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lwlinearreferencing.c
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/**********************************************************************
*
* PostGIS - Spatial Types for PostgreSQL
* http://postgis.net
*
* PostGIS is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* PostGIS is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with PostGIS. If not, see <http://www.gnu.org/licenses/>.
*
**********************************************************************
*
* Copyright (C) 2015 Sandro Santilli <strk@kbt.io>
* Copyright (C) 2011 Paul Ramsey
*
**********************************************************************/
#include "liblwgeom_internal.h"
#include "lwgeom_log.h"
#include "measures3d.h"
static int
segment_locate_along(const POINT4D *p1, const POINT4D *p2, double m, double offset, POINT4D *pn)
{
double m1 = p1->m;
double m2 = p2->m;
double mprop;
/* M is out of range, no new point generated. */
if ( (m < FP_MIN(m1,m2)) || (m > FP_MAX(m1,m2)) )
{
return LW_FALSE;
}
if( m1 == m2 )
{
/* Degenerate case: same M on both points.
If they are the same point we just return one of them. */
if ( p4d_same(p1,p2) )
{
*pn = *p1;
return LW_TRUE;
}
/* If the points are different we split the difference */
mprop = 0.5;
}
else
{
mprop = (m - m1) / (m2 - m1);
}
/* M is in range, new point to be generated. */
pn->x = p1->x + (p2->x - p1->x) * mprop;
pn->y = p1->y + (p2->y - p1->y) * mprop;
pn->z = p1->z + (p2->z - p1->z) * mprop;
pn->m = m;
/* Offset to the left or right, if necessary. */
if ( offset != 0.0 )
{
double theta = atan2(p2->y - p1->y, p2->x - p1->x);
pn->x -= sin(theta) * offset;
pn->y += cos(theta) * offset;
}
return LW_TRUE;
}
static POINTARRAY*
ptarray_locate_along(const POINTARRAY *pa, double m, double offset)
{
uint32_t i;
POINT4D p1, p2, pn;
POINTARRAY *dpa = NULL;
/* Can't do anything with degenerate point arrays */
if ( ! pa || pa->npoints < 2 ) return NULL;
/* Walk through each segment in the point array */
for ( i = 1; i < pa->npoints; i++ )
{
getPoint4d_p(pa, i-1, &p1);
getPoint4d_p(pa, i, &p2);
/* No derived point? Move to next segment. */
if ( segment_locate_along(&p1, &p2, m, offset, &pn) == LW_FALSE )
continue;
/* No pointarray, make a fresh one */
if ( dpa == NULL )
dpa = ptarray_construct_empty(ptarray_has_z(pa), ptarray_has_m(pa), 8);
/* Add our new point to the array */
ptarray_append_point(dpa, &pn, 0);
}
return dpa;
}
static LWMPOINT*
lwline_locate_along(const LWLINE *lwline, double m, double offset)
{
POINTARRAY *opa = NULL;
LWMPOINT *mp = NULL;
LWGEOM *lwg = lwline_as_lwgeom(lwline);
int hasz, hasm, srid;
/* Return degenerates upwards */
if ( ! lwline ) return NULL;
/* Create empty return shell */
srid = lwgeom_get_srid(lwg);
hasz = lwgeom_has_z(lwg);
hasm = lwgeom_has_m(lwg);
if ( hasm )
{
/* Find points along */
opa = ptarray_locate_along(lwline->points, m, offset);
}
else
{
LWLINE *lwline_measured = lwline_measured_from_lwline(lwline, 0.0, 1.0);
opa = ptarray_locate_along(lwline_measured->points, m, offset);
lwline_free(lwline_measured);
}
/* Return NULL as EMPTY */
if ( ! opa )
return lwmpoint_construct_empty(srid, hasz, hasm);
/* Convert pointarray into a multipoint */
mp = lwmpoint_construct(srid, opa);
