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Add point <-> polygon distance operator.

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Alexander Korotkov, reviewed by Emre Hasegeli.
This commit is contained in:
Heikki Linnakangas
2014-12-15 17:02:49 +02:00
parent ee3bec5e22
commit 4520ba6769
6 changed files with 82 additions and 16 deletions
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76
src/backend/utils/adt/geo_ops.c
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@ -73,6 +73,7 @@ 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);
static double dist_ppoly_internal(Point *pt, POLYGON *poly);
/*
@ -2415,6 +2416,9 @@ lseg_interpt(PG_FUNCTION_ARGS)
* Minimum distance from one object to another.
*-------------------------------------------------------------------*/
/*
* Distance from a point to a line
*/
Datum
dist_pl(PG_FUNCTION_ARGS)
{
@ -2431,6 +2435,9 @@ dist_pl_internal(Point *pt, LINE *line)
HYPOT(line->A, line->B));
}
/*
* Distance from a point to a lseg
*/
Datum
dist_ps(PG_FUNCTION_ARGS)
{
@ -2494,7 +2501,7 @@ dist_ps_internal(Point *pt, LSEG *lseg)
}
/*
** Distance from a point to a path
* Distance from a point to a path
*/
Datum
dist_ppath(PG_FUNCTION_ARGS)
@ -2550,6 +2557,9 @@ dist_ppath(PG_FUNCTION_ARGS)
PG_RETURN_FLOAT8(result);
}
/*
* Distance from a point to a box
*/
Datum
dist_pb(PG_FUNCTION_ARGS)
{
@ -2566,7 +2576,9 @@ dist_pb(PG_FUNCTION_ARGS)
PG_RETURN_FLOAT8(result);
}
/*
* Distance from a lseg to a line
*/
Datum
dist_sl(PG_FUNCTION_ARGS)
{
@ -2589,7 +2601,9 @@ dist_sl(PG_FUNCTION_ARGS)
PG_RETURN_FLOAT8(result);
}
/*
* Distance from a lseg to a box
*/
Datum
dist_sb(PG_FUNCTION_ARGS)
{
@ -2608,7 +2622,9 @@ dist_sb(PG_FUNCTION_ARGS)
PG_RETURN_DATUM(result);
}
/*
* Distance from a line to a box
*/
Datum
dist_lb(PG_FUNCTION_ARGS)
{
@ -2625,21 +2641,53 @@ dist_lb(PG_FUNCTION_ARGS)
PG_RETURN_NULL();
}
/*
* Distance from a circle to a polygon
*/
Datum
dist_cpoly(PG_FUNCTION_ARGS)
{
CIRCLE *circle = PG_GETARG_CIRCLE_P(0);
POLYGON *poly = PG_GETARG_POLYGON_P(1);
float8 result;
/* calculate distance to center, and subtract radius */
result = dist_ppoly_internal(&circle->center, poly);
result -= circle->radius;
if (result < 0)
result = 0;
PG_RETURN_FLOAT8(result);
}
/*
* Distance from a point to a polygon
*/
Datum
dist_ppoly(PG_FUNCTION_ARGS)
{
Point *point = PG_GETARG_POINT_P(0);
POLYGON *poly = PG_GETARG_POLYGON_P(1);
float8 result;
result = dist_ppoly_internal(point, poly);
PG_RETURN_FLOAT8(result);
}
static double
dist_ppoly_internal(Point *pt, POLYGON *poly)
{
float8 result;
float8 d;
int i;
LSEG seg;
if (point_inside(&(circle->center), poly->npts, poly->p) != 0)
if (point_inside(pt, poly->npts, poly->p) != 0)
{
#ifdef GEODEBUG
printf("dist_cpoly- center inside of polygon\n");
printf("dist_ppoly_internal- point inside of polygon\n");
#endif
PG_RETURN_FLOAT8(0.0);
}
@ -2649,9 +2697,9 @@ dist_cpoly(PG_FUNCTION_ARGS)
seg.p[0].y = poly->p[0].y;
seg.p[1].x = poly->p[poly->npts - 1].x;
seg.p[1].y = poly->p[poly->npts - 1].y;
result = dist_ps_internal(&circle->center, &seg);
result = dist_ps_internal(pt, &seg);
#ifdef GEODEBUG
printf("dist_cpoly- segment 0/n distance is %f\n", result);
printf("dist_ppoly_internal- segment 0/n distance is %f\n", result);
#endif
/* check distances for other segments */
@ -2661,19 +2709,15 @@ dist_cpoly(PG_FUNCTION_ARGS)
seg.p[0].y = poly->p[i].y;
seg.p[1].x = poly->p[i + 1].x;
seg.p[1].y = poly->p[i + 1].y;
d = dist_ps_internal(&circle->center, &seg);
d = dist_ps_internal(pt, &seg);
#ifdef GEODEBUG
printf("dist_cpoly- segment %d distance is %f\n", (i + 1), d);
printf("dist_ppoly_internal- segment %d distance is %f\n", (i + 1), d);
#endif
if (d < result)
result = d;
}
result -= circle->radius;
if (result < 0)
result = 0;
PG_RETURN_FLOAT8(result);
return result;
}