/******************************************************************************
* $Id$
*
* Project: Shapelib
* Purpose: Implementation of quadtree building and searching functions.
* Author: Frank Warmerdam, warmerdam@pobox.com
*
******************************************************************************
* Copyright (c) 1999, Frank Warmerdam
*
* This software is available under the following "MIT Style" license,
* or at the option of the licensee under the LGPL (see LICENSE.LGPL). This
* option is discussed in more detail in shapelib.html.
*
* --
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
******************************************************************************
*
* $Log$
* Revision 1.1 2005/08/14 21:40:30 jswhit
* inclusion of pyshapelib
*
* Revision 1.2 2003/10/02 15:15:16 bh
*
* Update to shapelib 1.2.10
*
* Revision 1.9 2003/01/28 15:53:41 warmerda
* Avoid build warnings.
*
* Revision 1.8 2002/05/07 13:07:45 warmerda
* use qsort() - patch from Bernhard Herzog
*
* Revision 1.7 2002/01/15 14:36:07 warmerda
* updated email address
*
* Revision 1.6 2001/05/23 13:36:52 warmerda
* added use of SHPAPI_CALL
*
* Revision 1.5 1999/11/05 14:12:05 warmerda
* updated license terms
*
* Revision 1.4 1999/06/02 18:24:21 warmerda
* added trimming code
*
* Revision 1.3 1999/06/02 17:56:12 warmerda
* added quad'' subnode support for trees
*
* Revision 1.2 1999/05/18 19:11:11 warmerda
* Added example searching capability
*
* Revision 1.1 1999/05/18 17:49:20 warmerda
* New
*
*/
static char rcsid[] =
"$Id$";
#include "shapefil.h"
#include <math.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#ifndef TRUE
# define TRUE 1
# define FALSE 0
#endif
/* -------------------------------------------------------------------- */
/* If the following is 0.5, nodes will be split in half. If it */
/* is 0.6 then each subnode will contain 60% of the parent */
/* node, with 20% representing overlap. This can be help to */
/* prevent small objects on a boundary from shifting too high */
/* up the tree. */
/* -------------------------------------------------------------------- */
#define SHP_SPLIT_RATIO 0.55
/************************************************************************/
/* SfRealloc() */
/* */
/* A realloc cover function that will access a NULL pointer as */
/* a valid input. */
/************************************************************************/
static void * SfRealloc( void * pMem, int nNewSize )
{
if( pMem == NULL )
return( (void *) malloc(nNewSize) );
else
return( (void *) realloc(pMem,nNewSize) );
}
/************************************************************************/
/* SHPTreeNodeInit() */
/* */
/* Initialize a tree node. */
/************************************************************************/
static SHPTreeNode *SHPTreeNodeCreate( double * padfBoundsMin,
double * padfBoundsMax )
{
SHPTreeNode *psTreeNode;
psTreeNode = (SHPTreeNode *) malloc(sizeof(SHPTreeNode));
psTreeNode->nShapeCount = 0;
psTreeNode->panShapeIds = NULL;
psTreeNode->papsShapeObj = NULL;
psTreeNode->nSubNodes = 0;
if( padfBoundsMin != NULL )
memcpy( psTreeNode->adfBoundsMin, padfBoundsMin, sizeof(double) * 4 );
if( padfBoundsMax != NULL )
memcpy( psTreeNode->adfBoundsMax, padfBoundsMax, sizeof(double) * 4 );
return psTreeNode;
}
/************************************************************************/
/* SHPCreateTree() */
/************************************************************************/
SHPTree SHPAPI_CALL1(*)
SHPCreateTree( SHPHandle hSHP, int nDimension, int nMaxDepth,
double *padfBoundsMin, double *padfBoundsMax )
{
SHPTree *psTree;
if( padfBoundsMin == NULL && hSHP == NULL )
return NULL;
/* -------------------------------------------------------------------- */
/* Allocate the tree object */
/* -------------------------------------------------------------------- */
psTree = (SHPTree *) malloc(sizeof(SHPTree));
psTree->hSHP = hSHP;
psTree->nMaxDepth = nMaxDepth;
psTree->nDimension = nDimension;
