GRASS GIS 8 Programmer's Manual
8.5.0dev(2024)6fb030f8d8

Vector library  graph manipulation. More...
#include <stdlib.h>
#include <string.h>
#include <grass/dbmi.h>
#include <grass/vector.h>
#include <grass/glocale.h>
Go to the source code of this file.
Functions  
void  Vect_graph_init (dglGraph_s *graph, int nodes_costs) 
Initialize graph structure. More...  
void  Vect_graph_build (dglGraph_s *graph) 
Build network graph. More...  
void  Vect_graph_add_edge (dglGraph_s *graph, int from, int to, double costs, int id) 
Add edge to graph. More...  
void  Vect_graph_set_node_costs (dglGraph_s *graph, int node, double costs) 
Set node costs. More...  
int  Vect_graph_shortest_path (dglGraph_s *graph, int from, int to, struct ilist *List, double *cost) 
Find shortest path. More...  
Vector library  graph manipulation.
Higher level functions for reading/writing/manipulating vectors.
(C) 20012009 by the GRASS Development Team
This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.
Definition in file vector/Vlib/graph.c.
void Vect_graph_add_edge  (  dglGraph_s *  graph, 
int  from,  
int  to,  
double  costs,  
int  id  
) 
Add edge to graph.
Internal format for edge costs is integer, costs are multiplied before conversion to int by 1000. Costs 1 for infinity i.e. arc or node is closed and cannot be traversed.
graph  pointer to graph structure 
from  from node 
to  to node 
costs  costs value 
id  edge id 
Definition at line 124 of file vector/Vlib/graph.c.
References _, dglAddEdge(), G_debug(), and G_fatal_error().
void Vect_graph_build  (  dglGraph_s *  graph  ) 
Build network graph.
Internal format for edge costs is integer, costs are multiplied before conversion to int by 1000. Costs 1 for infinity i.e. arc or node is closed and cannot be traversed.
graph  pointer to graph structure 
Definition at line 98 of file vector/Vlib/graph.c.
References _, dglFlatten(), G_debug(), and G_fatal_error().
void Vect_graph_init  (  dglGraph_s *  graph, 
int  nodes_costs  
) 
Initialize graph structure.
graph  pointer to graph structure 
nodes_costs  use node costs 
Definition at line 72 of file vector/Vlib/graph.c.
References dglInitialize(), and G_debug().
void Vect_graph_set_node_costs  (  dglGraph_s *  graph, 
int  node,  
double  costs  
) 
Set node costs.
Internal format for edge costs is integer, costs are multiplied before conversion to int by 1000. Costs 1 for infinity i.e. arc or node is closed and cannot be traversed.
graph  pointer to graph structure 
node  node id 
costs  costs value 
Definition at line 154 of file vector/Vlib/graph.c.
References dglGetNode(), dglNodeSet_Attr(), and G_debug().
int Vect_graph_shortest_path  (  dglGraph_s *  graph, 
int  from,  
int  to,  
struct ilist *  List,  
double *  cost  
) 
Find shortest path.
Costs for 'from' and 'to' nodes are not considered (SP found even if 'from' or 'to' are 'closed' (costs = 1) and costs of these nodes are not added to SP costs result.
graph  pointer to graph structure 
from  from node 
to  to node 
List  list of line ids 
cost  costs value 
Definition at line 183 of file vector/Vlib/graph.c.