ptarray_free(opa);
return mp;
}
static LWMPOINT*
lwmline_locate_along(const LWMLINE *lwmline, double m, double offset)
{
LWMPOINT *lwmpoint = NULL;
LWGEOM *lwg = lwmline_as_lwgeom(lwmline);
uint32_t i, j;
/* Return degenerates upwards */
if ( (!lwmline) || (lwmline->ngeoms < 1) ) return NULL;
/* Construct return */
lwmpoint = lwmpoint_construct_empty(lwgeom_get_srid(lwg), lwgeom_has_z(lwg), lwgeom_has_m(lwg));
/* Locate along each sub-line */
for ( i = 0; i < lwmline->ngeoms; i++ )
{
LWMPOINT *along = lwline_locate_along(lwmline->geoms[i], m, offset);
if ( along )
{
if ( ! lwgeom_is_empty((LWGEOM*)along) )
{
for ( j = 0; j < along->ngeoms; j++ )
{
lwmpoint_add_lwpoint(lwmpoint, along->geoms[j]);
}
}
/* Free the containing geometry, but leave the sub-geometries around */
along->ngeoms = 0;
lwmpoint_free(along);
}
}
return lwmpoint;
}
static LWMPOINT*
lwpoint_locate_along(const LWPOINT *lwpoint, double m, __attribute__((__unused__)) double offset)
{
double point_m = lwpoint_get_m(lwpoint);
LWGEOM *lwg = lwpoint_as_lwgeom(lwpoint);
LWMPOINT *r = lwmpoint_construct_empty(lwgeom_get_srid(lwg), lwgeom_has_z(lwg), lwgeom_has_m(lwg));
if ( FP_EQUALS(m, point_m) )
{
lwmpoint_add_lwpoint(r, lwpoint_clone(lwpoint));
}
return r;
}
static LWMPOINT*
lwmpoint_locate_along(const LWMPOINT *lwin, double m, __attribute__((__unused__)) double offset)
{
LWGEOM *lwg = lwmpoint_as_lwgeom(lwin);
LWMPOINT *lwout = NULL;
uint32_t i;
/* Construct return */
lwout = lwmpoint_construct_empty(lwgeom_get_srid(lwg), lwgeom_has_z(lwg), lwgeom_has_m(lwg));
for ( i = 0; i < lwin->ngeoms; i++ )
{
double point_m = lwpoint_get_m(lwin->geoms[i]);
if ( FP_EQUALS(m, point_m) )
{
lwmpoint_add_lwpoint(lwout, lwpoint_clone(lwin->geoms[i]));
}
}
return lwout;
}
LWGEOM*
lwgeom_locate_along(const LWGEOM *lwin, double m, double offset)
{
if ( ! lwin ) return NULL;
if ( ! lwgeom_has_m(lwin) )
lwerror("Input geometry does not have a measure dimension");
switch (lwin->type)
{
case POINTTYPE:
return (LWGEOM*)lwpoint_locate_along((LWPOINT*)lwin, m, offset);
case MULTIPOINTTYPE:
return (LWGEOM*)lwmpoint_locate_along((LWMPOINT*)lwin, m, offset);
case LINETYPE:
return (LWGEOM*)lwline_locate_along((LWLINE*)lwin, m, offset);
case MULTILINETYPE:
return (LWGEOM*)lwmline_locate_along((LWMLINE*)lwin, m, offset);
/* Only line types supported right now */
/* TO DO: CurveString, CompoundCurve, MultiCurve */
/* TO DO: Point, MultiPoint */
default:
lwerror("Only linear geometries are supported, %s provided.",lwtype_name(lwin->type));
return NULL;
}
return NULL;
}
/**
* Given a POINT4D and an ordinate number, return
* the value of the ordinate.
* @param p input point
* @param ordinate number (1=x, 2=y, 3=z, 4=m)
* @return d value at that ordinate
*/
double lwpoint_get_ordinate(const POINT4D *p, char ordinate)
{
if ( ! p )
{
lwerror("Null input geometry.");
return 0.0;
}
if ( ! ( ordinate == 'X' || ordinate == 'Y' || ordinate == 'Z' || ordinate == 'M' ) )
{
lwerror("Cannot extract %c ordinate.", ordinate);
return 0.0;
}
if ( ordinate == 'X' )
return p->x;
if ( ordinate == 'Y' )
return p->y;
if ( ordinate == 'Z' )
return p->z;
if ( ordinate == 'M' )
return p->m;
/* X */
return p->x;
}
/**
* Given a point, ordinate number and value, set that ordinate on the
* point.
