## 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.

## 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 xvfj shoreline_nc
    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.4 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

Last changed: $Date: 2015-10-06 17:26:07 +0200 (Tue, 06 Oct 2015) $