Ejemplo n.º 1
0
/* Calculate the volume of the intersection of the boxes. */
static float gidx_inter_volume(GIDX *a, GIDX *b)
{
	int i;
	float result;

	POSTGIS_DEBUG(5,"entered function");

	if ( a == NULL || b == NULL )
	{
		elog(ERROR, "gidx_inter_volume received a null argument");
		return 0.0;
	}

	/* Ensure 'a' has the most dimensions. */
	gidx_dimensionality_check(&a, &b);

	/* Initialize with minimal length of first dimension. */
	result = Min(GIDX_GET_MAX(a,0),GIDX_GET_MAX(b,0)) - Max(GIDX_GET_MIN(a,0),GIDX_GET_MIN(b,0));

	/* If they are disjoint (max < min) then return zero. */
	if ( result < 0.0 ) return 0.0;

	/* Continue for remaining dimensions. */
	for ( i = 1; i < GIDX_NDIMS(b); i++ )
	{
		float width = Min(GIDX_GET_MAX(a,i),GIDX_GET_MAX(b,i)) - Max(GIDX_GET_MIN(a,i),GIDX_GET_MIN(b,i));
		if ( width < 0.0 ) return 0.0;
		/* Multiply by minimal length of remaining dimensions. */
		result *= width;
	}
	POSTGIS_DEBUGF(5, "volume( %s intersection %s ) = %.12g", gidx_to_string(a), gidx_to_string(b), result);
	return result;
}
Ejemplo n.º 2
0
/*
** Overlapping GIDX box test.
**
** Box(A) Overlap Box(B) IFF (pt(a)LL < pt(B)UR) && (pt(b)LL < pt(a)UR)
*/
static bool gidx_overlaps(GIDX *a, GIDX *b)
{
	int i;
	int ndims_b;
	POSTGIS_DEBUG(5, "entered function");
	if ( (a == NULL) || (b == NULL) ) return FALSE;

	/* Ensure 'a' has the most dimensions. */
	gidx_dimensionality_check(&a, &b);

	ndims_b = GIDX_NDIMS(b);

	/* compare within the dimensions of (b) */
	for ( i = 0; i < ndims_b; i++ )
	{
		if ( GIDX_GET_MIN(a,i) > GIDX_GET_MAX(b,i) )
			return FALSE;
		if ( GIDX_GET_MIN(b,i) > GIDX_GET_MAX(a,i) )
			return FALSE;
	}

	/* compare to zero those dimensions in (a) absent in (b) */
	for ( i = ndims_b; i < GIDX_NDIMS(a); i++ )
	{
		if ( GIDX_GET_MIN(a,i) > 0.0 )
			return FALSE;
		if ( GIDX_GET_MAX(a,i) < 0.0 )
			return FALSE;
	}
	return TRUE;
}
Ejemplo n.º 3
0
/* Enlarge b_union to contain b_new. If b_new contains more
   dimensions than b_union, expand b_union to contain those dimensions. */
static void gidx_merge(GIDX **b_union, GIDX *b_new)
{
	int i, dims_union, dims_new;
	Assert(b_union);
	Assert(*b_union);
	Assert(b_new);

	dims_union = GIDX_NDIMS(*b_union);
	dims_new = GIDX_NDIMS(b_new);

	POSTGIS_DEBUGF(4, "merging gidx (%s) into gidx (%s)", gidx_to_string(b_new), gidx_to_string(*b_union));

	if ( dims_new > dims_union )
	{
		POSTGIS_DEBUGF(5, "reallocating b_union from %d dims to %d dims", dims_union, dims_new);
		*b_union = (GIDX*)repalloc(*b_union, GIDX_SIZE(dims_new));
		SET_VARSIZE(*b_union, VARSIZE(b_new));
		dims_union = dims_new;
	}

	for ( i = 0; i < dims_new; i++ )
	{
		/* Adjust minimums */
		GIDX_SET_MIN(*b_union, i, Min(GIDX_GET_MIN(*b_union,i),GIDX_GET_MIN(b_new,i)));
		/* Adjust maximums */
		GIDX_SET_MAX(*b_union, i, Max(GIDX_GET_MAX(*b_union,i),GIDX_GET_MAX(b_new,i)));
	}