*/
void lwpoint_set_ordinate(POINT4D *p, char ordinate, double value)
{
if ( ! p )
{
lwerror("Null input geometry.");
return;
}
if ( ! ( ordinate == 'X' || ordinate == 'Y' || ordinate == 'Z' || ordinate == 'M' ) )
{
lwerror("Cannot set %c ordinate.", ordinate);
return;
}
LWDEBUGF(4, " setting ordinate %c to %g", ordinate, value);
switch ( ordinate )
{
case 'X':
p->x = value;
return;
case 'Y':
p->y = value;
return;
case 'Z':
p->z = value;
return;
case 'M':
p->m = value;
return;
}
}
/**
* Given two points, a dimensionality, an ordinate, and an interpolation value
* generate a new point that is proportionally between the input points,
* using the values in the provided dimension as the scaling factors.
*/
int point_interpolate(const POINT4D *p1, const POINT4D *p2, POINT4D *p, int hasz, int hasm, char ordinate, double interpolation_value)
{
static char* dims = "XYZM";
double p1_value = lwpoint_get_ordinate(p1, ordinate);
double p2_value = lwpoint_get_ordinate(p2, ordinate);
double proportion;
int i = 0;
if ( ! ( ordinate == 'X' || ordinate == 'Y' || ordinate == 'Z' || ordinate == 'M' ) )
{
lwerror("Cannot set %c ordinate.", ordinate);
return 0;
}
if ( FP_MIN(p1_value, p2_value) > interpolation_value ||
FP_MAX(p1_value, p2_value) < interpolation_value )
{
lwerror("Cannot interpolate to a value (%g) not between the input points (%g, %g).", interpolation_value, p1_value, p2_value);
return 0;
}
proportion = fabs((interpolation_value - p1_value) / (p2_value - p1_value));
for ( i = 0; i < 4; i++ )
{
double newordinate = 0.0;
if ( dims[i] == 'Z' && ! hasz ) continue;
if ( dims[i] == 'M' && ! hasm ) continue;
p1_value = lwpoint_get_ordinate(p1, dims[i]);
p2_value = lwpoint_get_ordinate(p2, dims[i]);
newordinate = p1_value + proportion * (p2_value - p1_value);
lwpoint_set_ordinate(p, dims[i], newordinate);
LWDEBUGF(4, " clip ordinate(%c) p1_value(%g) p2_value(%g) proportion(%g) newordinate(%g) ", dims[i], p1_value, p2_value, proportion, newordinate );
}
return 1;
}
/**
* Clip an input POINT between two values, on any ordinate input.
*/
LWCOLLECTION*
lwpoint_clip_to_ordinate_range(const LWPOINT *point, char ordinate, double from, double to)
{
LWCOLLECTION *lwgeom_out = NULL;
char hasz, hasm;
POINT4D p4d;
double ordinate_value;
/* Nothing to do with NULL */
if ( ! point )
lwerror("Null input geometry.");
/* Ensure 'from' is less than 'to'. */
if ( to < from )
{
double t = from;
from = to;
to = t;
}
/* Read Z/M info */
hasz = lwgeom_has_z(lwpoint_as_lwgeom(point));
hasm = lwgeom_has_m(lwpoint_as_lwgeom(point));
/* Prepare return object */
lwgeom_out = lwcollection_construct_empty(MULTIPOINTTYPE, point->srid, hasz, hasm);
/* Test if ordinate is in range */
lwpoint_getPoint4d_p(point, &p4d);
ordinate_value = lwpoint_get_ordinate(&p4d, ordinate);
if ( from <= ordinate_value && to >= ordinate_value )
{
LWPOINT *lwp = lwpoint_clone(point);
lwcollection_add_lwgeom(lwgeom_out, lwpoint_as_lwgeom(lwp));
}
/* Set the bbox, if necessary */
if ( lwgeom_out->bbox )
{
lwgeom_refresh_bbox((LWGEOM*)lwgeom_out);
}
return lwgeom_out;
}
/**
* Clip an input MULTIPOINT between two values, on any ordinate input.
