334111.17
pu.po 3 1 111325.14
pu.po 3 2 222650.29
pu.po 3 3 445436.31
pu.po 3 4 157433.53
pu.po 4 3 176138.34
pu.po 4 4 176015.82
pu.lí 1 2 111325.14
pu.lí 1 3 445640.11
tipo id1 id2 distancia_m
pu.lí 1 4 55660.45
pu.lí 1 5 124464.03
pu.lí 2 1 222638.98
pu.lí 2 2 157433.53
pu.lí 2 3 445640.11
pu.lí 2 4 229491.18
pu.lí 2 5 111325.14
pu.lí 3 1 111319.49
pu.lí 3 3 556965.25
pu.lí 3 4 200689.36
pu.lí 4 1 55659.75
pu.lí 4 2 278323.46
pu.lí 4 3 278641.80
pu.lí 4 4 55659.75
pu.lí 4 5 278323.46
po.po 2 4 111319.49
po.po 3 4 222786.03
lí.po 1 3 111319.49
lí.po 1 4 222638.98
tipo id1 id2 distancia_m
lí.po 2 1 111325.14
lí.po 2 2 222650.29
lí.po 2 3 445436.31
lí.po 2 4 157433.53
lí.po 3 2 111528.94
lí.po 3 4 334314.97
lí.po 4 3 111319.49
lí.po 4 4 222638.98
lí.po 5 1 111325.14
lí.po 5 2 222650.29
lí.po 5 3 445436.31
lí.po 5 4 111325.14
lí.lí 1 5 55659.75
lí.lí 2 3 556965.25
lí.lí 2 4 166985.59
lí.lí 3 4 55779.35
lí.lí 3 5 556965.25
lí.lí 4 5 176017.60

ST_Area, ST_Length, ST_Perimeter: obtención

SELECT * 
FROM
  (SELECT 
      'Punto' AS geometria,
      p.id,
      ST_Area(ST_Transform(p.geom, 3857)) AS area_m2,
      ST_Length(ST_Transform(p.geom, 3857)) AS length_m,
      ST_Perimeter(ST_Transform(p.geom, 3857)) AS perimeter_m
  FROM 
      puntos p
  
  UNION ALL
  
  SELECT 
      'Línea' AS geometria,
      l.id,
      ST_Area(ST_Transform(l.geom, 3857)) AS area_m2,
      ST_Length(ST_Transform(l.geom, 3857)) AS length_m,
      ST_Perimeter(ST_Transform(l.geom, 3857)) AS perimeter_m
  FROM 
      lineas l
  
  UNION ALL
  
  SELECT 
      'Polígono' AS geometria,
      pol.id,
      ST_Area(ST_Transform(pol.geom, 3857)) AS area_m2,
      ST_Length(ST_Transform(pol.geom, 3857)) AS length_m,
      ST_Perimeter(ST_Transform(pol.geom, 3857)) AS perimeter_m
  FROM 
      poligonos pol)
ORDER BY geometria, id;

ST_Area, ST_Length, ST_Perimeter: resultado

geometria id area_m2 length_m perimeter_m
Línea 1 0 668630.4 0.0
Línea 2 0 333958.5 0.0
Línea 3 0 667916.9 0.0
Línea 4 0 334200.3 0.0
Línea 5 0 278298.7 0.0
Polígono 1 198433720336 0.0 1781836.1
Polígono 2 49600854505 0.0 890850.0
Polígono 3 49691703975 0.0 891666.1
Polígono 4 12392658216 0.0 445289.3
Punto 1 0 0.0 0.0
Punto 2 0 0.0 0.0
Punto 3 0 0.0 0.0
Punto 4 0 0.0 0.0

Transformaciones (i)


Grupo Funciones
Relaciones espaciales ST_Contains, ST_Disjoint, ST_Equals, ST_Intersects, ST_Overlaps, ST_Touches, ST_Within
Proximidad y medición - ST_Buffer, ST_Distance
- ST_Area, ST_Length, ST_Perimeter
Transformaciones - ST_AsBinary, ST_AsText
- ST_Difference, ST_Intersection, ST_Union
- ST_Centroid, ST_ConvexHull, ST_Envelope
Operaciones adicionales (no OGC) ST_AsGeoJSON, ST_Simplify, ST_Transform

ST_Difference: polígono y polígono

SELECT 
    pol1.id AS id,
    ST_Difference(pol1.geom, pol2.geom) AS geom
FROM 
    poligonos pol1,
    poligonos pol2
WHERE 
    pol1.id = 1 AND pol2.id = 3;

ST_Difference: línea y línea

SELECT 
    lin1.id AS id,
    ST_Difference(lin1.geom, lin2.geom) AS geom
FROM 
    lineas lin1,
    lineas lin2
WHERE 
    lin1.id = 1 AND lin2.id = 4;

id geom
1 MULTILINESTRING((2 -1,2 0.5),(2 3.5,2 5))

ST_Difference: líneas y polígono

SELECT 
    lin.id AS id,
    ST_Difference(lin.geom, pol.geom) AS geom
FROM 
    lineas lin,
    poligonos pol
WHERE 
    pol.id = 1;

id geom
1 MULTILINESTRING((2 -1,2 0),(2 4,2 5))
2 LINESTRING(0 -1,3 -1)
3 MULTILINESTRING((-1 4,0 4),(4 4,5 4))
4 LINESTRING EMPTY
5 LINESTRING(2.5 -1,5 -1)