	POSTGIS_DEBUGF(5, "merge complete (%s)", gidx_to_string(*b_union));
	return;
}
Ejemplo n.º 4
0
/*
** Equality GIDX test.
**
** Box(A) EQUALS Box(B) IFF (pt(A)LL == pt(B)LL) && (pt(A)UR == pt(B)UR)
*/
static bool gidx_equals(GIDX *a, GIDX *b)
{
	int i;

	POSTGIS_DEBUG(5, "entered function");

	if ( (a == NULL) && (b == NULL) ) return TRUE;
	if ( (a == NULL) || (b == NULL) ) return FALSE;

	/* Ensure 'a' has the most dimensions. */
	gidx_dimensionality_check(&a, &b);

	/* For all shared dimensions min(a) == min(b), max(a) == max(b) */
	for (i = 0; i < GIDX_NDIMS(b); i++)
	{
		if ( GIDX_GET_MIN(a,i) != GIDX_GET_MIN(b,i) )
			return FALSE;
		if ( GIDX_GET_MAX(a,i) != GIDX_GET_MAX(b,i) )
			return FALSE;
	}
	/* For all unshared dimensions min(a) == 0.0, max(a) == 0.0 */
	for (i = GIDX_NDIMS(b); i < GIDX_NDIMS(a); i++)
	{
		if ( GIDX_GET_MIN(a,i) != 0.0 )
			return FALSE;
		if ( GIDX_GET_MAX(a,i) != 0.0 )
			return FALSE;
	}
	return TRUE;
}
Ejemplo n.º 5
0
/*
** GiST support function. Called from geography_gist_consistent below.
*/
static inline bool geography_gist_consistent_internal(GIDX *key, GIDX *query, StrategyNumber strategy)
{
	bool		retval;

	POSTGIS_DEBUGF(4, "[GIST] internal consistent, strategy [%d], count[%i], bounds[%.12g %.12g %.12g, %.12g %.12g %.12g]",
	               strategy, geog_counter_internal++,
	               GIDX_GET_MIN(query, 0), GIDX_GET_MIN(query, 1), GIDX_GET_MIN(query, 2),
	               GIDX_GET_MAX(query, 0), GIDX_GET_MAX(query, 1), GIDX_GET_MAX(query, 2) );

	switch (strategy)
	{
	case RTOverlapStrategyNumber:
		retval = (bool) gidx_overlaps(key, query);
		break;
	case RTSameStrategyNumber:
	case RTContainsStrategyNumber:
	case RTOldContainsStrategyNumber:
		retval = (bool) gidx_contains(key, query);
		break;
	case RTContainedByStrategyNumber:
	case RTOldContainedByStrategyNumber:
		retval = (bool) gidx_overlaps(key, query);
		break;
	default:
		retval = FALSE;
	}
	return (retval);
}
Ejemplo n.º 6
0
void gbox_from_gidx(GIDX *a, GBOX *gbox)
{
	gbox->xmin = (double)GIDX_GET_MIN(a,0);
	gbox->ymin = (double)GIDX_GET_MIN(a,1);
	gbox->zmin = (double)GIDX_GET_MIN(a,2);
	gbox->xmax = (double)GIDX_GET_MAX(a,0);
	gbox->ymax = (double)GIDX_GET_MAX(a,1);
	gbox->zmax = (double)GIDX_GET_MAX(a,2);
}
Ejemplo n.º 7
0
/* Calculate the volume (in n-d units) of the GIDX */
static float gidx_volume(GIDX *a)
{
	float result;
	int i;
	if ( a == NULL )
	{
		/*		elog(ERROR, "gidx_volume received a null argument"); */
		return 0.0;
	}
	result = GIDX_GET_MAX(a,0) - GIDX_GET_MIN(a,0);
	for ( i = 1; i < GIDX_NDIMS(a); i++ )
		result *= (GIDX_GET_MAX(a,i) - GIDX_GET_MIN(a,i));
	POSTGIS_DEBUGF(5, "calculated volume of %s as %.12g", gidx_to_string(a), result);
	return result;
}
Ejemplo n.º 8
0
/**
* Peak into a #GSERIALIZED datum to find the bounding box. If the
* box is there, copy it out and return it. If not, calculate the box from the
* full object and return the box based on that. If no box is available,
* return #LW_FAILURE, otherwise #LW_SUCCESS.
*/
int 
gserialized_datum_get_gidx_p(Datum gsdatum, GIDX *gidx)
{
	GSERIALIZED *gpart;
	int result = LW_SUCCESS;