*/
LWCOLLECTION*
lwmpoint_clip_to_ordinate_range(const LWMPOINT *mpoint, char ordinate, double from, double to)
{
LWCOLLECTION *lwgeom_out = NULL;
char hasz, hasm;
uint32_t i;
/* Nothing to do with NULL */
if ( ! mpoint )
lwerror("Null input geometry.");
/* Ensure 'from' is less than 'to'. */
if ( to < from )
{
double t = from;
from = to;
to = t;
}
/* Read Z/M info */
hasz = lwgeom_has_z(lwmpoint_as_lwgeom(mpoint));
hasm = lwgeom_has_m(lwmpoint_as_lwgeom(mpoint));
/* Prepare return object */
lwgeom_out = lwcollection_construct_empty(MULTIPOINTTYPE, mpoint->srid, hasz, hasm);
/* For each point, is its ordinate value between from and to? */
for ( i = 0; i < mpoint->ngeoms; i ++ )
{
POINT4D p4d;
double ordinate_value;
lwpoint_getPoint4d_p(mpoint->geoms[i], &p4d);
ordinate_value = lwpoint_get_ordinate(&p4d, ordinate);
if ( from <= ordinate_value && to >= ordinate_value )
{
LWPOINT *lwp = lwpoint_clone(mpoint->geoms[i]);
lwcollection_add_lwgeom(lwgeom_out, lwpoint_as_lwgeom(lwp));
}
}
/* Set the bbox, if necessary */
if ( lwgeom_out->bbox )
{
lwgeom_refresh_bbox((LWGEOM*)lwgeom_out);
}
return lwgeom_out;
}
/**
* Clip an input MULTILINESTRING between two values, on any ordinate input.
*/
LWCOLLECTION*
lwmline_clip_to_ordinate_range(const LWMLINE *mline, char ordinate, double from, double to)
{
LWCOLLECTION *lwgeom_out = NULL;
if ( ! mline )
{
lwerror("Null input geometry.");
return NULL;
}
if ( mline->ngeoms == 1)
{
lwgeom_out = lwline_clip_to_ordinate_range(mline->geoms[0], ordinate, from, to);
}
else
{
LWCOLLECTION *col;
char hasz = lwgeom_has_z(lwmline_as_lwgeom(mline));
char hasm = lwgeom_has_m(lwmline_as_lwgeom(mline));
uint32_t i, j;
char homogeneous = 1;
size_t geoms_size = 0;
lwgeom_out = lwcollection_construct_empty(MULTILINETYPE, mline->srid, hasz, hasm);
FLAGS_SET_Z(lwgeom_out->flags, hasz);
FLAGS_SET_M(lwgeom_out->flags, hasm);
for ( i = 0; i < mline->ngeoms; i ++ )
{
col = lwline_clip_to_ordinate_range(mline->geoms[i], ordinate, from, to);
if ( col )
{
/* Something was left after the clip. */
if ( lwgeom_out->ngeoms + col->ngeoms > geoms_size )
{
geoms_size += 16;
if ( lwgeom_out->geoms )
{
lwgeom_out->geoms = lwrealloc(lwgeom_out->geoms, geoms_size * sizeof(LWGEOM*));
}
else
{
lwgeom_out->geoms = lwalloc(geoms_size * sizeof(LWGEOM*));
}
}
for ( j = 0; j < col->ngeoms; j++ )
{
lwgeom_out->geoms[lwgeom_out->ngeoms] = col->geoms[j];
lwgeom_out->ngeoms++;
}
if ( col->type != mline->type )
{
homogeneous = 0;
}
/* Shallow free the struct, leaving the geoms behind. */
if ( col->bbox ) lwfree(col->bbox);
