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Correct calculations of overlap and contains operations over polygons.

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This commit is contained in:
Teodor Sigaev 2009-07-28 09:48:00 +00:00
parent 1f4b046c18
commit 49475aab8d
5 changed files with 346 additions and 49 deletions
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252
src/backend/utils/adt/geo_ops.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/geo_ops.c,v 1.102 2009/06/23 16:25:02 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/geo_ops.c,v 1.103 2009/07/28 09:47:59 teodor Exp $
*
*-------------------------------------------------------------------------
*/
@ -66,6 +66,8 @@ static bool has_interpt_sl(LSEG *lseg, LINE *line);
static double dist_pl_internal(Point *pt, LINE *line);
static double dist_ps_internal(Point *pt, LSEG *lseg);
static Point *line_interpt_internal(LINE *l1, LINE *l2);
static bool lseg_inside_poly(Point *a, Point *b, POLYGON *poly, int start);
static Point* lseg_interpt_internal(LSEG *l1, LSEG *l2);
/*
@ -2352,15 +2354,9 @@ lseg_center(PG_FUNCTION_ARGS)
PG_RETURN_POINT_P(result);
}
/* lseg_interpt -
* Find the intersection point of two segments (if any).
*/
Datum
lseg_interpt(PG_FUNCTION_ARGS)
static Point*
lseg_interpt_internal(LSEG *l1, LSEG *l2)
{
LSEG *l1 = PG_GETARG_LSEG_P(0);
LSEG *l2 = PG_GETARG_LSEG_P(1);
Point *result;
LINE tmp1,
tmp2;
@ -2372,7 +2368,7 @@ lseg_interpt(PG_FUNCTION_ARGS)
line_construct_pts(&tmp2, &l2->p[0], &l2->p[1]);
result = line_interpt_internal(&tmp1, &tmp2);
if (!PointerIsValid(result))
PG_RETURN_NULL();
return NULL;
/*
* If the line intersection point isn't within l1 (or equivalently l2),
@ -2380,7 +2376,10 @@ lseg_interpt(PG_FUNCTION_ARGS)
*/
if (!on_ps_internal(result, l1) ||
!on_ps_internal(result, l2))
PG_RETURN_NULL();
{
pfree(result);
return NULL;
}
/*
* If there is an intersection, then check explicitly for matching
@ -2400,6 +2399,23 @@ lseg_interpt(PG_FUNCTION_ARGS)
result->y = l1->p[1].y;
}
return result;
}
/* lseg_interpt -
* Find the intersection point of two segments (if any).
*/
Datum
lseg_interpt(PG_FUNCTION_ARGS)
{
LSEG *l1 = PG_GETARG_LSEG_P(0);
LSEG *l2 = PG_GETARG_LSEG_P(1);
Point *result;
result = lseg_interpt_internal(l1, l2);
if (!PointerIsValid(result))
PG_RETURN_NULL();
PG_RETURN_POINT_P(result);
}
@ -3742,10 +3758,7 @@ poly_same(PG_FUNCTION_ARGS)
}
/*-----------------------------------------------------------------
* Determine if polygon A overlaps polygon B by determining if
* their bounding boxes overlap.
*
* XXX ought to do a more correct check!
* Determine if polygon A overlaps polygon B
*-----------------------------------------------------------------*/
Datum
poly_overlap(PG_FUNCTION_ARGS)
@ -3754,7 +3767,54 @@ poly_overlap(PG_FUNCTION_ARGS)
POLYGON *polyb = PG_GETARG_POLYGON_P(1);
bool result;
result = box_ov(&polya->boundbox, &polyb->boundbox);
/* Quick check by bounding box */
result = (polya->npts > 0 && polyb->npts > 0 &&
box_ov(&polya->boundbox, &polyb->boundbox)) ? true : false;
/*
* Brute-force algorithm - try to find intersected edges,
* if so then polygons are overlapped else check is one
* polygon inside other or not by testing single point
* of them.
*/
if (result)
{
int ia, ib;
LSEG sa, sb;
/* Init first of polya's edge with last point */
sa.p[0] = polya->p[polya->npts - 1];
result = false;
for(ia=0; ia<polya->npts && result == false; ia++)
{
/* Second point of polya's edge is a current one */
sa.p[1] = polya->p[ia];
/* Init first of polyb's edge with last point */
sb.p[0] = polyb->p[polyb->npts - 1];
for(ib=0; ib<polyb->npts && result == false; ib++)
{
sb.p[1] = polyb->p[ib];
result = lseg_intersect_internal(&sa, &sb);
sb.p[0] = sb.p[1];
}
/*
* move current endpoint to the first point
* of next edge
*/
sa.p[0] = sa.p[1];
}
if (result==false)
{
result = ( point_inside(polya->p, polyb->npts, polyb->p)
||
point_inside(polyb->p, polya->npts, polya->p) );
}
}
/*
* Avoid leaking memory for toasted inputs ... needed for rtree indexes
@ -3765,6 +3825,119 @@ poly_overlap(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(result);
