GRASS Programmer's Manual
6.4.2(2012)
|
00001 00002 /**************************************************************************** 00003 * MODULE: R-Tree library 00004 * 00005 * AUTHOR(S): Antonin Guttman - original code 00006 * Daniel Green (green@superliminal.com) - major clean-up 00007 * and implementation of bounding spheres 00008 * 00009 * PURPOSE: Multidimensional index 00010 * 00011 * COPYRIGHT: (C) 2001 by the GRASS Development Team 00012 * 00013 * This program is free software under the GNU General Public 00014 * License (>=v2). Read the file COPYING that comes with GRASS 00015 * for details. 00016 *****************************************************************************/ 00017 00018 #include <stdio.h> 00019 #include "index.h" 00020 00021 struct Rect rects[] = { 00022 {{0, 0, 0, 2, 2, 0}}, /* xmin, ymin, zmin, xmax, ymax, zmax (for 3 dimensional RTree) */ 00023 {{5, 5, 0, 7, 7, 0}}, 00024 {{8, 5, 0, 9, 6, 0}}, 00025 {{7, 1, 0, 9, 2, 0}} 00026 }; 00027 00028 00029 int nrects = sizeof(rects) / sizeof(rects[0]); 00030 struct Rect search_rect = { 00031 {6, 4, 0, 10, 6, 0} /* search will find above rects that this one overlaps */ 00032 }; 00033 00034 int MySearchCallback(int id, void *arg) 00035 { 00036 /* Note: -1 to make up for the +1 when data was inserted */ 00037 fprintf(stdout, "Hit data rect %d\n", id - 1); 00038 return 1; /* keep going */ 00039 } 00040 00041 int main() 00042 { 00043 struct Node *root = RTreeNewIndex(); 00044 int i, nhits; 00045 00046 fprintf(stdout, "nrects = %d\n", nrects); 00047 /* 00048 * Insert all the data rects. 00049 * Notes about the arguments: 00050 * parameter 1 is the rect being inserted, 00051 * parameter 2 is its ID. NOTE: *** ID MUST NEVER BE ZERO ***, hence the +1, 00052 * parameter 3 is the root of the tree. Note: its address is passed 00053 * because it can change as a result of this call, therefore no other parts 00054 * of this code should stash its address since it could change undernieth. 00055 * parameter 4 is always zero which means to add from the root. 00056 */ 00057 for (i = 0; i < nrects; i++) 00058 RTreeInsertRect(&rects[i], i + 1, &root, 0); /* i+1 is rect ID. Note: root can change */ 00059 nhits = RTreeSearch(root, &search_rect, MySearchCallback, 0); 00060 fprintf(stdout, "Search resulted in %d hits\n", nhits); 00061 00062 return 0; 00063 }