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https://git.osgeo.org/gitea/postgis/postgis
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430 lines
12 KiB
C
430 lines
12 KiB
C
/**********************************************************************
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* $Id$
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*
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* PostGIS - Spatial Types for PostgreSQL
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* http://postgis.refractions.net
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* Copyright 2011 Paul Ramsey
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*
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* This is free software; you can redistribute and/or modify it under
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* the terms of the GNU General Public Licence. See the COPYING file.
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*
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**********************************************************************/
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#include "liblwgeom_internal.h"
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#include "lwgeom_log.h"
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/**
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* Given a POINT4D and an ordinate number, return
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* the value of the ordinate.
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* @param p input point
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* @param ordinate number (1=x, 2=y, 3=z, 4=m)
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* @return d value at that ordinate
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*/
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double lwpoint_get_ordinate(const POINT4D *p, int ordinate)
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{
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if ( ! p )
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{
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lwerror("Null input geometry.");
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return 0.0;
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}
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if ( ordinate > 3 || ordinate < 0 )
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{
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lwerror("Cannot extract ordinate %d.", ordinate);
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return 0.0;
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}
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if ( ordinate == 3 )
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return p->m;
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if ( ordinate == 2 )
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return p->z;
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if ( ordinate == 1 )
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return p->y;
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return p->x;
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}
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/**
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* Given a point, ordinate number and value, set that ordinate on the
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* point.
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*/
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void lwpoint_set_ordinate(POINT4D *p, int ordinate, double value)
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{
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if ( ! p )
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{
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lwerror("Null input geometry.");
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return;
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}
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if ( ordinate > 3 || ordinate < 0 )
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{
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lwerror("Cannot extract ordinate %d.", ordinate);
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return;
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}
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LWDEBUGF(4, " setting ordinate %d to %g", ordinate, value);
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switch ( ordinate )
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{
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case 3:
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p->m = value;
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return;
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case 2:
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p->z = value;
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return;
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case 1:
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p->y = value;
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return;
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case 0:
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p->x = value;
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return;
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}
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}
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/**
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* Given two points, a dimensionality, an ordinate, and an interpolation value
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* generate a new point that is proportionally between the input points,
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* using the values in the provided dimension as the scaling factors.
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*/
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int lwpoint_interpolate(const POINT4D *p1, const POINT4D *p2, POINT4D *p, int ndims, int ordinate, double interpolation_value)
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{
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double p1_value = lwpoint_get_ordinate(p1, ordinate);
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double p2_value = lwpoint_get_ordinate(p2, ordinate);
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double proportion;
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int i = 0;
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if ( ordinate < 0 || ordinate >= ndims )
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{
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lwerror("Ordinate (%d) is not within ndims (%d).", ordinate, ndims);
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return 0;
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}
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if ( FP_MIN(p1_value, p2_value) > interpolation_value ||
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FP_MAX(p1_value, p2_value) < interpolation_value )
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{
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lwerror("Cannot interpolate to a value (%g) not between the input points (%g, %g).", interpolation_value, p1_value, p2_value);
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return 0;
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}
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proportion = fabs((interpolation_value - p1_value) / (p2_value - p1_value));
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for ( i = 0; i < ndims; i++ )
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{
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double newordinate = 0.0;
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p1_value = lwpoint_get_ordinate(p1, i);
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p2_value = lwpoint_get_ordinate(p2, i);
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newordinate = p1_value + proportion * (p2_value - p1_value);
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lwpoint_set_ordinate(p, i, newordinate);
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LWDEBUGF(4, " clip ordinate(%d) p1_value(%g) p2_value(%g) proportion(%g) newordinate(%g) ", i, p1_value, p2_value, proportion, newordinate );
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}
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return 1;
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}
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/**
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* Clip an input MULTILINESTRING between two values, on any ordinate input.
