How could I insert a 3-D LineString into PostGIS table?

Question

Using:

CREATE TABLE trajectories(
gid SERIAL PRIMARY KEY,
vehID VARCHAR(10),
state INTEGER,
geom geometry(MULTILINESTRING)
)

I get an error, for instance, after inserting:

INSERT INTO trajectories(vehid,state,geom)
VALUES(001140,2,ST_GeomFromText('MULTILINESTRING((1 2 3,4 5 6))'))

it gives:

Geometry has Z dimension but column does not.

How could I circumvent this error?

Answer 1

Using

-- DROP TABLE trajectories;

CREATE TABLE trajectories
(
  gid serial NOT NULL,
  vehid character varying(10),
  state integer,
  geom geometry(MultiLineStringZ),
  CONSTRAINT trajectories_pkey PRIMARY KEY (gid)
)
WITH (
  OIDS=FALSE
);
ALTER TABLE trajectories
  OWNER TO postgres;

Your INSERT will be ok.

Indeed: in your code the geom column does not have Z dimension.

Answer 2

Check if your column type is geometry if so you need to convert into

ALTER TABLE trajectories 
  ALTER COLUMN geom TYPE geometry(MultiLineStringZ)
    USING ST_Force_3D(geom);

This will force the column to hold Z value.