/* -------------------------------------------------------------------- */
/* If no max depth was defined, try to select a reasonable one */
/* that implies approximately 8 shapes per node. */
/* -------------------------------------------------------------------- */
if( psTree->nMaxDepth == 0 && hSHP != NULL )
{
int nMaxNodeCount = 1;
int nShapeCount;
SHPGetInfo( hSHP, &nShapeCount, NULL, NULL, NULL );
while( nMaxNodeCount*4 < nShapeCount )
{
psTree->nMaxDepth += 1;
nMaxNodeCount = nMaxNodeCount * 2;
}
}
/* -------------------------------------------------------------------- */
/* Allocate the root node. */
/* -------------------------------------------------------------------- */
psTree->psRoot = SHPTreeNodeCreate( padfBoundsMin, padfBoundsMax );
/* -------------------------------------------------------------------- */
/* Assign the bounds to the root node. If none are passed in, */
/* use the bounds of the provided file otherwise the create */
/* function will have already set the bounds. */
/* -------------------------------------------------------------------- */
if( padfBoundsMin == NULL )
{
SHPGetInfo( hSHP, NULL, NULL,
psTree->psRoot->adfBoundsMin,
psTree->psRoot->adfBoundsMax );
}
/* -------------------------------------------------------------------- */
/* If we have a file, insert all it's shapes into the tree. */
/* -------------------------------------------------------------------- */
if( hSHP != NULL )
{
int iShape, nShapeCount;
SHPGetInfo( hSHP, &nShapeCount, NULL, NULL, NULL );
for( iShape = 0; iShape < nShapeCount; iShape++ )
{
SHPObject *psShape;
psShape = SHPReadObject( hSHP, iShape );
SHPTreeAddShapeId( psTree, psShape );
SHPDestroyObject( psShape );
}
}
return psTree;
}
/************************************************************************/
/* SHPDestroyTreeNode() */
/************************************************************************/
static void SHPDestroyTreeNode( SHPTreeNode * psTreeNode )
{
int i;
for( i = 0; i < psTreeNode->nSubNodes; i++ )
{
if( psTreeNode->apsSubNode[i] != NULL )
SHPDestroyTreeNode( psTreeNode->apsSubNode[i] );
}
if( psTreeNode->panShapeIds != NULL )
free( psTreeNode->panShapeIds );
if( psTreeNode->papsShapeObj != NULL )
{
for( i = 0; i < psTreeNode->nShapeCount; i++ )
{
if( psTreeNode->papsShapeObj[i] != NULL )
SHPDestroyObject( psTreeNode->papsShapeObj[i] );
}
free( psTreeNode->papsShapeObj );
}
free( psTreeNode );
}
/************************************************************************/
/* SHPDestroyTree() */
/************************************************************************/
void SHPAPI_CALL
SHPDestroyTree( SHPTree * psTree )
{
SHPDestroyTreeNode( psTree->psRoot );
free( psTree );
}
/************************************************************************/
/* SHPCheckBoundsOverlap() */
/* */
/* Do the given boxes overlap at all? */
/************************************************************************/
int SHPAPI_CALL
SHPCheckBoundsOverlap( double * padfBox1Min, double * padfBox1Max,
double * padfBox2Min, double * padfBox2Max,
int nDimension )
{
int iDim;
for( iDim = 0; iDim < nDimension; iDim++ )
{
if( padfBox2Max[iDim] < padfBox1Min[iDim] )
return FALSE;
if( padfBox1Max[iDim] < padfBox2Min[iDim] )
return FALSE;
}
return TRUE;
}
/************************************************************************/
/* SHPCheckObjectContained() */
/* */
/* Does the given shape fit within the indicated extents? */
/************************************************************************/
static int SHPCheckObjectContained( SHPObject * psObject, int nDimension,
double * padfBoundsMin, double * padfBoundsMax )
{
if( psObject->dfXMin < padfBoundsMin[0]
|| psObject->dfXMax > padfBoundsMax[0] )
return FALSE;
if( psObject->dfYMin < padfBoundsMin[1]
|| psObject->dfYMax > padfBoundsMax[1] )
return FALSE;
if( nDimension == 2 )
return TRUE;
if( psObject->dfZMin < padfBoundsMin[2]
|| psObject->dfZMax < padfBoundsMax[2] )
return FALSE;
if( nDimension == 3 )
return TRUE;
if( psObject->dfMMin < padfBoundsMin[3]
