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PostGIS 1.5.8 Manual227 / 310SELECT poly.gid, ST_Multi(ST_Buffer(ST_Intersection(country.the_geom, poly.the_geom),0.0)) As clipped_geomFROM countryINNER JOIN polyON ST_Intersects(country.the_geom, poly.the_geom)WHERE Not ST_IsEmpty(ST_Buffer(ST_Intersection(country.the_geom, poly.the_geom),0.0));See AlsoST_Difference, ST_Dimension, ST_Dump, ST_SymDifference, ST_Intersects, ST_Multi7.9.11 ST_LineToCurveST_LineToCurve — Converts a LINESTRING/POLYGON to a CIRCULARSTRING, CURVED POLYGONSynopsisgeometry ST_LineToCurve(geometry geomANoncircular);DescriptionConverts plain LINESTRING/POLYGONS to CIRCULAR STRINGs and Curved Polygons. Note much fewer points are neededto describe the curved equivalent.Availability: 1.2.2?This function supports 3d and will not drop the z-index.This method supports Circular Strings and CurvesExamplesSELECT ST_AsText(ST_LineToCurve(foo.the_geom)) As curvedastext,ST_AsText(foo.the_geom) Asnon_curvedastextFROM (SELECT ST_Buffer(’POINT(1 3)’::geometry, 3) As the_geom) As foo;←↪curvedatextnon_curvedastext------------------------------------------------------------------| ←↪-----------------------------------------------------------------CURVEPOLYGON(CIRCULARSTRING(4 3,3.12132034355964 0.878679656440359, | POLYGON((4 ←↪3,3.94235584120969 2.41472903395162,3.77163859753386 1.851949702904731 0,-1.12132034355965 5.12132034355963,4 3)) | ,3.49440883690764 ←↪1.33328930094119,3.12132034355964 0.878679656440359,| 2.66671069905881 ←↪0.505591163092366,2.14805029709527 0.228361402466141,| 1.58527096604839 0.0576441587903094,1 0,| 0.414729033951621 ←↪0.0576441587903077,-0.148050297095264 ←↪0.228361402466137,| -0.666710699058802 ←↪0.505591163092361,-1.12132034355964 0.878679656440353,| -1.49440883690763 ←↪1.33328930094119,-1.77163859753386 1.85194970290472