	POSTGIS_DEBUG(4, "entered function");

	/*
	** The most info we need is the 8 bytes of serialized header plus the 32 bytes
	** of floats necessary to hold the 8 floats of the largest XYZM index
	** bounding box, so 40 bytes.
	*/
	gpart = (GSERIALIZED*)PG_DETOAST_DATUM_SLICE(gsdatum, 0, 40);

	POSTGIS_DEBUGF(4, "got flags %d", gpart->flags);

	/* Do we even have a serialized bounding box? */
	if ( FLAGS_GET_BBOX(gpart->flags) )
	{
		/* Yes! Copy it out into the GIDX! */
		size_t size = gbox_serialized_size(gpart->flags);
		POSTGIS_DEBUG(4, "copying box out of serialization");
		memcpy(gidx->c, gpart->data, size);
		/* if M is present but Z is not, pad Z and shift M */
		if ( FLAGS_GET_M(gpart->flags) && ! FLAGS_GET_Z(gpart->flags) )
		{
			size += 2 * sizeof(float);
			GIDX_SET_MIN(gidx,3,GIDX_GET_MIN(gidx,2));
			GIDX_SET_MAX(gidx,3,GIDX_GET_MAX(gidx,2));
			GIDX_SET_MIN(gidx,2,-1*FLT_MAX);
			GIDX_SET_MAX(gidx,2,FLT_MAX);
		}
		SET_VARSIZE(gidx, VARHDRSZ + size);
		result = LW_SUCCESS;
	}
	else
	{
		/* No, we need to calculate it from the full object. */
		GSERIALIZED *g = (GSERIALIZED*)PG_DETOAST_DATUM(gsdatum);
		LWGEOM *lwgeom = lwgeom_from_gserialized(g);
		GBOX gbox;
		if ( lwgeom_calculate_gbox(lwgeom, &gbox) == LW_FAILURE )
		{
			POSTGIS_DEBUG(4, "could not calculate bbox, returning failure");
			lwgeom_free(lwgeom);
			return LW_FAILURE;
		}
		lwgeom_free(lwgeom);
		result = gidx_from_gbox_p(gbox, gidx);
	}
	
	if ( result == LW_SUCCESS )
	{
		POSTGIS_DEBUGF(4, "got gidx %s", gidx_to_string(gidx));
	}

	return result;
}
Ejemplo n.º 9
0
/* Ensure all minimums are below maximums. */
static inline void gidx_validate(GIDX *b)
{
	int i;
	Assert(b);
	POSTGIS_DEBUGF(5,"validating gidx (%s)", gidx_to_string(b));
	for ( i = 0; i < GIDX_NDIMS(b); i++ )
	{
		if ( GIDX_GET_MIN(b,i) > GIDX_GET_MAX(b,i) )
		{
			float tmp;
			tmp = GIDX_GET_MIN(b,i);
			GIDX_SET_MIN(b,i,GIDX_GET_MAX(b,i));
			GIDX_SET_MAX(b,i,tmp);
		}
	}
	return;
}
Ejemplo n.º 10
0
/* Convert a gidx to a gbox */
static void gbox_from_gidx(GIDX *a, GBOX *gbox, int flags)
{
	gbox->xmin = (double)GIDX_GET_MIN(a,0);
	gbox->xmax = (double)GIDX_GET_MAX(a,0);

	gbox->ymin = (double)GIDX_GET_MIN(a,1);
	gbox->ymax = (double)GIDX_GET_MAX(a,1);

	if ( FLAGS_GET_Z(flags) ) {
		gbox->zmin = (double)GIDX_GET_MIN(a,2);
		gbox->zmax = (double)GIDX_GET_MAX(a,2);
	}

	if ( FLAGS_GET_M(flags) ) {
		gbox->mmin = (double)GIDX_GET_MIN(a,3);
		gbox->mmax = (double)GIDX_GET_MAX(a,3);
	}
}
Ejemplo n.º 11
0
/* Calculate the volume of the union of the boxes. Avoids creating an intermediate box. */
static float gidx_union_volume(GIDX *a, GIDX *b)
{
	float result;
	int i;
	int ndims_a, ndims_b;