|| psObject->dfMMax < padfBoundsMax[3] )
return FALSE;
return TRUE;
}
/************************************************************************/
/* SHPTreeSplitBounds() */
/* */
/* Split a region into two subregion evenly, cutting along the */
/* longest dimension. */
/************************************************************************/
void SHPAPI_CALL
SHPTreeSplitBounds( double *padfBoundsMinIn, double *padfBoundsMaxIn,
double *padfBoundsMin1, double * padfBoundsMax1,
double *padfBoundsMin2, double * padfBoundsMax2 )
{
/* -------------------------------------------------------------------- */
/* The output bounds will be very similar to the input bounds, */
/* so just copy over to start. */
/* -------------------------------------------------------------------- */
memcpy( padfBoundsMin1, padfBoundsMinIn, sizeof(double) * 4 );
memcpy( padfBoundsMax1, padfBoundsMaxIn, sizeof(double) * 4 );
memcpy( padfBoundsMin2, padfBoundsMinIn, sizeof(double) * 4 );
memcpy( padfBoundsMax2, padfBoundsMaxIn, sizeof(double) * 4 );
/* -------------------------------------------------------------------- */
/* Split in X direction. */
/* -------------------------------------------------------------------- */
if( (padfBoundsMaxIn[0] - padfBoundsMinIn[0])
> (padfBoundsMaxIn[1] - padfBoundsMinIn[1]) )
{
double dfRange = padfBoundsMaxIn[0] - padfBoundsMinIn[0];
padfBoundsMax1[0] = padfBoundsMinIn[0] + dfRange * SHP_SPLIT_RATIO;
padfBoundsMin2[0] = padfBoundsMaxIn[0] - dfRange * SHP_SPLIT_RATIO;
}
/* -------------------------------------------------------------------- */
/* Otherwise split in Y direction. */
/* -------------------------------------------------------------------- */
else
{
double dfRange = padfBoundsMaxIn[1] - padfBoundsMinIn[1];
padfBoundsMax1[1] = padfBoundsMinIn[1] + dfRange * SHP_SPLIT_RATIO;
padfBoundsMin2[1] = padfBoundsMaxIn[1] - dfRange * SHP_SPLIT_RATIO;
}
}
/************************************************************************/
/* SHPTreeNodeAddShapeId() */
/************************************************************************/
static int
SHPTreeNodeAddShapeId( SHPTreeNode * psTreeNode, SHPObject * psObject,
int nMaxDepth, int nDimension )
{
int i;
/* -------------------------------------------------------------------- */
/* If there are subnodes, then consider wiether this object */
/* will fit in them. */
/* -------------------------------------------------------------------- */
if( nMaxDepth > 1 && psTreeNode->nSubNodes > 0 )
{
for( i = 0; i < psTreeNode->nSubNodes; i++ )
{
if( SHPCheckObjectContained(psObject, nDimension,
psTreeNode->apsSubNode[i]->adfBoundsMin,
psTreeNode->apsSubNode[i]->adfBoundsMax))
{
return SHPTreeNodeAddShapeId( psTreeNode->apsSubNode[i],
psObject, nMaxDepth-1,
nDimension );
}
}
}
/* -------------------------------------------------------------------- */
/* Otherwise, consider creating four subnodes if could fit into */
/* them, and adding to the appropriate subnode. */
/* -------------------------------------------------------------------- */
#if MAX_SUBNODE == 4
else if( nMaxDepth > 1 && psTreeNode->nSubNodes == 0 )
{
double adfBoundsMinH1[4], adfBoundsMaxH1[4];
double adfBoundsMinH2[4], adfBoundsMaxH2[4];
double adfBoundsMin1[4], adfBoundsMax1[4];
double adfBoundsMin2[4], adfBoundsMax2[4];
double adfBoundsMin3[4], adfBoundsMax3[4];
double adfBoundsMin4[4], adfBoundsMax4[4];
SHPTreeSplitBounds( psTreeNode->adfBoundsMin,
psTreeNode->adfBoundsMax,
adfBoundsMinH1, adfBoundsMaxH1,
adfBoundsMinH2, adfBoundsMaxH2 );
SHPTreeSplitBounds( adfBoundsMinH1, adfBoundsMaxH1,
adfBoundsMin1, adfBoundsMax1,
adfBoundsMin2, adfBoundsMax2 );
SHPTreeSplitBounds( adfBoundsMinH2, adfBoundsMaxH2,
adfBoundsMin3, adfBoundsMax3,
adfBoundsMin4, adfBoundsMax4 );
if( SHPCheckObjectContained(psObject, nDimension,
adfBoundsMin1, adfBoundsMax1)
|| SHPCheckObjectContained(psObject, nDimension,
adfBoundsMin2, adfBoundsMax2)
|| SHPCheckObjectContained(psObject, nDimension,
adfBoundsMin3, adfBoundsMax3)
