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- <!-- meta page description: Temporal data processing in GRASS GIS -->
- <!-- meta page index: temporal -->
- The temporal enabled GRASS introduces three new datatypes that
- are designed to handle time series data:
- <ul>
- <li> <em>Space time raster datasets</em> (strds) are designed to manage
- raster map time series. Modules that process strds have the naming
- prefix <em>t.rast</em>.
- <li> <em>Space time 3D raster datasets</em> (str3ds) are designed to
- manage 3D raster map time series. Modules that process str3ds have the
- naming prefix <em>t.rast3d</em>.
- <li> <em>Space time vector datasets</em> (stvds) are designed to manage
- vector map time series. Modules that process stvds have the naming
- prefix <em>t.vect</em>.
- </ul>
- These new data types can be managed, analyzed and processed with temporal modules that
- are based on the GRASS GIS temporal framework.
- <h3>Temporal data management in general</h3>
- Space time datasets are stored in a temporal database. SQLite3 or
- PostgreSQL are supported as SQL database back end.
- Connection settings are performed with <a href="t.connect.html">t.connect</a>.
- As default a sqlite3 database will be created in the current mapset that
- stores all space time datasets and registered time series maps.
- <p>
- New space time datasets are created in the temporal database with
- <a href="t.create.html">t.create</a>. The name of the new dataset, the
- type (strds, str3ds, stvds), the title and the description must be
- provided for creation. Optional the temporal type (absolute, relative)
- and semantic informations can be provided.
- <p>
- The module <a href="t.remove.html">t.remove</a> will remove the space time datasets
- from the temporal database. Use <a href="t.support.html">t.support</a>
- to modify the metadata of space time datasets or to update the metadata
- that is derived from registered maps. This module also checks for removed
- and modified maps and updates the space time datasets accordingly.
- Rename a space time dataset with <a href="t.rename.html">t.rename</a>.
- <p>
- The module <a href="t.register.html">t.register</a> is designed to
- register raster, 3D raster and vector maps in the temporal database and
- optionally in a space time dataset. It supports different input options. Maps
- to register can be provided as a comma separated string at the command line, or
- in an input file. The module supports the definition of time stamps
- (time instances or intervals) for each map in the input file.
- With <a href="t.unregister.html">t.unregister</a> maps can be unregistered
- from space time datasets and the temporal database.
- <p>
- To print informations about space time datasets or registered maps, the
- module <a href="t.info.html">t.info</a> can be used.
- <a href="t.list.html">t.list</a> will list all space time datasets and
- registered maps in the temporal database.
- <p>
- To compute and check the temporal topology of a space time datasets the
- module <a href="t.topology.html">t.topology</a> was designed. The module
- <a href="t.sample.html">t.sample</a> samples input space time dataset(s)
- with a sample space time dataset and print the result to standard output.
- Several different sample methods are supported that can be combined.
- <p>
- List of general management modules:
- <ul>
- <li><a href="t.connect.html">t.connect</a></li>
- <li><a href="t.create.html">t.create</a></li>
- <li><a href="t.rename.html">t.rename</a></li>
- <li><a href="t.remove.html">t.remove</a></li>
- <li><a href="t.register.html">t.register</a></li>
- <li><a href="t.unregister.html">t.unregister</a></li>
- <li><a href="t.info.html">t.info</a></li>
- <li><a href="t.list.html">t.list</a></li>
- <li><a href="t.sample.html">t.sample</a></li>
- <li><a href="t.support.html">t.support</a></li>
- <li><a href="t.topology.html">t.topology</a></li>
- </ul>
- <h3>Modules to visualize space time datasets and temporal data</h3>
- <ul>
- <li><a href="g.gui.animation.html">g.gui.animation</a></li>
- <li><a href="g.gui.timeline.html">g.gui.timeline</a></li>
- <li><a href="g.gui.mapswipe.html">g.gui.mapswipe</a></li>
- <li><a href="g.gui.tplot.html">g.gui.tplot</a></li>
- </ul>
- <h3>Modules to process space time raster datasets</h3>
- The focus of the temporal GIS framework is the processing and analysis of
- raster time series. Hence the majority of the temporal modules are designed to process space time raster
- datasets. However, there are several modules to process space time 3D raster datasets
- and space time vector datasets.
- <h4>Querying and map calculation</h4>
- Registered maps of a space time raster datasets can be listed using
- <a href="t.rast.list.html">t.rast.list</a>. This module supports several
- methods how the maps should be listed using SQL queries do determine how
- they are selected and sorted. Subsets of space time raster datasets can
- be extracted with <a href="t.rast.extract.html">t.rast.extract</a> that
- allows additionally to perform mapcalc operations on the selected raster
- maps.