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*/
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LWCOLLECTION *lwmline_clip_to_ordinate_range(LWMLINE *mline, int ordinate, double from, double to)
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{
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LWCOLLECTION *lwgeom_out = NULL;
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if ( ! mline )
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{
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lwerror("Null input geometry.");
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return NULL;
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}
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if ( mline->ngeoms == 1)
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{
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lwgeom_out = lwline_clip_to_ordinate_range(mline->geoms[0], ordinate, from, to);
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}
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else
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{
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LWCOLLECTION *col;
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char hasz = FLAGS_GET_Z(mline->flags);
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char hasm = FLAGS_GET_M(mline->flags);
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int i, j;
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char homogeneous = 1;
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size_t geoms_size = 0;
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lwgeom_out = lwcollection_construct_empty(MULTILINETYPE, mline->srid, hasz, hasm);
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FLAGS_SET_Z(lwgeom_out->flags, hasz);
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FLAGS_SET_M(lwgeom_out->flags, hasm);
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for ( i = 0; i < mline->ngeoms; i ++ )
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{
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col = lwline_clip_to_ordinate_range(mline->geoms[i], ordinate, from, to);
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if ( col )
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{
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/* Something was left after the clip. */
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if ( lwgeom_out->ngeoms + col->ngeoms > geoms_size )
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{
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geoms_size += 16;
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if ( lwgeom_out->geoms )
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{
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lwgeom_out->geoms = lwrealloc(lwgeom_out->geoms, geoms_size * sizeof(LWGEOM*));
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}
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else
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{
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lwgeom_out->geoms = lwalloc(geoms_size * sizeof(LWGEOM*));
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}
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}
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for ( j = 0; j < col->ngeoms; j++ )
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{
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lwgeom_out->geoms[lwgeom_out->ngeoms] = col->geoms[j];
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lwgeom_out->ngeoms++;
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}
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if ( col->type != mline->type )
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{
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homogeneous = 0;
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}
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/* Shallow free the struct, leaving the geoms behind. */
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if ( col->bbox ) lwfree(col->bbox);
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lwfree(col->geoms);
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lwfree(col);
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}
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}
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lwgeom_drop_bbox((LWGEOM*)lwgeom_out);
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lwgeom_add_bbox((LWGEOM*)lwgeom_out);
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if ( ! homogeneous )
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{
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lwgeom_out->type = COLLECTIONTYPE;
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}
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}
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if ( ! lwgeom_out || lwgeom_out->ngeoms == 0 ) /* Nothing left after clip. */
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{
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return NULL;
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}
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return lwgeom_out;
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}
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/**
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* Take in a LINESTRING and return a MULTILINESTRING of those portions of the
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* LINESTRING between the from/to range for the specified ordinate (XYZM)
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*/
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LWCOLLECTION *lwline_clip_to_ordinate_range(LWLINE *line, int ordinate, double from, double to)
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{
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POINTARRAY *pa_in = NULL;
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LWCOLLECTION *lwgeom_out = NULL;
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POINTARRAY *dp = NULL;
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int i, rv;
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int added_last_point = 0;
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POINT4D *p = NULL, *q = NULL, *r = NULL;
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double ordinate_value_p = 0.0, ordinate_value_q = 0.0;
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char hasz = FLAGS_GET_Z(line->flags);
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char hasm = FLAGS_GET_M(line->flags);
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char dims = FLAGS_NDIMS(line->flags);
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/* Null input, nothing we can do. */
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if ( ! line )
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{
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lwerror("Null input geometry.");
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return NULL;
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}
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/* Ensure 'from' is less than 'to'. */
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if ( to < from )
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{
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double t = from;
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from = to;
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to = t;
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}
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LWDEBUGF(4, "from = %g, to = %g, ordinate = %d", from, to, ordinate);
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LWDEBUGF(4, "%s", lwgeom_to_ewkt((LWGEOM*)line));
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/* Asking for an ordinate we don't have. Error. */
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if ( ordinate >= dims )
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{
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lwerror("Cannot clip on ordinate %d in a %d-d geometry.", ordinate, dims);
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return NULL;
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}
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/* Prepare our working point objects. */
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p = lwalloc(sizeof(POINT4D));
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q = lwalloc(sizeof(POINT4D));
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r = lwalloc(sizeof(POINT4D));
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/* Construct a collection to hold our outputs. */
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lwgeom_out = lwcollection_construct_empty(MULTILINETYPE, line->srid, hasz, hasm);
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/* Get our input point array */
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pa_in = line->points;
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for ( i = 0; i < pa_in->npoints; i++ )
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{
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LWDEBUGF(4, "Point #%d", i);
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LWDEBUGF(4, "added_last_point %d", added_last_point);
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if ( i > 0 )
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{
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*q = *p;
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ordinate_value_q = ordinate_value_p;
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}
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rv = getPoint4d_p(pa_in, i, p);
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ordinate_value_p = lwpoint_get_ordinate(p, ordinate);
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LWDEBUGF(4, " ordinate_value_p %g (current)", ordinate_value_p);
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LWDEBUGF(4, " ordinate_value_q %g (previous)", ordinate_value_q);
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/* Is this point inside the ordinate range? Yes. */
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if ( ordinate_value_p >= from && ordinate_value_p <= to )
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{
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LWDEBUGF(4, " inside ordinate range (%g, %g)", from, to);
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if ( ! added_last_point )
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{
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LWDEBUG(4," new ptarray required");
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/* We didn't add the previous point, so this is a new segment.
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* Make a new point array. */
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dp = ptarray_construct_empty(hasz, hasm, 32);
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/* We're transiting into the range so add an interpolated
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* point at the range boundary.