|| SHPCheckObjectContained(psObject, nDimension,
adfBoundsMin4, adfBoundsMax4) )
{
psTreeNode->nSubNodes = 4;
psTreeNode->apsSubNode[0] = SHPTreeNodeCreate( adfBoundsMin1,
adfBoundsMax1 );
psTreeNode->apsSubNode[1] = SHPTreeNodeCreate( adfBoundsMin2,
adfBoundsMax2 );
psTreeNode->apsSubNode[2] = SHPTreeNodeCreate( adfBoundsMin3,
adfBoundsMax3 );
psTreeNode->apsSubNode[3] = SHPTreeNodeCreate( adfBoundsMin4,
adfBoundsMax4 );
/* recurse back on this node now that it has subnodes */
return( SHPTreeNodeAddShapeId( psTreeNode, psObject,
nMaxDepth, nDimension ) );
}
}
#endif /* MAX_SUBNODE == 4 */
/* -------------------------------------------------------------------- */
/* Otherwise, consider creating two subnodes if could fit into */
/* them, and adding to the appropriate subnode. */
/* -------------------------------------------------------------------- */
#if MAX_SUBNODE == 2
else if( nMaxDepth > 1 && psTreeNode->nSubNodes == 0 )
{
double adfBoundsMin1[4], adfBoundsMax1[4];
double adfBoundsMin2[4], adfBoundsMax2[4];
SHPTreeSplitBounds( psTreeNode->adfBoundsMin, psTreeNode->adfBoundsMax,
adfBoundsMin1, adfBoundsMax1,
adfBoundsMin2, adfBoundsMax2 );
if( SHPCheckObjectContained(psObject, nDimension,
adfBoundsMin1, adfBoundsMax1))
{
psTreeNode->nSubNodes = 2;
psTreeNode->apsSubNode[0] = SHPTreeNodeCreate( adfBoundsMin1,
adfBoundsMax1 );
psTreeNode->apsSubNode[1] = SHPTreeNodeCreate( adfBoundsMin2,
adfBoundsMax2 );
return( SHPTreeNodeAddShapeId( psTreeNode->apsSubNode[0], psObject,
nMaxDepth - 1, nDimension ) );
}
else if( SHPCheckObjectContained(psObject, nDimension,
adfBoundsMin2, adfBoundsMax2) )
{
psTreeNode->nSubNodes = 2;
psTreeNode->apsSubNode[0] = SHPTreeNodeCreate( adfBoundsMin1,
adfBoundsMax1 );
psTreeNode->apsSubNode[1] = SHPTreeNodeCreate( adfBoundsMin2,
adfBoundsMax2 );
return( SHPTreeNodeAddShapeId( psTreeNode->apsSubNode[1], psObject,
nMaxDepth - 1, nDimension ) );
}
}
#endif /* MAX_SUBNODE == 2 */
/* -------------------------------------------------------------------- */
/* If none of that worked, just add it to this nodes list. */
/* -------------------------------------------------------------------- */
psTreeNode->nShapeCount++;
psTreeNode->panShapeIds =
SfRealloc( psTreeNode->panShapeIds,
sizeof(int) * psTreeNode->nShapeCount );
psTreeNode->panShapeIds[psTreeNode->nShapeCount-1] = psObject->nShapeId;
if( psTreeNode->papsShapeObj != NULL )
{
psTreeNode->papsShapeObj =
SfRealloc( psTreeNode->papsShapeObj,
sizeof(void *) * psTreeNode->nShapeCount );
psTreeNode->papsShapeObj[psTreeNode->nShapeCount-1] = NULL;
}
return TRUE;
}
/************************************************************************/
/* SHPTreeAddShapeId() */
/* */
/* Add a shape to the tree, but don't keep a pointer to the */
/* object data, just keep the shapeid. */
/************************************************************************/
int SHPAPI_CALL
SHPTreeAddShapeId( SHPTree * psTree, SHPObject * psObject )
{
return( SHPTreeNodeAddShapeId( psTree->psRoot, psObject,
psTree->nMaxDepth, psTree->nDimension ) );
}
/************************************************************************/
/* SHPTreeCollectShapesIds() */
/* */
/* Work function implementing SHPTreeFindLikelyShapes() on a */
/* tree node by tree node basis. */
/************************************************************************/
void SHPAPI_CALL
SHPTreeCollectShapeIds( SHPTree *hTree, SHPTreeNode * psTreeNode,
double * padfBoundsMin, double * padfBoundsMax,
int * pnShapeCount, int * pnMaxShapes,
int ** ppanShapeList )
{
int i;
/* -------------------------------------------------------------------- */
/* Does this node overlap the area of interest at all? If not, */
/* return without adding to the list at all. */
/* -------------------------------------------------------------------- */
if( !SHPCheckBoundsOverlap( psTreeNode->adfBoundsMin,
psTreeNode->adfBoundsMax,
padfBoundsMin,
padfBoundsMax,
hTree->nDimension ) )
return;
/* -------------------------------------------------------------------- */
