## DESCRIPTION

The module t.register is designed to register raster, 3D raster and vector maps in the temporal database and in specific space time datasets. This module must be used to assign time stamps to raster, 3D raster and vector maps. The existing timestamp modules r.timestamp, r3.timestamp and v.timestamp do not register the maps in the temporal database of GRASS. 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.

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

Maps can be registered by command line argument (a list of comma separated map names) or using an input file. The start time, the end time and a temporal increment can be provided by command line or in the input file. End time and increment are mutual 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.

The increment option and the -i flag (to create time intervals) work only in conjunction with the start option. If an input file with time stamps 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 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. The relative start time, end time and the 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

The input file consists of a list of map names, optionally along with time stamps. Each map name is to be stored in a row in this file.

There are several options to register maps, increment option and the -i flag are supported:

Specification of map names:

    terra_lst_day20020113
    terra_lst_day20020114
    terra_lst_day20020115
    terra_lst_day20020116
    terra_lst_day20020117

Specification of map names and the absolute start time (date) of the time instances, not support for increment option and the -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 the absolute time stamp (datetime), not support for increment option and the -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 the map name and the absolute time interval with start, not support for increment option and the -i flag: and end time:

    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 a 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 a 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"

### 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 interval time. 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

## 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: 2016-01-13 00:30:14 +0100 (Wed, 13 Jan 2016) $