.TH t.sample 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBt.sample\fR\fR  \- Samples the input space time dataset(s) with a sample space time dataset and print the result to stdout.
.SH KEYWORDS
temporal, sampling, time
.SH SYNOPSIS
\fBt.sample\fR
.br
\fBt.sample \-\-help\fR
.br
\fBt.sample\fR [\-\fBcs\fR] \fBinputs\fR=\fIname\fR[,\fIname\fR,...] \fBsample\fR=\fIname\fR  [\fBintype\fR=\fIname\fR]   [\fBsamtype\fR=\fIname\fR]   [\fBmethod\fR=\fIname\fR[,\fIname\fR,...]]   [\fBseparator\fR=\fIcharacter\fR]   [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-c\fR" 4m
.br
Print the column names as first row
.IP "\fB\-s\fR" 4m
.br
Check for spatial topological overlap
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBinputs\fR=\fIname[,\fIname\fR,...]\fR \fB[required]\fR" 4m
.br
Name of the input space time datasets
.IP "\fBsample\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of the sample space time dataset
.IP "\fBintype\fR=\fIname\fR" 4m
.br
Type of the input space time dataset
.br
Options: \fIstrds, stvds, str3ds\fR
.br
Default: \fIstrds\fR
.IP "\fBsamtype\fR=\fIname\fR" 4m
.br
Type of the sample space time dataset
.br
Options: \fIstrds, stvds, str3ds\fR
.br
Default: \fIstrds\fR
.IP "\fBmethod\fR=\fIname[,\fIname\fR,...]\fR" 4m
.br
The method to be used for sampling the input dataset
.br
Options: \fIstart, during, overlap, contain, equal, follows, precedes\fR
.br
Default: \fIduring,overlap,contain,equal\fR
.IP "\fBseparator\fR=\fIcharacter\fR" 4m
.br
Do not use \(dq,\(dq as this char is reserved to list several map ids in a sample granule
.br
Field separator between output columns, default is tabular \(dq | \(dq
.br
Default: \fIpipe\fR
.SH DESCRIPTION
The purpose of this module is to compute and to show spatio\-temporal
relations between space time datasets of different type. Several input
space time datasets are sampled by a \fIsample\fR space time dataset
using temporal topological relations. The types of the input space time
datasets and the type of the sample space time dataset can be
different.
.PP
This module is useful to analyze temporal relationships between space
time datasets using temporal topology. The flag \fI\-s\fR enables a
spatio\-temporal topology, so that only spatio\-temporal related map
layers of space time datasets are considered in the analysis.
.SH NOTES
The temporal relation \fIstart\fR means that the start time of an
input map layer is temporally located in an interval of a sample map
layer.
.PP
The textual output at the command line shows the names of the maps,
start and end time as well as the \fIinterval length\fR in days and
the temporal \fIdistance from begin\fR in days.
.PP
The default \fIseparator\fR is the pipe symbol.
.PP
Temporal gaps, if present, in the input and sampling space time
datasets will be used in the sampling process. Gaps have no map name,
instead \fINone\fR is printed.
.SH EXAMPLE
In the examples below we create a space time raster dataset \fIA\fR
and a space time vector dataset \fIP\fR that have different temporal
layouts and number of map layers. The space time vector dataset
contains a gap, that will be used in the sampling process.
.PP
We use \fIt.sample\fR to inspect the topological relations between the
time stamped map layers in \fIA\fR and \fIP\fR.
.PP
.br
.nf
\fC
# Set an appropriate region
g.region s=0 n=80 w=0 e=120 b=0 t=50 res=10 res3=10 \-p3
# Generate the raster map layer
r.mapcalc expression=\(dqa1 = rand(0, 550)\(dq \-s
r.mapcalc expression=\(dqa2 = rand(0, 450)\(dq \-s
r.mapcalc expression=\(dqa3 = rand(0, 320)\(dq \-s
r.mapcalc expression=\(dqa4 = rand(0, 510)\(dq \-s
r.mapcalc expression=\(dqa5 = rand(0, 300)\(dq \-s
r.mapcalc expression=\(dqa6 = rand(0, 650)\(dq \-s
# Generate the vector map layer
v.random \-z output=pnts1 n=20 zmin=0 zmax=100 column=height
v.random \-z output=pnts2 n=20 zmin=0 zmax=100 column=height
n1=\(gag.tempfile pid=1 \-d\(ga
n2=\(gag.tempfile pid=2 \-d\(ga
cat > \(dq${n1}\(dq << EOF
a1
a2
a3
a4
a5
a6
EOF
cat > \(dq${n2}\(dq << EOF
pnts1|2001\-01\-01|2001\-03\-01
pnts2|2001\-05\-01|2001\-07\-01
EOF
# Register the maps in new space time datasets
t.create type=strds temporaltype=absolute output=A \(rs
    title=\(dqA test with raster input files\(dq descr=\(dqA test with raster input files\(dq