/* Grow the list to hold the shapes on this node. */
/* -------------------------------------------------------------------- */
if( *pnShapeCount + psTreeNode->nShapeCount > *pnMaxShapes )
{
*pnMaxShapes = (*pnShapeCount + psTreeNode->nShapeCount) * 2 + 20;
*ppanShapeList = (int *)
SfRealloc(*ppanShapeList,sizeof(int) * *pnMaxShapes);
}
/* -------------------------------------------------------------------- */
/* Add the local nodes shapeids to the list. */
/* -------------------------------------------------------------------- */
for( i = 0; i < psTreeNode->nShapeCount; i++ )
{
(*ppanShapeList)[(*pnShapeCount)++] = psTreeNode->panShapeIds[i];
}
/* -------------------------------------------------------------------- */
/* Recurse to subnodes if they exist. */
/* -------------------------------------------------------------------- */
for( i = 0; i < psTreeNode->nSubNodes; i++ )
{
if( psTreeNode->apsSubNode[i] != NULL )
SHPTreeCollectShapeIds( hTree, psTreeNode->apsSubNode[i],
padfBoundsMin, padfBoundsMax,
pnShapeCount, pnMaxShapes,
ppanShapeList );
}
}
/************************************************************************/
/* SHPTreeFindLikelyShapes() */
/* */
/* Find all shapes within tree nodes for which the tree node */
/* bounding box overlaps the search box. The return value is */
/* an array of shapeids terminated by a -1. The shapeids will */
/* be in order, as hopefully this will result in faster (more */
/* sequential) reading from the file. */
/************************************************************************/
/* helper for qsort */
static int
compare_ints( const void * a, const void * b)
{
return (*(int*)a) - (*(int*)b);
}
int SHPAPI_CALL1(*)
SHPTreeFindLikelyShapes( SHPTree * hTree,
double * padfBoundsMin, double * padfBoundsMax,
int * pnShapeCount )
{
int *panShapeList=NULL, nMaxShapes = 0;
/* -------------------------------------------------------------------- */
/* Perform the search by recursive descent. */
/* -------------------------------------------------------------------- */
*pnShapeCount = 0;
SHPTreeCollectShapeIds( hTree, hTree->psRoot,
padfBoundsMin, padfBoundsMax,
pnShapeCount, &nMaxShapes,
&panShapeList );
/* -------------------------------------------------------------------- */
/* Sort the id array */
/* -------------------------------------------------------------------- */
qsort(panShapeList, *pnShapeCount, sizeof(int), compare_ints);
return panShapeList;
}
/************************************************************************/
/* SHPTreeNodeTrim() */
/* */
/* This is the recurve version of SHPTreeTrimExtraNodes() that */
/* walks the tree cleaning it up. */
/************************************************************************/
static int SHPTreeNodeTrim( SHPTreeNode * psTreeNode )
{
int i;
/* -------------------------------------------------------------------- */
/* Trim subtrees, and free subnodes that come back empty. */
/* -------------------------------------------------------------------- */
for( i = 0; i < psTreeNode->nSubNodes; i++ )
{
if( SHPTreeNodeTrim( psTreeNode->apsSubNode[i] ) )
{
SHPDestroyTreeNode( psTreeNode->apsSubNode[i] );
psTreeNode->apsSubNode[i] =
psTreeNode->apsSubNode[psTreeNode->nSubNodes-1];
psTreeNode->nSubNodes--;
i--; /* process the new occupant of this subnode entry */
}
}
/* -------------------------------------------------------------------- */
/* We should be trimmed if we have no subnodes, and no shapes. */
/* -------------------------------------------------------------------- */
return( psTreeNode->nSubNodes == 0 && psTreeNode->nShapeCount == 0 );
}
/************************************************************************/
/* SHPTreeTrimExtraNodes() */
/* */
/* Trim empty nodes from the tree. Note that we never trim an */
/* empty root node. */
/************************************************************************/
void SHPAPI_CALL
SHPTreeTrimExtraNodes( SHPTree * hTree )
{
SHPTreeNodeTrim( hTree->psRoot );
}
