I’m trying to update geometry table using the following command but get

parse error – invalid  geometry
HINT: “MULTIPOINT(“ <--  parse error at position 11 within geometry

    Update geo_table
    Set geom =ST_ConvexHull(
                                ST_GeomFromText('MULTIPOINT(co_ord_string)', 4326));
    Id =1234;

originally I created this data with a perl script something like

     insert into geo_table (stuff,date, co_ord_string,geom) values (‘Hello’,’02-07-2018 00:00:00’, T_ConvexHull(ST_GeomFromText('MULTIPOINT($co_ord_string)', 4326));

The co_ord_string is a series of long lat points separated by a comma. These don’t create perfect polygons as they may contain internal points but using ST_ConvexHull a polygon is created.

Only by viewing the data in QGIS I can see there are errors in the original coordinates that need manually editing (Missing minus signs some points or other issues ) and the geometry recreating.

What is the correct syntax?

  • What is in coordstring? – Ian Turton Jul 3 '18 at 7:16
  • “MULTIPOINT(“, ‘Hello’ These are not ASCII quotes. Did you copy/paste everything correctly into this question? – CL. Jul 3 '18 at 11:16
  • @Ian Turton co_ord_string is the column name containing a list of Long Lat points separated by a comma. If this value is manually copied the query works. – Holly Jul 4 '18 at 17:47
  • @CL the Non ASCII Quotes are due to having to email question home in order to post I forgot to replace them sorry – Holly Jul 4 '18 at 17:48

I found out how to do this by concatenating the query so it gets the values from the database object co_ord_string

UPDATE geo_table
SET geom =ST_ConvexHull(
 ST_GeomFromText('MULTIPOINT(' || co_ord_string|| ')', 4326)
WHERE Id =1234;
  • 1
    You can accept your own answer with the checkbox – BERA Aug 9 '18 at 9:03

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