t.create type=stvds temporaltype=absolute output=P \(rs
    title=\(dqA test with vector input files\(dq descr=\(dqA test with vector input files\(dq
t.register type=raster \-i input=A file=\(dq${n1}\(dq start=\(dq2001\-01\-01\(dq increment=\(dq1 months\(dq
# Raster map layer in A
t.rast.list A
name|mapset|start_time|end_time
a1|PERMANENT|2001\-01\-01 00:00:00|2001\-02\-01 00:00:00
a2|PERMANENT|2001\-02\-01 00:00:00|2001\-03\-01 00:00:00
a3|PERMANENT|2001\-03\-01 00:00:00|2001\-04\-01 00:00:00
a4|PERMANENT|2001\-04\-01 00:00:00|2001\-05\-01 00:00:00
a5|PERMANENT|2001\-05\-01 00:00:00|2001\-06\-01 00:00:00
a6|PERMANENT|2001\-06\-01 00:00:00|2001\-07\-01 00:00:00
t.register type=vector input=P file=\(dq${n2}\(dq
# Vector map layer in P
t.vect.list P
name|layer|mapset|start_time|end_time
pnts1|None|PERMANENT|2001\-01\-01 00:00:00|2001\-03\-01 00:00:00
pnts2|None|PERMANENT|2001\-05\-01 00:00:00|2001\-07\-01 00:00:00
# Start time of maps in A located in maps in P
t.sample method=start input=A samtype=stvds sample=P \-c
P@PERMANENT|A@PERMANENT|start_time|end_time|interval_length|distance_from_begin
pnts1@PERMANENT|a1@PERMANENT,a2@PERMANENT|2001\-01\-01 00:00:00|2001\-03\-01 00:00:00|59.0|0.0
None|a3@PERMANENT,a4@PERMANENT|2001\-03\-01 00:00:00|2001\-05\-01 00:00:00|61.0|59.0
pnts2@PERMANENT|a5@PERMANENT,a6@PERMANENT|2001\-05\-01 00:00:00|2001\-07\-01 00:00:00|61.0|120.0
# P contains A
t.sample method=contain input=A samtype=stvds sample=P \-c
P@PERMANENT|A@PERMANENT|start_time|end_time|interval_length|distance_from_begin
pnts1@PERMANENT|a1@PERMANENT,a2@PERMANENT|2001\-01\-01 00:00:00|2001\-03\-01 00:00:00|59.0|0.0
None|a3@PERMANENT,a4@PERMANENT|2001\-03\-01 00:00:00|2001\-05\-01 00:00:00|61.0|59.0
pnts2@PERMANENT|a5@PERMANENT,a6@PERMANENT|2001\-05\-01 00:00:00|2001\-07\-01 00:00:00|61.0|120.0
# A during P
t.sample method=during intype=stvds input=P samtype=strds sample=A \-c
A@PERMANENT|P@PERMANENT|start_time|end_time|interval_length|distance_from_begin
a1@PERMANENT|pnts1@PERMANENT|2001\-01\-01 00:00:00|2001\-02\-01 00:00:00|31.0|0.0
a2@PERMANENT|pnts1@PERMANENT|2001\-02\-01 00:00:00|2001\-03\-01 00:00:00|28.0|31.0
a3@PERMANENT|None|2001\-03\-01 00:00:00|2001\-04\-01 00:00:00|31.0|59.0
a4@PERMANENT|None|2001\-04\-01 00:00:00|2001\-05\-01 00:00:00|30.0|90.0
a5@PERMANENT|pnts2@PERMANENT|2001\-05\-01 00:00:00|2001\-06\-01 00:00:00|31.0|120.0
a6@PERMANENT|pnts2@PERMANENT|2001\-06\-01 00:00:00|2001\-07\-01 00:00:00|30.0|151.0
# No Overlapping
t.sample method=overlap input=A samtype=stvds sample=P \-cs
P@PERMANENT|A@PERMANENT|start_time|end_time|interval_length|distance_from_begin
pnts1@PERMANENT|None|2001\-01\-01 00:00:00|2001\-03\-01 00:00:00|59.0|0.0
None|None|2001\-03\-01 00:00:00|2001\-05\-01 00:00:00|61.0|59.0
pnts2@PERMANENT|None|2001\-05\-01 00:00:00|2001\-07\-01 00:00:00|61.0|120.0
t.sample method=precedes input=A samtype=stvds sample=P \-c
P@PERMANENT|A@PERMANENT|start_time|end_time|interval_length|distance_from_begin
pnts1@PERMANENT|a3@PERMANENT|2001\-01\-01 00:00:00|2001\-03\-01 00:00:00|59.0|0.0
None|a5@PERMANENT|2001\-03\-01 00:00:00|2001\-05\-01 00:00:00|61.0|59.0
pnts2@PERMANENT|None|2001\-05\-01 00:00:00|2001\-07\-01 00:00:00|61.0|120.0
t.sample method=follows  input=A samtype=stvds sample=P \-c
P@PERMANENT|A@PERMANENT|start_time|end_time|interval_length|distance_from_begin
pnts1@PERMANENT|None|2001\-01\-01 00:00:00|2001\-03\-01 00:00:00|59.0|0.0
None|a2@PERMANENT|2001\-03\-01 00:00:00|2001\-05\-01 00:00:00|61.0|59.0
pnts2@PERMANENT|a4@PERMANENT|2001\-05\-01 00:00:00|2001\-07\-01 00:00:00|61.0|120.0
t.sample method=precedes,follows input=A samtype=stvds sample=P \-c
P@PERMANENT|A@PERMANENT|start_time|end_time|interval_length|distance_from_begin
pnts1@PERMANENT|a3@PERMANENT|2001\-01\-01 00:00:00|2001\-03\-01 00:00:00|59.0|0.0
None|a5@PERMANENT,a2@PERMANENT|2001\-03\-01 00:00:00|2001\-05\-01 00:00:00|61.0|59.0
pnts2@PERMANENT|a4@PERMANENT|2001\-05\-01 00:00:00|2001\-07\-01 00:00:00|61.0|120.0
\fR
.fi
.SH SEE ALSO
\fI
t.create,
t.info
\fR
.SH AUTHOR
Sören Gebbert, Thünen Institute of Climate\-Smart Agriculture
.SH SOURCE CODE
.PP
Available at: t.sample source code (history)
.PP
Main index |
Temporal index |
Topics index |
Keywords index |
Graphical index |
Full index
.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual