Note: A new GRASS GIS stable version has been released: GRASS GIS 7.8, available here.
Updated manual page: here
NAME
t.rast.gapfill - Replaces gaps in a space time raster dataset with interpolated raster maps.KEYWORDS
temporal, interpolation, raster, time, no-data fillingSYNOPSIS
t.rast.gapfill
t.rast.gapfill --helpt.rast.gapfill [-t] input=name [where=sql_query] basename=string [suffix=string] [nprocs=integer] [--help] [--verbose] [--quiet] [--ui]
Flags:
- -t
- Assign the space time raster dataset start and end time to the output map
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- input=name [required]
- Name of the input space time raster dataset
- 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'
- basename=string [required]
- Basename of the new generated output maps
- A numerical suffix separated by an underscore will be attached to create a unique identifier
- suffix=string
- Suffix to add at basename: set 'gran' for granularity, 'time' for the full time format, 'num' for numerical suffix with a specific number of digits (default %05)
- Default: gran
- nprocs=integer
- Number of interpolation processes to run in parallel
- Default: 1
Table of contents
DESCRIPTION
t.rast.gapfill fills temporal gaps in space time raster datasets using linear interpolation. Temporal all gaps will be detected in the input space time raster dataset automatically. The predecessor and successor maps of the gaps will be identified and used to linear interpolate the raster map between them.NOTES
This module uses r.series.interp to perform the interpolation for each gap independently. Hence several interpolation processes can be run in parallel.Each gap is re-sampled by the space time raster dataset granularity. Therefore several time stamped raster map layers will be interpolated if the gap is larger than the STRDS granularity.
Examples
In this example we will create 3 raster maps and register them in the temporal database an then in the newly created space time raster dataset. There are gaps of one and two day size between the raster maps. The values of the maps are chosen so that the interpolated values can be estimated. We expect one map with a value of 2 for the first gap and two maps (values 3.666 and 4.333) for the second gap after interpolation.
r.mapcalc expression="map1 = 1"
r.mapcalc expression="map2 = 3"
r.mapcalc expression="map3 = 5"
t.register type=raster maps=map1 start=2012-08-20 end=2012-08-21
t.register type=raster maps=map2 start=2012-08-22 end=2012-08-23
t.register type=raster maps=map3 start=2012-08-25 end=2012-08-26
t.create type=strds temporaltype=absolute \
output=precipitation_daily \
title="Daily precipitation" \
description="Test dataset with daily precipitation"
t.register type=raster input=precipitation_daily maps=map1,map2,map3
# the output shows three missing maps
t.rast.list input=precipitation_daily columns=name,start_time,min,max
name|start_time|min|max
map1|2012-08-20 00:00:00|1.0|1.0
map2|2012-08-22 00:00:00|3.0|3.0
map3|2012-08-25 00:00:00|5.0|5.0
t.rast.list input=precipitation_daily method=deltagaps
id|name|mapset|start_time|end_time|interval_length|distance_from_begin
map1@PERMANENT|map1|PERMANENT|2012-08-20 00:00:00|2012-08-21 00:00:00|1.0|0.0
None|None|None|2012-08-21 00:00:00|2012-08-22 00:00:00|1.0|1.0
map2@PERMANENT|map2|PERMANENT|2012-08-22 00:00:00|2012-08-23 00:00:00|1.0|2.0
None|None|None|2012-08-23 00:00:00|2012-08-25 00:00:00|2.0|3.0
map3@PERMANENT|map3|PERMANENT|2012-08-25 00:00:00|2012-08-26 00:00:00|1.0|5.0
t.rast.gapfill input=precipitation_daily basename=gap
t.rast.list input=precipitation_daily columns=name,start_time,min,max
name|start_time|min|max
map1|2012-08-20 00:00:00|1.0|1.0
gap_6_1|2012-08-21 00:00:00|2.0|2.0
map2|2012-08-22 00:00:00|3.0|3.0
gap_7_1|2012-08-23 00:00:00|3.666667|3.666667
gap_7_2|2012-08-24 00:00:00|4.333333|4.333333
map3|2012-08-25 00:00:00|5.0|5.0
SEE ALSO
r.series.interp, t.create, t.infoAUTHOR
Sören Gebbert, Thünen Institute of Climate-Smart AgricultureLast changed: $Date$
SOURCE CODE
Available at: t.rast.gapfill source code (history)
Note: A new GRASS GIS stable version has been released: GRASS GIS 7.8, available here.
Updated manual page: here
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