}
/*
* Tests special kind of segment for in/out of polygon.
* Special kind means:
* - point a should be on segment s
* - segment (a,b) should not be contained by s
* Returns true if:
* - segment (a,b) is collinear to s and (a,b) is in polygon
* - segment (a,b) s not collinear to s. Note: that doesn't
* mean that segment is in polygon!
*/
static bool
touched_lseg_inside_poly(Point *a, Point *b, LSEG *s, POLYGON *poly, int start)
{
/* point a is on s, b is not */
LSEG t;
t.p[0] = *a;
t.p[1] = *b;
#define POINTEQ(pt1, pt2) (FPeq((pt1)->x, (pt2)->x) && FPeq((pt1)->y, (pt2)->y))
if ( POINTEQ(a, s->p) )
{
if ( on_ps_internal(s->p+1, &t) )
return lseg_inside_poly(b, s->p+1, poly, start);
}
else if (POINTEQ(a, s->p+1))
{
if ( on_ps_internal(s->p, &t) )
return lseg_inside_poly(b, s->p, poly, start);
}
else if ( on_ps_internal(s->p, &t) )
{
return lseg_inside_poly(b, s->p, poly, start);
}
else if ( on_ps_internal(s->p+1, &t) )
{
return lseg_inside_poly(b, s->p+1, poly, start);
}
return true; /* may be not true, but that will check later */
}
/*
* Returns true if segment (a,b) is in polygon, option
* start is used for optimization - function checks
* polygon's edges started from start
*/
static bool
lseg_inside_poly(Point *a, Point *b, POLYGON *poly, int start)
{
LSEG s,
t;
int i;
bool res = true,
intersection = false;
t.p[0] = *a;
t.p[1] = *b;
s.p[0] = poly->p[( start == 0) ? (poly->npts - 1) : (start - 1)];
for(i=start; i<poly->npts && res == true; i++)
{
Point *interpt;
s.p[1] = poly->p[i];
if ( on_ps_internal(t.p, &s) )
{
if ( on_ps_internal(t.p+1, &s) )
return true; /* t is contained by s */
/* Y-cross */
res = touched_lseg_inside_poly(t.p, t.p+1, &s, poly, i+1);
}
else if ( on_ps_internal(t.p+1, &s) )
{
/* Y-cross */
res = touched_lseg_inside_poly(t.p+1, t.p, &s, poly, i+1);
}
else if ( (interpt = lseg_interpt_internal(&t, &s)) != NULL )
{
/*
* segments are X-crossing, go to check each subsegment
*/
intersection = true;
res = lseg_inside_poly(t.p, interpt, poly, i+1);
if (res)
res = lseg_inside_poly(t.p+1, interpt, poly, i+1);
pfree(interpt);
}
s.p[0] = s.p[1];
}
if (res && !intersection)
{
Point p;
/*
* if X-intersection wasn't found then check central point
* of tested segment. In opposite case we already check all
* subsegments
*/
p.x = (t.p[0].x + t.p[1].x) / 2.0;
p.y = (t.p[0].y + t.p[1].y) / 2.0;
res = point_inside(&p, poly->npts, poly->p);
}
return res;
}
/*-----------------------------------------------------------------
* Determine if polygon A contains polygon B.
@ -3775,49 +3948,30 @@ poly_contain(PG_FUNCTION_ARGS)
POLYGON *polya = PG_GETARG_POLYGON_P(0);
POLYGON *polyb = PG_GETARG_POLYGON_P(1);
bool result;
int i;
/*
* Quick check to see if bounding box is contained.
*/
if (DatumGetBool(DirectFunctionCall2(box_contain,
BoxPGetDatum(&polya->boundbox),
BoxPGetDatum(&polyb->boundbox))))
if (polya->npts > 0 && polyb->npts > 0 &&
DatumGetBool(DirectFunctionCall2(box_contain,
BoxPGetDatum(&polya->boundbox),
BoxPGetDatum(&polyb->boundbox))))
{
result = true; /* assume true for now */
for (i = 0; i < polyb->npts; i++)
int i;
LSEG s;
s.p[0] = polyb->p[polyb->npts - 1];
result = true;
for(i=0; i<polyb->npts && result == true; i++)
{
if (point_inside(&(polyb->p[i]), polya->npts, &(polya->p[0])) == 0)
{
#ifdef GEODEBUG
printf("poly_contain- point (%f,%f) not in polygon\n", polyb->p[i].x, polyb->p[i].y);
#endif
result = false;
break;
}
}
if (result)
{
for (i = 0; i < polya->npts; i++)
{
if (point_inside(&(polya->p[i]), polyb->npts, &(polyb->p[0])) == 1)
{
#ifdef GEODEBUG
printf("poly_contain- point (%f,%f) in polygon\n", polya->p[i].x, polya->p[i].y);
#endif
result = false;
break;
}
}
s.p[1] = polyb->p[i];
result = lseg_inside_poly(s.p, s.p+1, polya, 0);
s.p[0] = s.p[1];
}
}
else
{
#ifdef GEODEBUG
printf("poly_contain- bound box ((%f,%f),(%f,%f)) not inside ((%f,%f),(%f,%f))\n",
polyb->boundbox.low.x, polyb->boundbox.low.y, polyb->boundbox.high.x, polyb->boundbox.high.y,
polya->boundbox.low.x, polya->boundbox.low.y, polya->boundbox.high.x, polya->boundbox.high.y);
#endif
result = false;
}