	POSTGIS_DEBUG(5,"entered function");

	if ( a == NULL && b == NULL )
	{
		elog(ERROR, "gidx_union_volume received two null arguments");
		return 0.0;
	}
	if ( a == NULL )
		return gidx_volume(b);

	if ( b == NULL )
		return gidx_volume(a);

	/* Ensure 'a' has the most dimensions. */
	gidx_dimensionality_check(&a, &b);

	ndims_a = GIDX_NDIMS(a);
	ndims_b = GIDX_NDIMS(b);

	/* Initialize with maximal length of first dimension. */
	result = Max(GIDX_GET_MAX(a,0),GIDX_GET_MAX(b,0)) - Min(GIDX_GET_MIN(a,0),GIDX_GET_MIN(b,0));

	/* Multiply by maximal length of remaining dimensions. */
	for ( i = 1; i < ndims_b; i++ )
	{
		result *= (Max(GIDX_GET_MAX(a,i),GIDX_GET_MAX(b,i)) - Min(GIDX_GET_MIN(a,i),GIDX_GET_MIN(b,i)));
	}

	/* Add in dimensions of higher dimensional box. */
	for ( i = ndims_b; i < ndims_a; i++ )
	{
		result *= (GIDX_GET_MAX(a,i) - GIDX_GET_MIN(a,i));
	}

	POSTGIS_DEBUGF(5, "volume( %s union %s ) = %.12g", gidx_to_string(a), gidx_to_string(b), result);

	return result;
}
Ejemplo n.º 12
0
/*
** GIDX expansion, make d units bigger in all dimensions.
*/
void gidx_expand(GIDX *a, float d)
{
	int i;

	POSTGIS_DEBUG(5, "entered function");

	if ( a == NULL ) return;

	for (i = 0; i < GIDX_NDIMS(a); i++)
	{
		GIDX_SET_MIN(a, i, GIDX_GET_MIN(a, i) - d);
		GIDX_SET_MAX(a, i, GIDX_GET_MAX(a, i) + d);
	}
}
Ejemplo n.º 13
0
/*
** Containment GIDX test.
**
** Box(A) CONTAINS Box(B) IFF (pt(A)LL < pt(B)LL) && (pt(A)UR > pt(B)UR)
*/
static bool gidx_contains(GIDX *a, GIDX *b)
{
	int i, dims_a, dims_b;

	POSTGIS_DEBUG(5, "entered function");

	if ( (a == NULL) || (b == NULL) ) return FALSE;

	dims_a = GIDX_NDIMS(a);
	dims_b = GIDX_NDIMS(b);

	if ( dims_a < dims_b )
	{
		/*
		** If (b) is of higher dimensionality than (a) it can only be contained
		** if those higher dimensions are zeroes.
		*/
		for (i = dims_a; i < dims_b; i++)
		{
			if ( GIDX_GET_MIN(b,i) != 0 )
				return FALSE;
			if ( GIDX_GET_MAX(b,i) != 0 )
				return FALSE;
		}
	}

	/* Excess dimensions of (a), don't matter, it just has to contain (b) in (b)'s dimensions */
	for (i = 0; i < Min(dims_a, dims_b); i++)
	{
		if ( GIDX_GET_MIN(a,i) > GIDX_GET_MIN(b,i) )
			return FALSE;
		if ( GIDX_GET_MAX(a,i) < GIDX_GET_MAX(b,i) )
			return FALSE;
	}

	return TRUE;
}
Ejemplo n.º 14
0
static char* gidx_to_string(GIDX *a)
{
	char *str, *rv;
	int i, ndims;

	if ( a == NULL )
		return pstrdup("<NULLPTR>");

	str = (char*)palloc(128);
	rv = str;
	ndims = GIDX_NDIMS(a);

	str += sprintf(str, "GIDX(");
	for ( i = 0; i < ndims; i++ )
		str += sprintf(str, " %.12g", GIDX_GET_MIN(a,i));
	str += sprintf(str, ",");
	for ( i = 0; i < ndims; i++ )
		str += sprintf(str, " %.12g", GIDX_GET_MAX(a,i));
	str += sprintf(str, " )");

