[postgis-users] why st_isclosed() is false?

[Birgit Laggner]

  Dear list,

perhaps somebody could clear things for me:

If I run the query below, the result is "false". But I don't understand 
why. I always thought, as long as there exists a continuous chain of 
start and end points, a MultiLineString would be closed. Am I wrong somehow?

Thanks and regards,

Birgit.


select st_isclosed(st_geomfromtext(
'MULTILINESTRING(
(3584442.63274253 5842172.41579578,
  3584358.9809     5842152.7361,
  3584355.23337321 5842153.70245931),
(3584355.23337321 5842153.70245931,
  3584355.23330909 5842153.70247585,
  3584355.23339452 5842153.70245382,
  3584355.23337321 5842153.70245931),
(3584355.23337321 5842153.70245931,
  3584348.03488658 5842155.55873215,
  3584345.68905341 5842155.07665686,
  3584343.82931858 5842154.69447615,
  3584340.46724669 5842152.9072508,
  3584338.14023057 5842151.67024508,
  3584328.33210257 5842146.45639614,
  3584009.05607027 5842072.59988407,
  3583887.98803815 5842042.75796404,
  3583790.05011806 5842106.6478841,
  3583790.05012    5842106.64788453,
  3583878.43617231 5842126.47539268,
  3584324.73120656 5842226.59207621,
  3584329.67415529 5842229.44269127,
  3584334.41005457 5842232.17390022,
  3584368.1119426  5842240.76423623,
  3584463.63629469 5842262.81966025,
  3584488.97911407 5842268.84731974),
(3584488.97911407 5842268.84731974,
  3584488.97978147 5842268.84747848,
  3584488.97978146 5842268.84747848,
  3584488.97911407 5842268.84731974),
(3584488.97911407 5842268.84731974,
  3584488.97890809 5842268.84727075,
  3584464.1099     5842262.3082,
  3584464.10990818 5842262.30817579,
  3584466.07027273 5842256.50678355,
  3584472.08934014 5842238.694295,
  3584472.08940751 5842238.69409565,
  3584489.545      5842187.037,
  3584489.5450305  5842187.03700481,
  3584489.54503071 5842187.03700417,
  3584526.86014482 5842192.92533864,
  3584514.30279074 5842190.12385218,
  3584495.65165472 5842186.30586817,
  3584480.67207071 5842180.87201217,
  3584458.64642469 5842176.18313362,
  3584458.64634269 5842176.18311617,
  3584442.63469631 5842172.41625542,
  3584442.63274253 5842172.41579578))',31467));