2
src/test/regress/expected/create_index.out
View File

@ -53,6 +53,8 @@ CREATE INDEX gpolygonind ON polygon_tbl USING gist (f1);
CREATE INDEX gcircleind ON circle_tbl USING gist (f1);
CREATE TEMP TABLE gpolygon_tbl AS
SELECT polygon(home_base) AS f1 FROM slow_emp4000;
INSERT INTO gpolygon_tbl VALUES ( '(1000,0,0,1000)' );
INSERT INTO gpolygon_tbl VALUES ( '(0,1000,1000,1000)' );
CREATE TEMP TABLE gcircle_tbl AS
SELECT circle(home_base) AS f1 FROM slow_emp4000;
CREATE INDEX ggpolygonind ON gpolygon_tbl USING gist (f1);

84
src/test/regress/expected/polygon.out
View File

@ -180,6 +180,59 @@ SELECT polygon '(2.0,0.0),(2.0,4.0),(0.0,0.0)' @> polygon '(3.0,1.0),(3.0,3.0),(
f
(1 row)
-- +------------------------+
-- | *---* 1
-- | + | |
-- | 2 *---*
-- +------------------------+
-- 3
-- endpoints '+' is ofr one polygon, '*' - for another
-- Edges 1-2, 2-3 are not shown on picture
SELECT '((0,4),(6,4),(1,2),(6,0),(0,0))'::polygon @> '((2,1),(2,3),(3,3),(3,1))'::polygon AS "false";
false
-------
f
(1 row)
-- +-----------+
-- | *---* /
-- | | |/
-- | | +
-- | | |\
-- | *---* \
-- +-----------+
SELECT '((0,4),(6,4),(3,2),(6,0),(0,0))'::polygon @> '((2,1),(2,3),(3,3),(3,1))'::polygon AS "true";
true
------
t
(1 row)
-- +-----------------+
-- | |
-- | +---*---*-----+
-- | | | |
-- | +---*---*-----+
-- | |
-- +-----------------+
SELECT '((1,1),(1,4),(5,4),(5,3),(2,3),(2,2),(5,2),(5,1))'::polygon @> '((3,2),(3,3),(4,3),(4,2))'::polygon AS "false";
false
-------
f
(1 row)
-- +---------+
-- | |
-- | *----*
-- | | |
-- | *----*
-- | |
-- +---------+
SELECT '((0,0),(0,3),(3,3),(3,0))'::polygon @> '((2,1),(2,2),(3,2),(3,1))'::polygon AS "true";
true
------
t
(1 row)
-- same
SELECT polygon '(2.0,0.0),(2.0,4.0),(0.0,0.0)' ~= polygon '(3.0,1.0),(3.0,3.0),(1.0,0.0)' AS false;
false
@ -194,3 +247,34 @@ SELECT polygon '(2.0,0.0),(2.0,4.0),(0.0,0.0)' && polygon '(3.0,1.0),(3.0,3.0),(
t
(1 row)
-- +--------------------+
-- | *---* 1
-- | + | |
-- | 2 *---*
-- +--------------------+
-- 3
-- Edges 1-2, 2-3 are not shown on picture
SELECT '((0,4),(6,4),(1,2),(6,0),(0,0))'::polygon && '((2,1),(2,3),(3,3),(3,1))'::polygon AS "true";
true
------
t
(1 row)
-- +--+ *--*
-- | | | |
-- | | *--*
-- | +----+
-- | |
-- +-------+
SELECT '((1,4),(1,1),(4,1),(4,2),(2,2),(2,4),(1,4))'::polygon && '((3,3),(4,3),(4,4),(3,4),(3,3))'::polygon AS "false";
false
-------
f
(1 row)
SELECT '((200,800),(800,800),(800,200),(200,200))' && '(1000,1000,0,0)'::polygon AS "true";
true
------
t
(1 row)

