GRASS GIS 7 Programmer's Manual
7.9.dev(2021)-e5379bbd7
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by GRASS Development Team (https://grass.osgeo.org)
Reduced topology: each boundary is attached to one area only, i.e. smoothing, simplification, removing small areas etc. will not work properly for adjacent areas or areas within areas.
Full topology is only available for native GRASS vectors or can only be built after all polygons are converted to areas and cleaned as done by v.in.ogr
.
Frmt is a plain text file which contains basic information about external format of linked vector map. Each line contains key, value pairs separated by comma.
OGR specific format is described by:
Example:
FORMAT: ogr DSN: /path/to/shapefiles LAYER: cities
OGR layer can be linked via v.external
command. When linking OGR layer pseudo-topology ('topo') is built including spatial index file ('sidx') and category index file ('cidx'). Additionally also feature index file (see Fidx file format specification) is created.
Note: finfo
is an instance of Format_info structure.
Name | Type | Number | Description |
Version_Major | C | 1 | file version (major) |
Version_Minor | C | 1 | file version (minor) |
Back_Major | C | 1 | supported from GRASS version (major) |
Back_Minor | C | 1 | supported from GRASS version (minor) |
byte_order | C | 1 | little or big endian flag; files are written in machine native order but files in both little and big endian order may be readl; zero for little endian |
length | L | 1 | header size |
fInfo.ogr.offset_num | I | 1 | number of records |
fInfo.ogr.offset | I | offset_num | offsets |