lwfree(col->geoms);
lwfree(col);
}
}
if ( lwgeom_out->bbox )
{
lwgeom_refresh_bbox((LWGEOM*)lwgeom_out);
}
if ( ! homogeneous )
{
lwgeom_out->type = COLLECTIONTYPE;
}
}
return lwgeom_out;
}
/**
* Take in a LINESTRING and return a MULTILINESTRING of those portions of the
* LINESTRING between the from/to range for the specified ordinate (XYZM)
*/
LWCOLLECTION*
lwline_clip_to_ordinate_range(const LWLINE *line, char ordinate, double from, double to)
{
POINTARRAY *pa_in = NULL;
LWCOLLECTION *lwgeom_out = NULL;
POINTARRAY *dp = NULL;
uint32_t i;
int added_last_point = 0;
POINT4D *p = NULL, *q = NULL, *r = NULL;
double ordinate_value_p = 0.0, ordinate_value_q = 0.0;
char hasz, hasm;
char dims;
/* Null input, nothing we can do. */
if ( ! line )
{
lwerror("Null input geometry.");
return NULL;
}
hasz = lwgeom_has_z(lwline_as_lwgeom(line));
hasm = lwgeom_has_m(lwline_as_lwgeom(line));
dims = FLAGS_NDIMS(line->flags);
/* Ensure 'from' is less than 'to'. */
if ( to < from )
{
double t = from;
from = to;
to = t;
}
LWDEBUGF(4, "from = %g, to = %g, ordinate = %c", from, to, ordinate);
LWDEBUGF(4, "%s", lwgeom_to_ewkt((LWGEOM*)line));
/* Asking for an ordinate we don't have. Error. */
if ( (ordinate == 'Z' && ! hasz) || (ordinate == 'M' && ! hasm) )
{
lwerror("Cannot clip on ordinate %d in a %d-d geometry.", ordinate, dims);
return NULL;
}
/* Prepare our working point objects. */
p = lwalloc(sizeof(POINT4D));
q = lwalloc(sizeof(POINT4D));
r = lwalloc(sizeof(POINT4D));
/* Construct a collection to hold our outputs. */
lwgeom_out = lwcollection_construct_empty(MULTILINETYPE, line->srid, hasz, hasm);
/* Get our input point array */
pa_in = line->points;
for ( i = 0; i < pa_in->npoints; i++ )
{
LWDEBUGF(4, "Point #%d", i);
LWDEBUGF(4, "added_last_point %d", added_last_point);
if ( i > 0 )
{
*q = *p;
ordinate_value_q = ordinate_value_p;
}
getPoint4d_p(pa_in, i, p);
ordinate_value_p = lwpoint_get_ordinate(p, ordinate);
LWDEBUGF(4, " ordinate_value_p %g (current)", ordinate_value_p);
LWDEBUGF(4, " ordinate_value_q %g (previous)", ordinate_value_q);
/* Is this point inside the ordinate range? Yes. */
if ( ordinate_value_p >= from && ordinate_value_p <= to )
{
LWDEBUGF(4, " inside ordinate range (%g, %g)", from, to);
if ( ! added_last_point )
{
LWDEBUG(4," new ptarray required");
/* We didn't add the previous point, so this is a new segment.
* Make a new point array. */
dp = ptarray_construct_empty(hasz, hasm, 32);
/* We're transiting into the range so add an interpolated
* point at the range boundary.
