## DESCRIPTION

t.rast.neighbors performs r.neighbors computations on the maps of a space time raster dataset (STRDS). This module supports a subset of options that are available in r.neighbors. The size of the neighborhood and the aggregation method can be chosen.

The user must provide an input and an output space time raster dataset and the basename of the resulting raster maps. The resulting STRDS will have the same temporal resolution as the input dataset. All maps will be processed using the current region settings.

The user can select a subset of the input space time raster dataset for processing using a SQL WHERE statement. The number of CPU's to be used for parallel processing can be specified with the nprocs option, to speedup the computation on multicore system.

## EXAMPLE

In this example we create 7 raster maps that will be registered in a single space time raster dataset named precipitation_daily using a daily temporal granularity. The names of the raster maps are stored in a text file that is used for raster map registration.

A neighborhood average smoothing with a window size of 5 cells will be performed on the space time raster dataset precipitation_daily resulting in the output space time raster dataset precipitation_daily_smooth. The base name of the new generated raster maps is prec_smooth. The temporal resolution of the resulting STRDS is identical to the input STRDS.

    MAPS="map_1 map_2 map_3 map_4 map_5 map_6 map_7"

    count=1
    for map in ${MAPS} ; do
        export GRASS_RND_SEED=${count}
        r.mapcalc --o expr="${map} = rand(0, 550)"
        echo ${map} >> map_list.txt
        count=$((count+1))
    done

    t.create --o type=strds temporaltype=absolute \
             output=precipitation_daily \
             title="Daily precipitation" \
             description="Test dataset with daily precipitation"

    t.register -i --o type=rast input=precipitation_daily \
               file=map_list.txt start="2012-08-20" increment="1 days"

    t.info type=strds input=precipitation_daily

     +-------------------- Space Time Raster Dataset -----------------------------+
     |                                                                            |
     +-------------------- Basic information -------------------------------------+
     | Id: ........................ precipitation_daily@PERMANENT
     | Name: ...................... precipitation_daily
     | Mapset: .................... PERMANENT
     | Creator: ................... soeren
     | Creation time: ............. 2013-03-20 18:47:25.867658
     | Temporal type: ............. absolute
     | Semantic type:.............. mean
     +-------------------- Absolute time -----------------------------------------+
     | Start time:................. 2012-08-20 00:00:00
     | End time:................... 2012-08-27 00:00:00
     | Granularity:................ 1 days
     | Temporal type of maps:...... interval
     +-------------------- Spatial extent ----------------------------------------+
     | North:...................... 80.0
     | South:...................... 0.0
     | East:.. .................... 120.0
     | West:....................... 0.0
     | Top:........................ 0.0
     | Bottom:..................... 0.0
     +-------------------- Metadata information ----------------------------------+
     | Number of registered maps:.. 7
     | Title:
     | Daily precipitation
     | Description:
     | Test dataset with daily precipitation
     | North-South resolution min:. 10.0
     | North-South resolution max:. 10.0
     | East-west resolution min:... 10.0
     | East-west resolution max:... 10.0
     | Minimum value min:.......... 0.0
     | Minimum value max:.......... 8.0
     | Maximum value min:.......... 533.0
     | Maximum value max:.......... 549.0
     | Raster register table:...... precipitation_daily_PERMANENT_raster_register
     +----------------------------------------------------------------------------+

    t.rast.list input=precipitation_daily columns=name,start_time,min,max

    map_1   2012-08-20 00:00:00     2.0     549.0
    map_2   2012-08-21 00:00:00     4.0     549.0
    map_3   2012-08-22 00:00:00     8.0     548.0
    map_4   2012-08-23 00:00:00     3.0     549.0
    map_5   2012-08-24 00:00:00     0.0     533.0
    map_6   2012-08-25 00:00:00     2.0     543.0
    map_7   2012-08-26 00:00:00     1.0     539.0

    t.rast.neighbors --o input=precipitation_daily \
        output=precipitation_daily_smooth base=prec_smooth \
        size=5 method=average nprocs=3

    t.info type=strds input=precipitation_daily_smooth

     +-------------------- Space Time Raster Dataset -----------------------------+
     |                                                                            |
     +-------------------- Basic information -------------------------------------+
     | Id: ........................ precipitation_daily_smooth@PERMANENT
     | Name: ...................... precipitation_daily_smooth
     | Mapset: .................... PERMANENT
     | Creator: ................... soeren
     | Creation time: ............. 2013-03-20 18:47:28.697990
     | Temporal type: ............. absolute
     | Semantic type:.............. mean
     +-------------------- Absolute time -----------------------------------------+
     | Start time:................. 2012-08-20 00:00:00
     | End time:................... 2012-08-27 00:00:00
     | Granularity:................ 1 days
     | Temporal type of maps:...... interval
     +-------------------- Spatial extent ----------------------------------------+
     | North:...................... 80.0
     | South:...................... 0.0
     | East:.. .................... 120.0
     | West:....................... 0.0
     | Top:........................ 0.0
     | Bottom:..................... 0.0
     +-------------------- Metadata information ----------------------------------+
     | Number of registered maps:.. 7
     | Title:
     | Daily precipitation
     | Description:
     | Test dataset with daily precipitation
     | North-South resolution min:. 10.0
     | North-South resolution max:. 10.0
     | East-west resolution min:... 10.0
     | East-west resolution max:... 10.0
     | Minimum value min:.......... 140.166667
     | Minimum value max:.......... 215.166667
     | Maximum value min:.......... 293.3
     | Maximum value max:.......... 373.388889
     | Raster register table:...... precipitation_daily_smooth_PERMANENT_raster_register
     +----------------------------------------------------------------------------+

    t.rast.list input=precipitation_daily_smooth columns=name,start_time,min,max

    prec_smooth_1   2012-08-20 00:00:00     172.388889      360.566667
    prec_smooth_2   2012-08-21 00:00:00     215.166667      322.833333
    prec_smooth_3   2012-08-22 00:00:00     140.166667      373.388889
    prec_smooth_4   2012-08-23 00:00:00     184.3           356.583333
    prec_smooth_5   2012-08-24 00:00:00     163.966667      293.3
    prec_smooth_6   2012-08-25 00:00:00     204.98          324.611111
    prec_smooth_7   2012-08-26 00:00:00     154.25          340.366667

## SEE ALSO

r.neighbors
t.rast.aggregate.ds
t.rast.extract
t.info
g.region
r.mask

## AUTHOR

Sören Gebbert

Last changed: $Date: 2012-08-29 14:55:21 +0200 (Mi, 29. Aug 2012) $