QGIS 2.2 and PostGIS geometry > 2d

qgis_postgis_geom.py

# QGIS 2.2 won't show 4d geometry (maybe not 3dm or 3dz either but I didn't test).
# If you don't actually need 4d and it's just an artifact of the data when you loaded
# it, use this python snippet to convert it to 2d and get your data showing up in 
# QGIS again. Use at your own risk. There is NO ERROR HANDLING HERE!

import psycopg2

db = psycopg2.connect(host='localhost', port='5432', database='#####',user='#####')
cursor = db.cursor()

# Customize as necessary to keep the tables where you need 4d
query = "SELECT f_table_schema, f_table_name AS table, f_geometry_column, srid, type FROM geometry_columns WHERE coord_dimension > 2 AND NOT f_table_name LIKE '%flowline%';"
cursor.execute(query)
rels = cursor.fetchall()

for schema, rel, geom, srid, gtype in rels:
    query = """ALTER TABLE {0}.{1} ALTER COLUMN {2} TYPE geometry({3},{4}) USING ST_Force2d({2});""".format(schema, rel, geom, gtype, srid)
    cursor.execute(query)
    db.commit()
    
cursor.close()
db.close()