	return rv;
}
Ejemplo n.º 15
0
/*
** Utility function to return the center point of a
** geocentric bounding box. We don't divide by two
** because we're only using the values for comparison.
*/
static void geography_gidx_center(GIDX *gidx, POINT3D *p)
{
	p->x = GIDX_GET_MIN(gidx, 0) + GIDX_GET_MAX(gidx, 0);
	p->y = GIDX_GET_MIN(gidx, 1) + GIDX_GET_MAX(gidx, 1);
	p->z = GIDX_GET_MIN(gidx, 2) + GIDX_GET_MAX(gidx, 2);
}
Ejemplo n.º 16
0
Datum geography_gist_compress(PG_FUNCTION_ARGS)
{
	GISTENTRY *entry_in = (GISTENTRY*)PG_GETARG_POINTER(0);
	GISTENTRY *entry_out = NULL;
	char gidxmem[GIDX_MAX_SIZE];
	GIDX *bbox_out = (GIDX*)gidxmem;
	int result = G_SUCCESS;

	int i;

	POSTGIS_DEBUG(4, "[GIST] 'compress' function called");

	/*
	** Not a leaf key? There's nothing to do.
	** Return the input unchanged.
	*/
	if ( ! entry_in->leafkey )
	{
		POSTGIS_DEBUG(4, "[GIST] non-leafkey entry, returning input unaltered");
		PG_RETURN_POINTER(entry_in);
	}

	POSTGIS_DEBUG(4, "[GIST] processing leafkey input");
	entry_out = palloc(sizeof(GISTENTRY));

	/*
	** Null key? Make a copy of the input entry and
	** return.
	*/
	if ( DatumGetPointer(entry_in->key) == NULL )
	{
		POSTGIS_DEBUG(4, "[GIST] leafkey is null");
		gistentryinit(*entry_out, (Datum) 0, entry_in->rel,
		              entry_in->page, entry_in->offset, FALSE);
		POSTGIS_DEBUG(4, "[GIST] returning copy of input");
		PG_RETURN_POINTER(entry_out);
	}

	/* Extract our index key from the GiST entry. */
	result = geography_datum_gidx(entry_in->key, bbox_out);

	/* Is the bounding box valid (non-empty, non-infinite)? If not, return input uncompressed. */
	if ( result == G_FAILURE )
	{
		POSTGIS_DEBUG(4, "[GIST] empty geometry!");
		PG_RETURN_POINTER(entry_in);
	}

	POSTGIS_DEBUGF(4, "[GIST] got entry_in->key: %s", gidx_to_string(bbox_out));

	/* Check all the dimensions for finite values */
	for ( i = 0; i < GIDX_NDIMS(bbox_out); i++ )
	{
		if ( ! finite(GIDX_GET_MAX(bbox_out, i)) || ! finite(GIDX_GET_MIN(bbox_out, i)) )
		{
			POSTGIS_DEBUG(4, "[GIST] infinite geometry!");
			PG_RETURN_POINTER(entry_in);
		}
	}

	/* Enure bounding box has minimums below maximums. */
	gidx_validate(bbox_out);

	/* Prepare GISTENTRY for return. */
	gistentryinit(*entry_out, PointerGetDatum(gidx_copy(bbox_out)),
	              entry_in->rel, entry_in->page, entry_in->offset, FALSE);

	/* Return GISTENTRY. */
	POSTGIS_DEBUG(4, "[GIST] 'compress' function complete");
	PG_RETURN_POINTER(entry_out);
}
Ejemplo n.º 17
0
Datum geography_gist_picksplit(PG_FUNCTION_ARGS)
{

	GistEntryVector	*entryvec = (GistEntryVector*) PG_GETARG_POINTER(0);

	GIST_SPLITVEC *v = (GIST_SPLITVEC*) PG_GETARG_POINTER(1);
	OffsetNumber i;
	/* One union box for each half of the space. */
	GIDX **box_union;
	/* One offset number list for each half of the space. */
	OffsetNumber **list;
	/* One position index for each half of the space. */
	int *pos;
	GIDX *box_pageunion;
	GIDX *box_current;
	int direction = -1;
	bool all_entries_equal = true;
	OffsetNumber max_offset;
	int nbytes, ndims_pageunion, d;
	int posmax = -1;

	POSTGIS_DEBUG(4, "[GIST] 'picksplit' function called");

	/*
	** First calculate the bounding box and maximum number of dimensions in this page.
	*/

	max_offset = entryvec->n - 1;
	box_current = (GIDX*) DatumGetPointer(entryvec->vector[FirstOffsetNumber].key);
	box_pageunion = gidx_copy(box_current);