2
src/test/regress/sql/create_index.sql
View File

@ -78,6 +78,8 @@ CREATE INDEX gcircleind ON circle_tbl USING gist (f1);
CREATE TEMP TABLE gpolygon_tbl AS
SELECT polygon(home_base) AS f1 FROM slow_emp4000;
INSERT INTO gpolygon_tbl VALUES ( '(1000,0,0,1000)' );
INSERT INTO gpolygon_tbl VALUES ( '(0,1000,1000,1000)' );
CREATE TEMP TABLE gcircle_tbl AS
SELECT circle(home_base) AS f1 FROM slow_emp4000;

55
src/test/regress/sql/polygon.sql
View File

@ -111,9 +111,64 @@ SELECT polygon '(2.0,0.0),(2.0,4.0),(0.0,0.0)' <@ polygon '(3.0,1.0),(3.0,3.0),(
-- contains
SELECT polygon '(2.0,0.0),(2.0,4.0),(0.0,0.0)' @> polygon '(3.0,1.0),(3.0,3.0),(1.0,0.0)' AS false;
-- +------------------------+
-- | *---* 1
-- | + | |
-- | 2 *---*
-- +------------------------+
-- 3
-- endpoints '+' is ofr one polygon, '*' - for another
-- Edges 1-2, 2-3 are not shown on picture
SELECT '((0,4),(6,4),(1,2),(6,0),(0,0))'::polygon @> '((2,1),(2,3),(3,3),(3,1))'::polygon AS "false";
-- +-----------+
-- | *---* /
-- | | |/
-- | | +
-- | | |\
-- | *---* \
-- +-----------+
SELECT '((0,4),(6,4),(3,2),(6,0),(0,0))'::polygon @> '((2,1),(2,3),(3,3),(3,1))'::polygon AS "true";
-- +-----------------+
-- | |
-- | +---*---*-----+
-- | | | |
-- | +---*---*-----+
-- | |
-- +-----------------+
SELECT '((1,1),(1,4),(5,4),(5,3),(2,3),(2,2),(5,2),(5,1))'::polygon @> '((3,2),(3,3),(4,3),(4,2))'::polygon AS "false";
-- +---------+
-- | |
-- | *----*
-- | | |
-- | *----*
-- | |
-- +---------+
SELECT '((0,0),(0,3),(3,3),(3,0))'::polygon @> '((2,1),(2,2),(3,2),(3,1))'::polygon AS "true";
-- same
SELECT polygon '(2.0,0.0),(2.0,4.0),(0.0,0.0)' ~= polygon '(3.0,1.0),(3.0,3.0),(1.0,0.0)' AS false;
-- overlap
SELECT polygon '(2.0,0.0),(2.0,4.0),(0.0,0.0)' && polygon '(3.0,1.0),(3.0,3.0),(1.0,0.0)' AS true;
-- +--------------------+
-- | *---* 1
-- | + | |
-- | 2 *---*
-- +--------------------+
-- 3
-- Edges 1-2, 2-3 are not shown on picture
SELECT '((0,4),(6,4),(1,2),(6,0),(0,0))'::polygon && '((2,1),(2,3),(3,3),(3,1))'::polygon AS "true";
-- +--+ *--*
-- | | | |
-- | | *--*
-- | +----+
-- | |
-- +-------+
SELECT '((1,4),(1,1),(4,1),(4,2),(2,2),(2,4),(1,4))'::polygon && '((3,3),(4,3),(4,4),(3,4),(3,3))'::polygon AS "false";
SELECT '((200,800),(800,800),(800,200),(200,200))' && '(1000,1000,0,0)'::polygon AS "true";