- <ul>
- <li><a href="t.rast.extract.html">t.rast.extract</a></li>
- <li><a href="t.rast.gapfill.html">t.rast.gapfill</a></li>
- <li><a href="t.rast.mapcalc.html">t.rast.mapcalc</a></li>
- <li><a href="t.rast.colors.html">t.rast.colors</a></li>
- <li><a href="t.rast.neighbors.html">t.rast.neighbors</a></li>
- </ul>
- <h4>Aggregation and accumulation analysis</h4>
- The temporal framework support the aggregation of space time raster
- datasets. It provides three modules to perform aggregation using different
- approaches. To aggregate a space time raster map using a temporal
- granularity like 4 months, 7 days and so on use
- <a href="t.rast.aggregate.html">t.rast.aggregate</a>. The module
- <a href="t.rast.aggregate.ds.html">t.rast.aggregate.ds</a> allows the
- aggregation of raster map series using the intervals of the maps (raster,
- 3D raster and vector) of a 2. space time dataset. A simple interface to
- <a href="r.series.html">r.series</a> is the module
- <a href="t.rast.series.html">t.rast.series</a> that processes the whole
- input space time raster dataset or a subset of it.
- <ul>
- <li><a href="t.rast.aggregate.html">t.rast.aggregate</a></li>
- <li><a href="t.rast.aggregate.ds.html">t.rast.aggregate.ds</a></li>
- <li><a href="t.rast.series.html">t.rast.series</a></li>
- <li><a href="t.rast.accumulate.html">t.rast.accumulate</a></li>
- <li><a href="t.rast.accdetect.html">t.rast.accdetect</a></li>
- </ul>
- <h4>Export/import conversion</h4>
- Space time raster datasets can be exported with <a href="t.rast.export.html">t.rast.export</a>
- as compressed tar archive. Such archives can be imported
- using <a href="t.rast.import.html">t.rast.import</a>,
- <p>
- The module <a href="t.rast.to.rast3.html">t.rast.to.rast3</a> converts
- space time raster datasets into space time voxel cubes. All 3D raster modules
- can be used to process such voxel cubes. This conversion allows the export of space time raster datasets
- as netcdf files that include time as one dimension.
- <ul>
- <li><a href="t.rast.export.html">t.rast.export</a></li>
- <li><a href="t.rast.import.html">t.rast.import</a></li>
- <li><a href="t.rast.out.vtk.html">t.rast.out.vtk</a></li>
- <li><a href="t.rast.to.rast3.html">t.rast.to.rast3</a></li>
- <li><a href="r3.out.netcdf.html">r3.out.netcdf</a></li>
- </ul>
- <h4>Statistics and gap filling</h4>
- <ul>
- <li><a href="t.rast.gapfill.html">t.rast.gapfill</a></li>
- <li><a href="t.rast.univar.html">t.rast.univar</a></li>
- </ul>
- <h3>Modules to manage, process and analyze STR3DS and STVDS</h3>
- Several space time vector dataset modules were developed, to allow the handling
- of vector time series data.
- <ul>
- <li><a href="t.vect.extract.html">t.vect.extract</a></li>
- <li><a href="t.vect.import.html">t.vect.import</a></li>
- <li><a href="t.vect.export.html">t.vect.export</a></li>
- <li><a href="t.vect.observe.strds.html">t.vect.observe.strds</a></li>
- <li><a href="t.vect.univar.html">t.vect.univar</a></li>
- <li><a href="t.vect.what.strds.html">t.vect.what.strds</a></li>
- <li><a href="t.vect.db.select.html">t.vect.db.select</a></li>
- </ul>
- The space time 3D raster dataset modules are doing exactly the same as their raster
- pendants but with 3D raster map layers:
- <ul>
- <li><a href="t.rast3d.list.html">t.rast3d.list</a></li>
- <li><a href="t.rast3d.extract.html">t.rast3d.extract</a></li>
- <li><a href="t.rast3d.mapcalc.html">t.rast3d.mapcalc</a></li>
- <li><a href="t.rast3d.univar.html">t.rast3d.univar</a></li>
- </ul>
- <h4>See also</h4>
- <ul>
- <li>Gebbert, S., Pebesma, E., 2014. TGRASS: A temporal GIS for field based
- environmental modeling. Environmental Modelling & Software 53, 1-12.
- (<a href="http://dx.doi.org/10.1016/j.envsoft.2013.11.001">DOI</a>)</li>
- <li>Vaclav Petras, Anna Petrasova, Helena Mitasova, Markus Neteler, <b>FOSS4G 2014 workshop</b>: <br>
- <a href="http://fatra.cnr.ncsu.edu/temporal-grass-workshop/">Spatio-temporal data handling and visualization in GRASS GIS</a></li>
- <li><a href="http://www.geostat-course.org/Topic_Gebbert">GeoStat TGRASS Course</a></li>
- </ul>
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