## NAME

t.register - Assigns timestamps and registers raster, vector and raster3d maps in a space time dataset.

## KEYWORDS

temporal, map management, register, time

## SYNOPSIS

t.register
t.register --help
t.register [-i] [input=name] [maps=name[,name,...]] [type=name] [file=name] [start=string] [end=string] [unit=string] [increment=string] [separator=character] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

### Flags:

-i
  Create an interval (start and end time) in case an increment and the start time are provided
--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
  Name of the input space time dataset
maps=name[,name,...]
  Name of the input maps
type=name
  Type of the input map
  Options: raster, vector, raster_3d
  Default: raster
file=name
  Input file with map names, one per line
  Additionally the start time and the end time can be specified per line
start=string
  Valid start date and time of the first map
  Format for absolute time: "yyyy-mm-dd HH:MM:SS +HHMM", relative time is of type integer.
end=string
  Valid end date and time of all map
  Format for absolute time: "yyyy-mm-dd HH:MM:SS +HHMM", relative time is of type integer.
unit=string
  Time stamp unit
  Unit must be set in case of relative timestamps
  Options: years, months, days, hours, minutes, seconds
increment=string
  Time increment, works only in conjunction with start option
  Time increment between maps for creation of valid time intervals (format for absolute time: NNN seconds, minutes, hours, days, weeks, months, years; format for relative time is of type integer: 5)
separator=character
  Field separator character of the input file
  Special characters: pipe, comma, space, tab, newline
  Default: pipe

## DESCRIPTION

The module t.register has double functionality: it either only assigns timestamps to raster, 3D raster and vector maps in the temporal database (if input option is not provided, see below) or additionally, it also registers them within input space time datasets (stds). The existing timestamp modules r.timestamp, r3.timestamp and v.timestamp do not register the maps in the temporal database of GRASS GIS. However, timestamps that have been created with these modules can be read and used by t.register. This works only for maps that are not already registered in the temporal database.

If the input option is not used (i.e., no stds is provided), maps will be only registered in the temporal database with assigned timestamps. If, on the other hand, the input option is used and a stds is provided, maps will be first registered in the temporal database (if not registered before) and then, in the stds specified. If the user wants to register maps that are already registered in the temporal database in a different stds, there is no need to pass information regarding start and end time, t.register will read timestamps from the temporal database (i.e., in this case only passing map names will be enough).

The module t.register supports absolute and relative time. The absolute temporal type refers to a fixed date while the relative temporal type refers to data without fixed timestamps (e.g., sequential maps used to calculate multi-decadal averages).

Maps can be registered by command line argument (i.e., a list of comma separated map names) or using an input file. The start time, end time and a temporal increment can be provided through command line or in the input file. End time and increment are mutually exclusive. The user can register single maps or a list of maps at once. Maps can be registered in several space time datasets using the same timestamp. For the case of vector time series, the user can also register a single vector map connected to different layers representing time steps using the map:layer notation (See example below).

The increment option and the -i flag (to create time intervals) work only in conjunction with the start option. If an input file with timestamps (either start time or start time and end time) is used, then the increment option and the -i flag are not supported.

Start time and end time with absolute time must be provided using the format yyyy-mm-dd HH:MM:SS +HHMM. It is also supported to specify only the date yyyy-mm-dd. In case of relative time, the temporal unit (years, months, days, hours, minutes or seconds) must be provided. In this case, the relative start time, end time and increment are integers.

## NOTES

The timestamps of registered maps will be stored in the temporal database and in the metadata of the grass maps in the spatial database. This assures that timestamps can always be accessed with (r|r3|v).timestamp and the temporal modules. Timestamps should only be modified with t.register because the (r|r3|v).timestamp modules have no access to the temporal database.

## INPUT FILE FORMAT

There are several options to register maps by means of a file. The input file consists of a list of map names, optionally along with timestamps. Each map name (and timestaps if provided) should be stored in a new line in this file.

When only map names are provided, the increment option and the -i flag are supported. However, when along with map names any kind of timestamp is provided, as well, the increment option and the -i are no longer supported.

Specification of map names only (increment option and -i flag supported):

    terra_lst_day20020113
    terra_lst_day20020114
    terra_lst_day20020115
    terra_lst_day20020116
    terra_lst_day20020117

Specification of map names and absolute start time (date) of the time instances (no support for increment option nor -i flag):

    terra_lst_day20020113|2002-01-13
    terra_lst_day20020114|2002-01-14
    terra_lst_day20020115|2002-01-15
    terra_lst_day20020116|2002-01-16
    terra_lst_day20020117|2002-01-17

Specification of map names and absolute start time (datetime) of the time instances (no support for increment option nor -i flag):

    terra_lst_day20020113|2002-01-13 10:30
    terra_lst_day20020114|2002-01-14 10:30
    terra_lst_day20020115|2002-01-15 10:30
    terra_lst_day20020116|2002-01-16 10:30
    terra_lst_day20020117|2002-01-17 10:30

Specification of map names and absolute time interval with start and end time (no support for increment option nor -i flag):

    prec_1|2001-01-01|2001-04-01
    prec_2|2001-04-01|2001-07-01
    prec_3|2001-07-01|2001-10-01
    prec_4|2001-10-01|2002-01-01
    prec_5|2002-01-01|2002-04-01
    prec_6|2002-04-01|2002-07-01

## EXAMPLE

### North Carolina dataset

#### Using a text file

Register maps in an absolute space time dataset, creating a time interval

    # first:  prepare a text file with a list of input maps (see above)
    # second: register maps
    t.register -i type=raster input=precipitation_monthly \
        file=list_of_input_maps.txt start="2009-01-01" \
        increment="1 months"

#### Using g.list to generate the input

Register maps in an absolute space time dataset, creating a time interval

    t.register -i type=raster input=precipitation_monthly \
        maps=`g.list raster pattern="*precip*" sep=comma` start="2009-01-01" \
        increment="1 months"

#### Register a vector map with layers representing time steps

Assume a vector map of points that represent meteorological stations and it is connected to different layers depicting daily time steps. In this example, only the fifth layer of the vector map will be registered.