	/* Calculate the containing box (box_pageunion) for the whole page we are going to split. */
	for ( i = OffsetNumberNext(FirstOffsetNumber); i <= max_offset; i = OffsetNumberNext(i) )
	{
		box_current = (GIDX*) DatumGetPointer(entryvec->vector[i].key);

		if ( all_entries_equal == true && ! gidx_equals (box_pageunion, box_current) )
			all_entries_equal = false;

		gidx_merge( &box_pageunion, box_current );
	}

	POSTGIS_DEBUGF(3, "[GIST] box_pageunion: %s", gidx_to_string(box_pageunion));

	/* Every box in the page is the same! So, we split and just put half the boxes in each child. */
	if ( all_entries_equal )
	{
		POSTGIS_DEBUG(4, "[GIST] picksplit finds all entries equal!");
		geography_gist_picksplit_fallback(entryvec, v);
		PG_RETURN_POINTER(v);
	}

	/* Initialize memory structures. */
	nbytes = (max_offset + 2) * sizeof(OffsetNumber);
	ndims_pageunion = GIDX_NDIMS(box_pageunion);
	POSTGIS_DEBUGF(4, "[GIST] ndims_pageunion == %d", ndims_pageunion);
	pos = palloc(2*ndims_pageunion * sizeof(int));
	list = palloc(2*ndims_pageunion * sizeof(OffsetNumber*));
	box_union = palloc(2*ndims_pageunion * sizeof(GIDX*));
	for ( d = 0; d < ndims_pageunion; d++ )
	{
		list[BELOW(d)] = (OffsetNumber*) palloc(nbytes);
		list[ABOVE(d)] = (OffsetNumber*) palloc(nbytes);
		box_union[BELOW(d)] = gidx_new(ndims_pageunion);
		box_union[ABOVE(d)] = gidx_new(ndims_pageunion);
		pos[BELOW(d)] = 0;
		pos[ABOVE(d)] = 0;
	}

	/*
	** Assign each entry in the node to the volume partitions it belongs to,
	** such as "above the x/y plane, left of the y/z plane, below the x/z plane".
	** Each entry thereby ends up in three of the six partitions.
	*/
	POSTGIS_DEBUG(4, "[GIST] 'picksplit' calculating best split axis");
	for ( i = FirstOffsetNumber; i <= max_offset; i = OffsetNumberNext(i) )
	{
		box_current = (GIDX*) DatumGetPointer(entryvec->vector[i].key);

		for ( d = 0; d < ndims_pageunion; d++ )
		{
			if ( GIDX_GET_MIN(box_current,d)-GIDX_GET_MIN(box_pageunion,d) < GIDX_GET_MAX(box_pageunion,d)-GIDX_GET_MAX(box_current,d) )
			{
				geography_gist_picksplit_addlist(list[BELOW(d)], &(box_union[BELOW(d)]), box_current, &(pos[BELOW(d)]), i);
			}
			else
			{
				geography_gist_picksplit_addlist(list[ABOVE(d)], &(box_union[ABOVE(d)]), box_current, &(pos[ABOVE(d)]), i);
			}

		}

	}

	/*
	** "Bad disposition", too many entries fell into one octant of the space, so no matter which
	** plane we choose to split on, we're going to end up with a mostly full node. Where the
	** data is pretty homogeneous (lots of duplicates) entries that are equidistant from the
	** sides of the page union box can occasionally all end up in one place, leading
	** to this condition.
	*/
	if ( geography_gist_picksplit_badratios(pos,ndims_pageunion) == TRUE )
	{
		/*
		** Instead we split on center points and see if we do better.
		** First calculate the average center point for each axis.
		*/
		double *avgCenter = palloc(ndims_pageunion * sizeof(double));

		for ( d = 0; d < ndims_pageunion; d++ )
		{
			avgCenter[d] = 0.0;
		}

		POSTGIS_DEBUG(4, "[GIST] picksplit can't find good split axis, trying center point method");

		for ( i = FirstOffsetNumber; i <= max_offset; i = OffsetNumberNext(i) )
		{
			box_current = (GIDX*) DatumGetPointer(entryvec->vector[i].key);
			for ( d = 0; d < ndims_pageunion; d++ )
			{
				avgCenter[d] += (GIDX_GET_MAX(box_current,d) + GIDX_GET_MIN(box_current,d)) / 2.0;
			}
		}
		for ( d = 0; d < ndims_pageunion; d++ )
		{
			avgCenter[d] /= max_offset;
			pos[BELOW(d)] = pos[ABOVE(d)] = 0; /* Re-initialize our counters. */
			POSTGIS_DEBUGF(4, "[GIST] picksplit average center point[%d] = %.12g", d, avgCenter[d]);
		}