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* If we're on a boundary and crossing from the far side,
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* we also need an interpolated point. */
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if ( i > 0 && ( /* Don't try to interpolate if this is the first point */
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( ordinate_value_p > from && ordinate_value_p < to ) || /* Inside */
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( ordinate_value_p == from && ordinate_value_q > to ) || /* Hopping from above */
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( ordinate_value_p == to && ordinate_value_q < from ) ) ) /* Hopping from below */
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{
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double interpolation_value;
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(ordinate_value_q > to) ? (interpolation_value = to) : (interpolation_value = from);
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rv = lwpoint_interpolate(q, p, r, dims, ordinate, interpolation_value);
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rv = ptarray_append_point(dp, r, LW_FALSE);
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LWDEBUGF(4, "[0] interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
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}
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}
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/* Add the current vertex to the point array. */
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rv = ptarray_append_point(dp, p, LW_FALSE);
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if ( ordinate_value_p == from || ordinate_value_p == to )
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{
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added_last_point = 2; /* Added on boundary. */
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}
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else
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{
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added_last_point = 1; /* Added inside range. */
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}
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}
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/* Is this point inside the ordinate range? No. */
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else
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{
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LWDEBUGF(4, " added_last_point (%d)", added_last_point);
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if ( added_last_point == 1 )
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{
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/* We're transiting out of the range, so add an interpolated point
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* to the point array at the range boundary. */
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double interpolation_value;
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(ordinate_value_p > to) ? (interpolation_value = to) : (interpolation_value = from);
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rv = lwpoint_interpolate(q, p, r, dims, ordinate, interpolation_value);
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rv = ptarray_append_point(dp, r, LW_FALSE);
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LWDEBUGF(4, " [1] interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
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}
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else if ( added_last_point == 2 )
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{
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/* We're out and the last point was on the boundary.
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* If the last point was the near boundary, nothing to do.
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* If it was the far boundary, we need an interpolated point. */
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if ( from != to && (
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(ordinate_value_q == from && ordinate_value_p > from) ||
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(ordinate_value_q == to && ordinate_value_p < to) ) )
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{
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double interpolation_value;
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(ordinate_value_p > to) ? (interpolation_value = to) : (interpolation_value = from);
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rv = lwpoint_interpolate(q, p, r, dims, ordinate, interpolation_value);
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rv = ptarray_append_point(dp, r, LW_FALSE);
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LWDEBUGF(4, " [2] interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
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}
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}
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else if ( i && ordinate_value_q < from && ordinate_value_p > to )
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{
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/* We just hopped over the whole range, from bottom to top,
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* so we need to add *two* interpolated points! */
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dp = ptarray_construct(hasz, hasm, 2);
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/* Interpolate lower point. */
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rv = lwpoint_interpolate(p, q, r, dims, ordinate, from);
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ptarray_set_point4d(dp, 0, r);
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/* Interpolate upper point. */
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rv = lwpoint_interpolate(p, q, r, dims, ordinate, to);
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ptarray_set_point4d(dp, 1, r);
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}
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else if ( i && ordinate_value_q > to && ordinate_value_p < from )
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{
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/* We just hopped over the whole range, from top to bottom,
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* so we need to add *two* interpolated points! */
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dp = ptarray_construct(hasz, hasm, 2);
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/* Interpolate upper point. */
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rv = lwpoint_interpolate(p, q, r, dims, ordinate, to);
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ptarray_set_point4d(dp, 0, r);
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/* Interpolate lower point. */
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rv = lwpoint_interpolate(p, q, r, dims, ordinate, from);
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ptarray_set_point4d(dp, 1, r);
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}
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/* We have an extant point-array, save it out to a multi-line. */
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if ( dp )
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{
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LWDEBUG(4, "saving pointarray to multi-line (1)");
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/* Only one point, so we have to make an lwpoint to hold this
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* and set the overall output type to a generic collection. */
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if ( dp->npoints == 1 )
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{
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LWPOINT *opoint = lwpoint_construct(line->srid, NULL, dp);
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lwgeom_out->type = COLLECTIONTYPE;
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lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, lwpoint_as_lwgeom(opoint));
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}
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else
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{
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LWLINE *oline = lwline_construct(line->srid, NULL, dp);
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lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, lwline_as_lwgeom(oline));
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}
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/* Pointarray is now owned by lwgeom_out, so drop reference to it */
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dp = NULL;
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}
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added_last_point = 0;
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}
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}
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/* Still some points left to be saved out. */
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if ( dp && dp->npoints > 0 )
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{
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LWDEBUG(4, "saving pointarray to multi-line (2)");
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LWDEBUGF(4, "dp->npoints == %d", dp->npoints);
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LWDEBUGF(4, "lwgeom_out->ngeoms == %d", lwgeom_out->ngeoms);
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if ( dp->npoints == 1 )
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{
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LWPOINT *opoint = lwpoint_construct(line->srid, NULL, dp);
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lwgeom_out->type = COLLECTIONTYPE;
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lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, lwpoint_as_lwgeom(opoint));
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}
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else
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{
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LWLINE *oline = lwline_construct(line->srid, NULL, dp);
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lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, lwline_as_lwgeom(oline));
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}
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/* Pointarray is now owned by lwgeom_out, so drop reference to it */
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dp = NULL;
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}
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lwfree(p);
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lwfree(q);
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lwfree(r);
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if ( lwgeom_out->ngeoms > 0 )
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{
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lwgeom_drop_bbox((LWGEOM*)lwgeom_out);
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lwgeom_add_bbox((LWGEOM*)lwgeom_out);
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return lwgeom_out;
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}
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return NULL;
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} |