NAME

       v.import  - Imports vector data into a GRASS vector map using OGR library and reprojects on the fly.

KEYWORDS

       vector, import, projection

SYNOPSIS

       v.import
       v.import --help
       v.import    [-flo]    input=string     [layer=string[,string,...]]      [output=name]     [extent=string]
       [encoding=string]    [snap=float]    [epsg=integer]    [datum_trans=integer]    [--overwrite]    [--help]
       [--verbose]  [--quiet]  [--ui]

   Flags:
       -f
           List supported OGR formats and exit

       -l
           List available OGR layers in data source and exit

       -o
           Override projection check (use current project’s CRS)
           Assume that the dataset has the same coordinate reference system (CRS) as the current project

       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       input=string [required]
           Name of OGR datasource to be imported

       layer=string[,string,...]
           OGR layer name. If not given, all available layers are imported

       output=name
           Name for output vector map (default: input)

       extent=string
           Output vector map extent
           Options: input, region
           Default: input
           input: extent of input map
           region: extent of current region

       encoding=string
           Encoding value for attribute data

       snap=float
           Snapping threshold for boundaries (map units)
           A suitable threshold is estimated during import
           Default: -1

       epsg=integer
           EPSG projection code
           Options: 1-1000000

       datum_trans=integer
           Index number of datum transform parameters
           -1 to list available datum transform parameters
           Options: -1-100

DESCRIPTION

       v.import  imports  vector  data from files and database connections supported by the OGR library into the
       current project (previously called location) and mapset. If the coordinate reference system (CRS) of  the
       input  does  not match the CRS of the project, the input is reprojected into the current project. In case
       that the CRS of the input map does match the CRS of the project, the input is imported directly.

   Supported Vector Formats
       v.import uses the OGR library which supports  various  vector  data  formats  including  ESRI  Shapefile,
       Mapinfo  File,  UK  .NTF,  SDTS,  TIGER,  IHO  S-57  (ENC), DGN, GML, GPX, AVCBin, REC, Memory, OGDI, and
       PostgreSQL, depending on the local OGR installation.  For details see the OGR web site. The  OGR  (Simple
       Features Library) is part of the GDAL library, hence GDAL needs to be installed to use v.import.

       The list of actually supported formats can be printed by -f flag.

NOTES

       v.import  checks  the  CRS metadata of the dataset to be imported against that of the current project. If
       not identical a related error message is shown.
       To override this CRS check (i.e. to use current project’s CRS) by assuming that the dataset has the  same
       CRS  as  the  current project the -o flag can be used. This is also useful when geodata to be imported do
       not contain any CRS metadata at all. The user must be sure that the CRS is identical in  order  to  avoid
       introducing data errors.

   Topology cleaning
       When  importing  polygons,  non-topological  polygons  are  converted  to topological areas. If the input
       polygons contain errors (unexpected overlapping areas, small gaps between  polygons,  or  warnings  about
       being  unable  to  calculate  centroids),  the  import  might  need  to be repeated using a snap value as
       suggested in the output messages. The default value of snap=-1 means that no snapping will be done.

       The snap threshold  defines  the  maximal  distance  from  one  to  another  vertex  in  map  units  (for
       latitude-longitude  projects  in  degrees). If there is no other vertex within snap distance, no snapping
       will be done.  Note that a too large value can severely damage area topology, beyond repair.

       Post-processing:  Snapped  boundaries  may  need  to  be  cleaned   with   v.clean,   using   its   tools
       break,rmdupl,rmsa. For details, refer to the v.clean manual page.

EXAMPLE

       # import SHAPE file at full extent and reproject to current project CRS
       v.import input=research_area.shp output=research_area extent=input

SEE ALSO

        v.clean, v.in.lines, v.in.ogr, v.proj

AUTHORS

       Markus Metz
       Improvements: Martin Landa, Anna Petrasova

SOURCE CODE

       Available at: v.import source code (history)

       Accessed: Friday Apr 04 01:21:13 2025

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       © 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual

GRASS 8.4.1                                                                                     v.import(1grass)