		/* For each of our entries... */
		for ( i = FirstOffsetNumber; i <= max_offset; i = OffsetNumberNext(i) )
		{
			double center;
			box_current = (GIDX*) DatumGetPointer(entryvec->vector[i].key);

			for ( d = 0; d < ndims_pageunion; d++ )
			{
				center = (GIDX_GET_MIN(box_current,d)+GIDX_GET_MAX(box_current,d))/2.0;
				if ( center < avgCenter[d] )
					geography_gist_picksplit_addlist(list[BELOW(d)], &(box_union[BELOW(d)]), box_current, &(pos[BELOW(d)]), i);
				else if ( FPeq(center, avgCenter[d]) )
					if ( pos[BELOW(d)] > pos[ABOVE(d)] )
						geography_gist_picksplit_addlist(list[ABOVE(d)], &(box_union[ABOVE(d)]), box_current, &(pos[ABOVE(d)]), i);
					else
						geography_gist_picksplit_addlist(list[BELOW(d)], &(box_union[BELOW(d)]), box_current, &(pos[BELOW(d)]), i);
				else
					geography_gist_picksplit_addlist(list[ABOVE(d)], &(box_union[ABOVE(d)]), box_current, &(pos[ABOVE(d)]), i);
			}

		}

		/* Do we have a good disposition now? If not, screw it, just cut the node in half. */
		if ( geography_gist_picksplit_badratios(pos,ndims_pageunion) == TRUE )
		{
			POSTGIS_DEBUG(4, "[GIST] picksplit still cannot find a good split! just cutting the node in half");
			geography_gist_picksplit_fallback(entryvec, v);
			PG_RETURN_POINTER(v);
		}

	}

	/*
	** Now, what splitting plane gives us the most even ratio of
	** entries in our child pages? Since each split region has been apportioned entries
	** against the same number of total entries, the axis that has the smallest maximum
	** number of entries in its regions is the most evenly distributed.
	** TODO: what if the distributions are equal in two or more axes?
	*/
	for ( d = 0; d < ndims_pageunion; d++ )
	{
		int posd = Max(pos[ABOVE(d)],pos[BELOW(d)]);
		if ( posd > posmax )
		{
			direction = d;
			posmax = posd;
		}
	}
	if ( direction == -1 || posmax == -1 )
	{
		/* ERROR OUT HERE */
		elog(ERROR, "Error in building split, unable to determine split direction.");
	}

	POSTGIS_DEBUGF(3, "[GIST] 'picksplit' splitting on axis %d", direction);

	geography_gist_picksplit_constructsplit(v, list[BELOW(direction)],
	                                        pos[BELOW(direction)],
	                                        &(box_union[BELOW(direction)]),
	                                        list[ABOVE(direction)],
	                                        pos[ABOVE(direction)],
	                                        &(box_union[ABOVE(direction)]) );

	POSTGIS_DEBUGF(4, "[GIST] spl_ldatum: %s", gidx_to_string((GIDX*)v->spl_ldatum));
	POSTGIS_DEBUGF(4, "[GIST] spl_rdatum: %s", gidx_to_string((GIDX*)v->spl_rdatum));

	POSTGIS_DEBUGF(4, "[GIST] axis %d: parent range (%.12g, %.12g) left range (%.12g, %.12g), right range (%.12g, %.12g)",
	               direction,
	               GIDX_GET_MIN(box_pageunion, direction), GIDX_GET_MAX(box_pageunion, direction),
	               GIDX_GET_MIN((GIDX*)v->spl_ldatum, direction), GIDX_GET_MAX((GIDX*)v->spl_ldatum, direction),
	               GIDX_GET_MIN((GIDX*)v->spl_rdatum, direction), GIDX_GET_MAX((GIDX*)v->spl_rdatum, direction) );

	PG_RETURN_POINTER(v);

}