## NAME

t.vect.export - Exports a space time vector dataset as GRASS GIS specific archive file.

## KEYWORDS

temporal, export, vector, time

## SYNOPSIS

t.vect.export
t.vect.export --help
t.vect.export input=name output=name [directory=name] [compression=string] [format=string] [where=sql_query] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

### Flags:

--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=name [required]
  Name of the input space time vector dataset
output=name [required]
  Name of a space time vector dataset archive
directory=name
  Path to the work directory, default is /tmp
  Default: /tmp
compression=string
  Compression method of the tar archive
  Options: no, gzip, bzip2
  Default: bzip2
format=string
  The export format of a single vector map
  Supported are GML and GPKG via v.out.ogr and the GRASS package format of v.pack
  Options: GML, GPKG, pack
  Default: GML
where=sql_query
  WHERE conditions of SQL statement without 'where' keyword used in the temporal GIS framework
  Example: start_time > '2001-01-01 12:30:00'

## DESCRIPTION

t.vect.export exports a space time vector dataset (stvds) to a tar archive as either GML (using v.out.ogr) or GRASS pack files. In addition to the pack or GML files, several metadata files are also created in the archive that describe the temporal layout. All time stamps are stored in the file "list.txt", for each map one row. The name of the map, the start time and the end time are written. In case of a time instance, the start time is equal to the end time. The "init.txt" file stores the temporal type, the number of maps, the chosen export format and some other metadata. The "proj.txt" file stores the projection information as a proj4 string of the location the space time vector dataset was exported from. The file "readme.txt" describes the file format. The output of v.info for each vector map in the space time dataset is stored in "metadata.txt".

The tar archive can be compressed using the compress option. Gzip and bzip2 (default) are available. A where option can be specified, to export only a subset of the space time dataset. Archives exported with t.vect.export can be imported with t.vect.import.

## NOTES

The name of output file has to carry the suffix of the archive type, the following suffix can be used:

- .tar in the case of compress=no
- .tar.bzip2 in the case of compress=bzip2
- .tar.gzip in the case of compress=gzip

## EXAMPLE

In this example, five vector maps are created and registered in a single space time vector dataset named random_locations. Each vector map represents random locations within the boundary of the state taken at 1 month intervals.

    t.vect.export input=shoreline output=shoreline_nc.tar.bzip2

    tar xvfj shoreline_nc.tar.bzip2
    shoreline_1849_1873.xml
    shoreline_1849_1873.xsd
    shoreline_1925_1946.xml
    shoreline_1925_1946.xsd
    shoreline_1970_1988.xml
    shoreline_1970_1988.xsd
    shoreline_1997.xml
    shoreline_1997.xsd
    shoreline_1998.xml
    shoreline_1998.xsd
    shoreline_2003.xml
    shoreline_2003.xsd
    shoreline_2004.xml
    shoreline_2004.xsd
    shoreline_2009.xml
    shoreline_2009.xsd
    list.txt
    proj.txt
    init.txt
    readme.txt
    metadata.txt

    cat init.txt
    stds_type=stvds
    format=GML
    temporal_type=relative
    semantic_type=mean
    relative_time_unit=years
    number_of_maps=8
    north=1039175.31479
    south=9403.301982
    east=3052352.00337
    west=651481.84739

    cat proj.txt
    +proj=lcc
    +lat_1=36.16666666666666
    +lat_2=34.33333333333334
    +lat_0=33.75
    +lon_0=-79
    +x_0=609601.22
    +y_0=0
    +no_defs
    +a=6378137
    +rf=298.257222101
    +towgs84=0.000,0.000,0.000
    +to_meter=1

    cat list.txt
    shoreline_1849_1873|1849|1873
    shoreline_1925_1946|1925|1946
    shoreline_1970_1988|1970|1988
    shoreline_1997|1997|1997
    shoreline_1998|1998|1998
    shoreline_2003|2003|2003
    shoreline_2004|2004|2004
    shoreline_2009|2009|2009

    cat readme.txt
    This space time vector dataset was exported with t.vect.export of GRASS GIS 7

    Files:
           *.xml  -- Vector GML files
         proj.txt -- Projection information in PROJ format
         init.txt -- GRASS GIS space time vector dataset information
         list.txt -- Time series file, lists all maps by name with interval
                     time stamps in ISO-Format. Field separator is |
     metadata.txt -- The output of t.info
       readme.txt -- This file

## SEE ALSO

t.vect.import, t.create, t.info, v.out.ogr, v.unpack, t.rast.export

## AUTHOR

Sören Gebbert, Thünen Institute of Climate-Smart Agriculture

## SOURCE CODE

Available at: t.vect.export source code (history)

Accessed: Thursday Nov 14 00:06:02 2024

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