lwgeom_clip_to_ordinate_range()

LWCOLLECTION* lwgeom_clip_to_ordinate_range	(	const LWGEOM *	lwin,
		char	ordinate,
		double	from,
		double	to,
		double	offset
	)

Given a geometry clip based on the from/to range of one of its ordinates (x, y, z, m).

Use for m- and z- clipping.

Definition at line 778 of file lwlinearreferencing.c.

{
        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(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;
}

References FP_IS_ZERO, LWCOLLECTION::geoms, LINETYPE, lwcollection_add_lwgeom(), lwcollection_as_lwgeom(), lwcollection_construct_empty(), lwerror(), lwgeom_is_empty(), lwgeom_offsetcurve(), lwline_clip_to_ordinate_range(), lwmline_clip_to_ordinate_range(), lwmpoint_clip_to_ordinate_range(), lwnotice(), lwpoint_clip_to_ordinate_range(), lwtype_name(), MULTILINETYPE, MULTIPOINTTYPE, LWCOLLECTION::ngeoms, POINTTYPE, LWGEOM::srid, LWGEOM::type, LWLINE::type, and ovdump::type.

Referenced by lwgeom_locate_between(), ST_LocateBetween(), and ST_LocateBetweenElevations().

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