Hello,
one of our project needs a series of linestrings that link points of
the same type. The data does not have any specific order, but the
lines should be simple (not tangled) and the points ordered by
proximity. Do you have any suggestion?
This is the query I use now, but it doesn't work.
SELECT id_group, -- to have a numeric key
groupname,
MakeLine(wkb_geometry) AS geom
FROM (
SELECT e.id_group,
o.groupname,
e.survey_year,
g.wkb_geometry
FROM test.monksandnuns AS e,
public.capoluoghi AS g,
test.regclrg_groups A o
WHERE e.geo_code = g.istat_com
AND e.country = 'I'
AND e.groupname = o.denom_groupname
GROUP BY g.ogc_fid, g.wkb_geometry, e.survey_year, o.id_group,
e.groupname, e.congregazione
UNION -- we have two countries
SELECT e.id_group,
o.groupname,
e.survey_year,
wkb_geometry
FROM test.monksandnuns AS e,
public.france_cheflf_m_l2_point_wgs AS g,
test.regclrg_groups AS o
WHERE e.geo_code = g.depcom
AND e.country = 'F'
AND e.groupname = o.denom_groupname
GROUP BY g.ogc_fid, g.wkb_geometry, e.survey_year, o.id_group,
e.groupname, e.congregazione
) AS sedi
WHERE survey_year = 1829
GROUP BY groupname, id_group
;
is there a way to obtain:
* a polyline for every group;
* simple line?
TIA
c
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