ST_Difference: polígono y línea (i)

SELECT 
    pol.id AS id,
    ST_Difference(pol.geom, lin.geom) AS geom
FROM 
    lineas lin,
    poligonos pol
WHERE 
    pol.id = 1 AND lin.id = 1;

ST_Difference: polígono y línea (y ii)

SELECT 
    id, 
    ST_AsText(geom) AS geom
FROM 
    poligonos
WHERE 
    id = 1

UNION ALL

SELECT 
    pol.id AS id,
    ST_AsText(ST_Difference(pol.geom, lin.geom)) AS geom
FROM 
    lineas lin,
    poligonos pol
WHERE 
    pol.id = 1 AND lin.id = 1;
id geom
1 POLYGON((0 0,0 4,4 4,4 0,0 0))
1 POLYGON((0 4,2 4,4 4,4 0,2 0,0 0,0 4))

ST_Difference: puntos y polígono

SELECT 
    pun.id AS id,
    ST_Difference(pun.geom, pol.geom) AS geom
FROM 
    puntos pun,
    poligonos pol
WHERE 
    pol.id = 1;

id geom
1 POINT EMPTY
2 POINT EMPTY
3 POINT(3 -1)
4 POINT EMPTY

ST_Difference: puntos y línea (i)

SELECT 
    pun.id AS id,
    ST_Difference(pun.geom, lin.geom) AS geom
FROM 
    puntos pun,
    lineas lin
WHERE 
    lin.id = 1;

id geom
1 POINT EMPTY
2 POINT(4 0)
3 POINT(3 -1)
4 POINT(2.5 1.5)

ST_Difference: puntos y línea (y ii)

SELECT 
    pun.id AS id,
    ST_Difference(pun.geom, lin.geom) AS geom
FROM 
    puntos pun,
    lineas lin
WHERE 
    lin.id = 2;

id geom
1 POINT(2 0)
2 POINT(4 0)
3 POINT EMPTY
4 POINT(2.5 1.5)

Transformaciones (y ii)


Grupo Funciones
Relaciones espaciales ST_Contains, ST_Disjoint, ST_Equals, ST_Intersects, ST_Overlaps, ST_Touches, ST_Within
Proximidad y medición - ST_Buffer, ST_Distance
- ST_Area, ST_Length, ST_Perimeter
Transformaciones - ST_AsBinary, ST_AsText
- ST_Difference, ST_Intersection, ST_Union
- ST_Centroid, ST_ConvexHull, ST_Envelope
Operaciones adicionales (no OGC) ST_AsGeoJSON, ST_Simplify, ST_Transform

ST_Centroid: polígonos (i)

SELECT 
    id,
    ST_Centroid(geom) AS geom
FROM
    poligonos;

ST_Centroid: polígonos (y ii)

SELECT 
    1 AS id,
    ST_Centroid(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        poligonos);

ST_Centroid: líneas (i)

SELECT 
    id,
    ST_Centroid(geom) AS geom
FROM
    lineas;

ST_Centroid: líneas (y ii)

SELECT 
    1 AS id,
    ST_Centroid(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        lineas);

ST_Centroid: puntos

SELECT 
    1 AS id,
    ST_Centroid(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        puntos);

ST_ConvexHull: polígonos

SELECT 
    1 AS id,
    ST_ConvexHull(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        poligonos);

ST_ConvexHull: líneas

SELECT 
    1 AS id,
    ST_ConvexHull(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        lineas);

ST_ConvexHull: puntos

SELECT 
    1 AS id,
    ST_ConvexHull(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        puntos);

ST_Envelope: polígonos

SELECT 
    1 AS id,
    ST_Envelope(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        poligonos);

ST_Envelope: líneas

SELECT 
    1 AS id,
    ST_Envelope(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        lineas);

ST_Envelope: puntos

SELECT 
    1 AS id,
    ST_Envelope(geom) AS geom
FROM
    (SELECT 
        ST_Union(geom) AS geom
    FROM 
        puntos);

Operaciones adicionales (no OGC)


Grupo Funciones
Relaciones espaciales ST_Contains, ST_Disjoint, ST_Equals, ST_Intersects, ST_Overlaps, ST_Touches, ST_Within
Proximidad y medición - ST_Buffer, ST_Distance
- ST_Area, ST_Length, ST_Perimeter
Transformaciones - ST_AsBinary, ST_AsText
- ST_Difference, ST_Intersection, ST_Union
- ST_Centroid, ST_ConvexHull, ST_Envelope
Operaciones adicionales (no OGC) ST_AsGeoJSON, ST_Simplify, ST_Transform

Conclusiones

Grupo Funciones
Relaciones espaciales ST_Contains, ST_Disjoint, ST_Equals, ST_Intersects, ST_Overlaps, ST_Touches, ST_Within
Proximidad y medición - ST_Buffer, ST_Distance
- ST_Area, ST_Length, ST_Perimeter
Transformaciones - ST_AsBinary, ST_AsText
- ST_Difference, ST_Intersection, ST_Union
- ST_Centroid, ST_ConvexHull, ST_Envelope
Operaciones adicionales (no OGC) ST_AsGeoJSON, ST_Simplify, ST_Transform