* If we're on a boundary and crossing from the far side,
* we also need an interpolated point. */
if ( i > 0 && ( /* Don't try to interpolate if this is the first point */
( ordinate_value_p > from && ordinate_value_p < to ) || /* Inside */
( ordinate_value_p == from && ordinate_value_q > to ) || /* Hopping from above */
( ordinate_value_p == to && ordinate_value_q < from ) ) ) /* Hopping from below */
{
double interpolation_value;
(ordinate_value_q > to) ? (interpolation_value = to) : (interpolation_value = from);
point_interpolate(q, p, r, hasz, hasm, ordinate, interpolation_value);
ptarray_append_point(dp, r, LW_FALSE);
LWDEBUGF(4, "[0] interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
}
}
/* Add the current vertex to the point array. */
ptarray_append_point(dp, p, LW_FALSE);
if ( ordinate_value_p == from || ordinate_value_p == to )
{
added_last_point = 2; /* Added on boundary. */
}
else
{
added_last_point = 1; /* Added inside range. */
}
}
/* Is this point inside the ordinate range? No. */
else
{
LWDEBUGF(4, " added_last_point (%d)", added_last_point);
if ( added_last_point == 1 )
{
/* We're transiting out of the range, so add an interpolated point
* to the point array at the range boundary. */
double interpolation_value;
(ordinate_value_p > to) ? (interpolation_value = to) : (interpolation_value = from);
point_interpolate(q, p, r, hasz, hasm, ordinate, interpolation_value);
ptarray_append_point(dp, r, LW_FALSE);
LWDEBUGF(4, " [1] interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
}
else if ( added_last_point == 2 )
{
/* We're out and the last point was on the boundary.
* If the last point was the near boundary, nothing to do.
* If it was the far boundary, we need an interpolated point. */
if ( from != to && (
(ordinate_value_q == from && ordinate_value_p > from) ||
(ordinate_value_q == to && ordinate_value_p < to) ) )
{
double interpolation_value;
(ordinate_value_p > to) ? (interpolation_value = to) : (interpolation_value = from);
point_interpolate(q, p, r, hasz, hasm, ordinate, interpolation_value);
ptarray_append_point(dp, r, LW_FALSE);
LWDEBUGF(4, " [2] interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
}
}
else if ( i && ordinate_value_q < from && ordinate_value_p > to )
{
/* We just hopped over the whole range, from bottom to top,
* so we need to add *two* interpolated points! */
dp = ptarray_construct(hasz, hasm, 2);
/* Interpolate lower point. */
point_interpolate(p, q, r, hasz, hasm, ordinate, from);
ptarray_set_point4d(dp, 0, r);
/* Interpolate upper point. */
point_interpolate(p, q, r, hasz, hasm, ordinate, to);
ptarray_set_point4d(dp, 1, r);
}
else if ( i && ordinate_value_q > to && ordinate_value_p < from )
{
/* We just hopped over the whole range, from top to bottom,
* so we need to add *two* interpolated points! */
dp = ptarray_construct(hasz, hasm, 2);
/* Interpolate upper point. */
point_interpolate(p, q, r, hasz, hasm, ordinate, to);
ptarray_set_point4d(dp, 0, r);
/* Interpolate lower point. */
point_interpolate(p, q, r, hasz, hasm, ordinate, from);
ptarray_set_point4d(dp, 1, r);
}
/* We have an extant point-array, save it out to a multi-line. */
if ( dp )
{
LWDEBUG(4, "saving pointarray to multi-line (1)");
/* Only one point, so we have to make an lwpoint to hold this
* and set the overall output type to a generic collection. */
if ( dp->npoints == 1 )
{
LWPOINT *opoint = lwpoint_construct(line->srid, NULL, dp);
lwgeom_out->type = COLLECTIONTYPE;
lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, lwpoint_as_lwgeom(opoint));
}
else
{
LWLINE *oline = lwline_construct(line->srid, NULL, dp);
lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, lwline_as_lwgeom(oline));
}
/* Pointarray is now owned by lwgeom_out, so drop reference to it */
dp = NULL;
}
added_last_point = 0;
}
}
/* Still some points left to be saved out. */
if ( dp && dp->npoints > 0 )
{
LWDEBUG(4, "saving pointarray to multi-line (2)");
LWDEBUGF(4, "dp->npoints == %d", dp->npoints);
