t.vect.export(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

🌸 NAME 🌸

t.vect.export — bestie, she exports a space time vector dataset as GRASS GIS specific archive file. that's the whole job, no side quests, no drama. 💅

(and yes, you're reading the GRASS GIS User's Manual right now — welcome, you're in the right place 🦋)

🔑 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 — let the output files steamroll any existing files that get in the way. no survivors, no hesitation. 😤
  • --help — prints the usage summary, aka the "wait what were the flags again" button.
  • --verbose — verbose module output. she's chatty, she's telling you everything. 💬
  • --quiet — quiet module output. shhh. 🤫
  • --ui — force-launches the GUI dialog. main character energy, but in a window. 👑

🎀 Parameters:

  • input=name [required] — name of the input space time vector dataset. you must give her this.
  • output=name [required] — name of a space time vector dataset archive. also mandatory, no skipping.
  • 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 💖

okay so t.vect.export takes a space time vector dataset (stvds, if you wanna be cute about it) and yeets it into a tar archive, either as GML (using v.out.ogr) or as GRASS pack files. 🫶

but here's the part everyone forgets: it's not just the pack or GML files, bestie. several metadata files get created in the archive too, and they describe the temporal layout. let's go through them because this is genuinely the good part:

  • all time stamps get stored in list.txt, one row per map. the name of the map, the start time, and the end time get written. in case of a time instance, the start time is equal to the end time (yes, same, twins, iconic). 🕐
  • 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 coordinate reference system info as a proj4 string of the project 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 (which is the default, fyi) are available. a where option can be specified to export only a subset of the space time dataset, which is lowkey the best way to not ship your entire life to someone. 🎀

archives exported with t.vect.export can be imported with t.vect.import. that's the round trip, periodt.

📝 NOTES 📝

the name of the output file has to carry the suffix of the archive type. here's which suffix goes with which compression, no guessing:

  • .tar in the case of compress=no
  • .tar.bzip2 in the case of compress=bzip2
  • .tar.gzip in the case of compress=gzip
ngl, if you get the suffix wrong she will not be happy with you. suffix and compression have to match, it's giving matching outfits. 💀

🌈 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

and boom, the archive unpacks into this absolute spread:

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

peep the init.txt, it's got the whole vibe documented:

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

then the projection info, fresh out of proj.txt:

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

and the time series file, list.txt, name plus start and end, pipe-separated:

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

and finally the readme.txt, which literally explains itself, we love a self-aware file:

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: Saturday Jan 17 05:41:54 2026

Main index | Temporal index | Topics index | Keywords index | Graphical index | Full index

© 2003-2025 GRASS Development Team, GRASS GIS 8.4.2 Reference Manual

and that's the whole page bestie, you made it to the bottom 🥳 this was t.vect.export(1) from GRASS 8.4.2, and the source was last accessed Saturday Jan 17 05:41:54 2026 — go export something, she's waiting for you. 💜✨

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