1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
<h2>DESCRIPTION</h2>
The purpose of <em>t.sample</em> 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 <em>sample</em> 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.
<p>
This module is useful to analyze temporal relationships between space
time datasets using temporal topology. The flag <em>-s</em> enables a
spatio-temporal topology, so that only spatio-temporal related map
layers of space time datasets are considered in the analysis.
<h2>NOTES</h2>
The temporal relation <em>start</em> means that the start time of an
input map layer is temporally located in an interval of a sample map
layer.
<p>
The textual output at the command line shows the names of the maps,
start and end time as well as the <em>interval length</em> in days and
the temporal <em>distance from begin</em> in days.
<p>
The default <em>separator</em> is the pipe symbol.
<p>
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 <em>None</em> is printed.
<h2>EXAMPLE</h2>
In the examples below we create a space time raster dataset <em>A</em>
and a space time vector dataset <em>P</em> 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.
<p>
We use <em>t.sample</em> to inspect the topological relations between the
time stamped map layers in <em>A</em> and <em>P</em>.
<p>
<div class="code"><pre>
# 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="a1 = rand(0, 550)" -s
r.mapcalc expression="a2 = rand(0, 450)" -s
r.mapcalc expression="a3 = rand(0, 320)" -s
r.mapcalc expression="a4 = rand(0, 510)" -s
r.mapcalc expression="a5 = rand(0, 300)" -s
r.mapcalc expression="a6 = rand(0, 650)" -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=`g.tempfile pid=1 -d`
n2=`g.tempfile pid=2 -d`
cat > "${n1}" << EOF
a1
a2
a3
a4
a5
a6
EOF
cat > "${n2}" << 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 \
title="A test with raster input files" descr="A test with raster input files"
t.create type=stvds temporaltype=absolute output=P \
title="A test with vector input files" descr="A test with vector input files"
t.register type=raster -i input=A file="${n1}" start="2001-01-01" increment="1 months"
# Raster map layer in A
t.rast.list A
name|mapset|start_time|end_time
a1|PERMANENT|2001-01-01 00:00:00|2001-02-01 00:00:00
a2|PERMANENT|2001-02-01 00:00:00|2001-03-01 00:00:00
a3|PERMANENT|2001-03-01 00:00:00|2001-04-01 00:00:00
a4|PERMANENT|2001-04-01 00:00:00|2001-05-01 00:00:00
a5|PERMANENT|2001-05-01 00:00:00|2001-06-01 00:00:00
a6|PERMANENT|2001-06-01 00:00:00|2001-07-01 00:00:00
t.register type=vector input=P file="${n2}"
# 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
</pre></div>
<h2>SEE ALSO</h2>
<em>
<a href="t.create.html">t.create</a>,
<a href="t.info.html">t.info</a>
</em>
<h2>AUTHOR</h2>
Sören Gebbert, Thünen Institute of Climate-Smart Agriculture
|