LWDEBUGF(4, "lwgeom_out->ngeoms == %d", lwgeom_out->ngeoms);
if ( dp->npoints == 1 )
{
LWPOINT *opoint = lwpoint_construct(line->srid, NULL, dp);
lwgeom_out->type = COLLECTIONTYPE;
lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, lwpoint_as_lwgeom(opoint));
}
else
{
LWLINE *oline = lwline_construct(line->srid, NULL, dp);
lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, lwline_as_lwgeom(oline));
}
/* Pointarray is now owned by lwgeom_out, so drop reference to it */
dp = NULL;
}
lwfree(p);
lwfree(q);
lwfree(r);
if ( lwgeom_out->bbox && lwgeom_out->ngeoms > 0 )
{
lwgeom_refresh_bbox((LWGEOM*)lwgeom_out);
}
return lwgeom_out;
}
LWCOLLECTION*
lwgeom_clip_to_ordinate_range(const LWGEOM *lwin, char ordinate, double from, double to, double offset)
{
LWCOLLECTION *out_col;
LWCOLLECTION *out_offset;
uint32_t i;
if ( ! lwin )
lwerror("lwgeom_clip_to_ordinate_range: null input geometry!");
switch ( lwin->type )
{
case LINETYPE:
out_col = lwline_clip_to_ordinate_range((LWLINE*)lwin, ordinate, from, to);
break;
case MULTILINETYPE:
out_col = lwmline_clip_to_ordinate_range((LWMLINE*)lwin, ordinate, from, to);
break;
case MULTIPOINTTYPE:
out_col = lwmpoint_clip_to_ordinate_range((LWMPOINT*)lwin, ordinate, from, to);
break;
case POINTTYPE:
out_col = lwpoint_clip_to_ordinate_range((LWPOINT*)lwin, ordinate, from, to);
break;
default:
lwerror("This function does not accept %s geometries.", lwtype_name(lwin->type));
return NULL;;
}
/* Stop if result is NULL */
if ( out_col == NULL )
lwerror("lwgeom_clip_to_ordinate_range clipping routine returned NULL");
/* Return if we aren't going to offset the result */
if (FP_IS_ZERO(offset) ||
lwgeom_is_empty(lwcollection_as_lwgeom(out_col)))
return out_col;
/* Construct a collection to hold our outputs. */
/* Things get ugly: GEOS offset drops Z's and M's so we have to drop ours */
out_offset = lwcollection_construct_empty(MULTILINETYPE, lwin->srid, 0, 0);
/* Try and offset the linear portions of the return value */
for ( i = 0; i < out_col->ngeoms; i++ )
{
int type = out_col->geoms[i]->type;
if ( type == POINTTYPE )
{
lwnotice("lwgeom_clip_to_ordinate_range cannot offset a clipped point");
continue;
}
else if ( type == LINETYPE )
{
/* lwgeom_offsetcurve(line, offset, quadsegs, joinstyle (round), mitrelimit) */
LWGEOM *lwoff = lwgeom_offsetcurve(lwgeom_as_lwline(out_col->geoms[i]), offset, 8, 1, 5.0);
if ( ! lwoff )
{
lwerror("lwgeom_offsetcurve returned null");
}
lwcollection_add_lwgeom(out_offset, lwoff);
}
else
{
lwerror("lwgeom_clip_to_ordinate_range found an unexpected type (%s) in the offset routine",lwtype_name(type));
}
}
return out_offset;
}
LWCOLLECTION*
lwgeom_locate_between(const LWGEOM *lwin, double from, double to, double offset)
{
if ( ! lwgeom_has_m(lwin) )
lwerror("Input geometry does not have a measure dimension");
return lwgeom_clip_to_ordinate_range(lwin, 'M', from, to, offset);
}
double
lwgeom_interpolate_point(const LWGEOM *lwin, const LWPOINT *lwpt)
{
POINT4D p, p_proj;
double ret = 0.0;
if ( ! lwin )
lwerror("lwgeom_interpolate_point: null input geometry!");
if ( ! lwgeom_has_m(lwin) )
lwerror("Input geometry does not have a measure dimension");
if ( lwgeom_is_empty(lwin) || lwpoint_is_empty(lwpt) )
lwerror("Input geometry is empty");
switch ( lwin->type )
{
case LINETYPE:
{
LWLINE *lwline = lwgeom_as_lwline(lwin);
lwpoint_getPoint4d_p(lwpt, &p);
ret = ptarray_locate_point(lwline->points, &p, NULL, &p_proj);
ret = p_proj.m;
break;
}
default:
lwerror("This function does not accept %s geometries.", lwtype_name(lwin->type));
}
return ret;
}
/*
* Time of closest point of approach
*
* Given two vectors (p1-p2 and q1-q2) and
* a time range (t1-t2) return the time in which
* a point p is closest to a point q on their
* respective vectors, and the actual points
*
* Here we use algorithm from softsurfer.com
* that can be found here
* http://softsurfer.com/Archive/algorithm_0106/algorithm_0106.htm
*
* @param p0 start of first segment, will be set to actual
* closest point of approach on segment.
* @param p1 end of first segment
* @param q0 start of second segment, will be set to actual
* closest point of approach on segment.
* @param q1 end of second segment
* @param t0 start of travel time
* @param t1 end of travel time
*
* @return time of closest point of approach
*
*/
static double
segments_tcpa(POINT4D* p0, const POINT4D* p1,
POINT4D* q0, const POINT4D* q1,
double t0, double t1)
{
POINT3DZ pv; /* velocity of p, aka u */
POINT3DZ qv; /* velocity of q, aka v */
POINT3DZ dv; /* velocity difference */
POINT3DZ w0; /* vector between first points */
/*
lwnotice("FROM %g,%g,%g,%g -- %g,%g,%g,%g",
p0->x, p0->y, p0->z, p0->m,
p1->x, p1->y, p1->z, p1->m);
lwnotice(" TO %g,%g,%g,%g -- %g,%g,%g,%g",
q0->x, q0->y, q0->z, q0->m,
q1->x, q1->y, q1->z, q1->m);
*/
/* PV aka U */
pv.x = ( p1->x - p0->x );
pv.y = ( p1->y - p0->y );
pv.z = ( p1->z - p0->z );
/*lwnotice("PV: %g, %g, %g", pv.x, pv.y, pv.z);*/
/* QV aka V */
qv.x = ( q1->x - q0->x );
qv.y = ( q1->y - q0->y );
qv.z = ( q1->z - q0->z );
/*lwnotice("QV: %g, %g, %g", qv.x, qv.y, qv.z);*/
dv.x = pv.x - qv.x;
dv.y = pv.y - qv.y;
dv.z = pv.z - qv.z;
/*lwnotice("DV: %g, %g, %g", dv.x, dv.y, dv.z);*/
double dv2 = DOT(dv,dv);
/*lwnotice("DOT: %g", dv2);*/
if ( dv2 == 0.0 )
{
/* Distance is the same at any time, we pick the earliest */
return t0;
}
/* Distance at any given time, with t0 */
w0.x = ( p0->x - q0->x );
w0.y = ( p0->y - q0->y );
w0.z = ( p0->z - q0->z );
/*lwnotice("W0: %g, %g, %g", w0.x, w0.y, w0.z);*/
/* Check that at distance dt w0 is distance */
/* This is the fraction of measure difference */
double t = -DOT(w0,dv) / dv2;
/*lwnotice("CLOSEST TIME (fraction): %g", t);*/
if ( t > 1.0 )
{
/* Getting closer as we move to the end */
/*lwnotice("Converging");*/
t = 1;
}
else if ( t < 0.0 )
{
/*lwnotice("Diverging");*/
t = 0;
}
/* Interpolate the actual points now */
p0->x += pv.x * t;
p0->y += pv.y * t;
p0->z += pv.z * t;
q0->x += qv.x * t;
q0->y += qv.y * t;
q0->z += qv.z * t;
t = t0 + (t1 - t0) * t;
/*lwnotice("CLOSEST TIME (real): %g", t);*/
return t;
}
static int
ptarray_collect_mvals(const POINTARRAY *pa, double tmin, double tmax, double *mvals)
{
POINT4D pbuf;
uint32_t i, n=0;
for (i=0; i<pa->npoints; ++i)
{
getPoint4d_p(pa, i, &pbuf); /* could be optimized */
if ( pbuf.m >= tmin && pbuf.m <= tmax )
mvals[n++] = pbuf.m;