GRASS GIS 7 Programmer's Manual
7.9.dev(2021)-e5379bbd7
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Data structure used for building pseudo-topology. More...
#include <dig_structs.h>
Data Fields | |
int * | array |
Offset list. More... | |
int | array_num |
Number of items in offset list. More... | |
int | array_alloc |
Space allocated for offset list. More... | |
Data structure used for building pseudo-topology.
See Vect__build_sfa() (Format_info_ogr and Format_info_pg) for implementation issues.
Definition at line 397 of file dig_structs.h.
int* Format_info_offset::array |
Offset list.
Array where feature/part info is stored for each feature in GRASS. This is not used for GV_CENTROID. Because one feature may contain more elements (geometry collection also recursively), offset for one line may be stored in more records. First record is FID, next records are part indexes if necessary.
Example 1:
Example 2: geometry collection FID '1' containing one point, one linestring and one polygon
Offset: idx offset note ---------------- 0 1 FID 1 0 first part (point) 2 1 FID 3 1 second part (linestring) 4 1 FID 5 2 third part (polygon) 6 0 first ring of polygon GRASS topology: line idx ----------------- 1 0 point 2 2 line 3 4 boundary 4 1 centroid read from topo (idx == FID) In PostGIS Topology mode the offset array is used for mapping nodes.
Definition at line 446 of file dig_structs.h.
Referenced by V1_delete_line_ogr(), V1_delete_line_pg(), Vect__free_offset(), Vect__load_map_nodes_pg(), Vect_build_ogr(), Vect_build_pg(), Vect_fidx_dump(), Vect_open_fidx(), and Vect_save_fidx().
int Format_info_offset::array_alloc |
Space allocated for offset list.
Definition at line 454 of file dig_structs.h.
Referenced by Vect__load_map_nodes_pg(), and Vect_open_fidx().
int Format_info_offset::array_num |
Number of items in offset list.
Definition at line 450 of file dig_structs.h.
Referenced by V1_delete_line_ogr(), V1_delete_line_pg(), Vect__load_map_nodes_pg(), Vect_fidx_dump(), Vect_open_fidx(), and Vect_save_fidx().