    # the layer is specified behind the colon
    t.register type=vector input=meteo_stations_nc_daily \
        maps=meteo_stations_nc:5 start="2009-01-05"

### Synthetic maps

In this example we create 6 raster maps that will be registered in a single space time raster dataset named precip_abs using a monthly temporal granularity. The -i flag generates time intervals of the provided increment. The generated timestamps will be inspected using r.timestamp and t.rast.list. We will register an additional map with a timestamp that was set with r.timestamp.

    r.mapcalc expression="prec_1 = 100"
    r.mapcalc expression="prec_2 = 200"
    r.mapcalc expression="prec_3 = 300"
    r.mapcalc expression="prec_4 = 400"
    r.mapcalc expression="prec_5 = 500"
    r.mapcalc expression="prec_6 = 600"

    t.create type=strds temporaltype=absolute \
        output=precip_abs title="Example" \
        descr="Example"

    t.register -i type=raster input=precip_abs \
        maps=prec_1,prec_2,prec_3,prec_4,prec_5,prec_6 \
        start="2001-01-01" increment="1 months"

    r.timestamp prec_1
    1 Jan 2001 00:00:00 / 1 Feb 2001 00:00:00

    r.timestamp prec_2
    1 Feb 2001 00:00:00 / 1 Mar 2001 00:00:00

    t.rast.list input=precip_abs

    name|mapset|start_time|end_time
    prec_1|PERMANENT|2001-01-01 00:00:00|2001-02-01 00:00:00
    prec_2|PERMANENT|2001-02-01 00:00:00|2001-03-01 00:00:00
    prec_3|PERMANENT|2001-03-01 00:00:00|2001-04-01 00:00:00
    prec_4|PERMANENT|2001-04-01 00:00:00|2001-05-01 00:00:00
    prec_5|PERMANENT|2001-05-01 00:00:00|2001-06-01 00:00:00
    prec_6|PERMANENT|2001-06-01 00:00:00|2001-07-01 00:00:00

    r.mapcalc expression="prec_7 = 700"
    r.timestamp map=prec_7 date="1 jul 2001 / 1 aug 2001"

    t.register type=raster input=precip_abs maps=prec_7

    t.rast.list input=precip_abs

    name|mapset|start_time|end_time
    prec_1|PERMANENT|2001-01-01 00:00:00|2001-02-01 00:00:00
    prec_2|PERMANENT|2001-02-01 00:00:00|2001-03-01 00:00:00
    prec_3|PERMANENT|2001-03-01 00:00:00|2001-04-01 00:00:00
    prec_4|PERMANENT|2001-04-01 00:00:00|2001-05-01 00:00:00
    prec_5|PERMANENT|2001-05-01 00:00:00|2001-06-01 00:00:00
    prec_6|PERMANENT|2001-06-01 00:00:00|2001-07-01 00:00:00
    prec_7|PERMANENT|2001-07-01 00:00:00|2001-08-01 00:00:00

### Importing and registering ECA&D climatic data

The European Climate Assessment & Dataset (ECA&D) project offers the E-OBS dataset which is a daily gridded observational dataset for precipitation, temperature and sea level pressure in Europe based on ECA&D information. Download and decompress mean temperature data from: here by accepting their Terms of use.

    # import E-OBS V12 into a lat-long location (alternatively, use r.external)
    r.in.gdal -oe input=tg_0.25deg_reg_1950-1964_v12.0.nc \
      output=temperature_mean offset=0
    r.in.gdal -oe input=tg_0.25deg_reg_1965-1979_v12.0.nc \
      output=temperature_mean offset=5479 --o
    r.in.gdal -oe input=tg_0.25deg_reg_1980-1994_v12.0.nc \
      output=temperature_mean offset=10957 --o
    r.in.gdal -oe input=tg_0.25deg_reg_1995-2015_v12.0.nc \
      output=temperature_mean offset=16436 --o

    # create STRDS
    t.create type=strds output=temperature_mean_1950_2015_daily \
      temporaltype=absolute semantictype=mean \
      title="European mean temperature 1950-2015" \
      description="The European daily mean temperature from ECAD"

    # create text file with all temperature_mean rasters, one per line,
    # a) using a shell script
    for i in `seq 1 23922` ; do
        echo temperature_mean.$i >> map_list.txt
    done

    # b) using a Python script
    file = open("map_list.txt", "w")
    for i in range(23922):
        file.write("temperature_mean.%i\n" % (i + 1))
    file.close()

    # register daily maps using the file created above
    t.register -i type=raster input=temperature_mean_1950_2015_daily \
                  file=map_list.txt start="1950-01-01" increment="1 days"

## SEE ALSO

t.create, t.info

Maps registration examples in Temporal data processing Wiki

## AUTHOR

Sören Gebbert, Thünen Institute of Climate-Smart Agriculture

Last changed: $Date$

## SOURCE CODE

Available at: t.register source code (history)

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