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Revision: 1.12
Committed: Mon Apr 13 17:12:19 2020 UTC (5 years, 2 months ago) by greg
Branch: MAIN
Changes since 1.11: +23 -3 lines
Log Message:
Updates to gendaymtx requested by Ladybug Tools

File Contents

# Content
1 .\" RCSid $Id: gendaymtx.1,v 1.11 2020/01/07 01:42:30 greg Exp $
2 .TH GENDAYMTX 1 01/19/13 RADIANCE
3 .SH NAME
4 gendaymtx - generate an annual Perez sky matrix from a weather tape
5 .SH SYNOPSIS
6 .B gendaymtx
7 [
8 .B "\-v"
9 ][
10 .B "\-h"
11 ][
12 .B "\-A"
13 ][
14 .B "\-d|\-s|\-n"
15 ][
16 .B "\-D sunfile"
17 ][
18 .B "\-M sunmods"
19 ][
20 .B "\-r deg"
21 ][
22 .B "\-m N"
23 ][
24 .B "\-g r g b"
25 ][
26 .B "\-c r g b"
27 ][
28 .B "-o{f|d}"
29 ][
30 .B "-O{0|1}"
31 ]
32 [
33 .B "tape.wea"
34 ]
35 .SH DESCRIPTION
36 .I Gendaymtx
37 takes a weather tape as input and produces a matrix of sky patch
38 values using the Perez all-weather model.
39 The weather tape is assumed to be in the simple ASCII format understood
40 by DAYSIM, which contains a short header with the site parameters followed
41 by the month, day, standard time, direct normal and diffuse horizontal
42 irradiance values, one time step per line.
43 Each time step line is used to compute a column in the output matrix,
44 where rows correspond to sky patch positions, starting with 0 for
45 the ground and continuing to 145 for the zenith using the default
46 .I "\-m 1"
47 parameter setting.
48 .PP
49 Increasing the
50 .I \-m
51 parameter yields a higher resolution
52 sky using the Reinhart patch subdivision.
53 For example, setting
54 .I "\-m 4"
55 yields a sky with 2305 patches plus one patch for the ground.
56 Each matrix entry is in fact three values, corresponding to
57 red green and blue radiance channels (watts/sr/meter^2).
58 Thus, an hourly weather tape for an entire year would
59 yield 8760x3 (26280) values per output line (row).
60 .PP
61 The
62 .I \-A
63 option tells
64 .I gendaymtx
65 to generate a single column corresponding to an average sky
66 computed over all the input time steps, rather than one
67 column per time step.
68 .PP
69 The
70 .I \-c
71 option may be used to specify a color for the sky.
72 The gray value should equal 1 for proper energy balance.
73 The default sky color is
74 .I "\-c 0.960 1.004 1.118".
75 Similarly, the
76 .I \-g
77 option may be used to specify a ground color.
78 The default value is
79 .I "\-g 0.2 0.2 0.2"
80 corresponding to a 20% gray.
81 .PP
82 The
83 .I \-d
84 option may be used to produce a sun-only matrix, with no sky contributions,
85 and the ground patch also set to zero.
86 Alternatively, the
87 .I \-s
88 option may be used to exclude any direct solar component from the output,
89 with the rest of the sky and ground patch unaffected.
90 If there is a sun in the description,
91 .I gendaymtx
92 will include its contribution in the four nearest sky patches,
93 distributing energy according to centroid proximity.
94 .PP
95 The
96 .I \-n
97 option may be used if no matrix output is desired.
98 This may be used to merely check the input, or in combination with the
99 .I \-D
100 option, below.
101 .PP
102 The
103 .I \-D
104 option may be used to specify an output file to contain a list of
105 solar positions and intensities corresponding to time steps in the
106 weather tape where the sun has any portion above the horizion.
107 Sun radiance values may be zero if the direct amount is zero on the input.
108 Sun modifiers and names will be indexed by the minute, numbered from
109 midnight, January 1st.
110 If a hyphen ('-') is given as the argument to
111 .I \-D,
112 then the sun descriptions will be directed to the standard output.
113 This implies the
114 .I \-n
115 option just described.
116 If the
117 .I \-M
118 option is given as well, it will be used to record the modifier
119 names used in the
120 .I \-D
121 output, for convenient input to
122 .I rcontrib(1)
123 and
124 .I rfluxmtx(1).
125 .PP
126 By default,
127 .I gendaymtx
128 assumes the positive Y-axis points north such that the first sky patch
129 is in the Y-axis direction on the horizon, the second patch is just
130 west of that, and so on spiraling around to the final patch near the zenith.
131 The
132 .I \-r
133 (or
134 .I \-rz)
135 option rotates the sky the specified number of degrees counter-clockwise
136 about the zenith, i.e., west of north.
137 This is in keeping with the effect of passing the output of
138 .I gensky(1)
139 or
140 .I gendaylit(1)
141 through
142 .I xform(1)
143 using a similar transform.
144 .PP
145 The
146 .I \-of
147 or
148 .I \-od
149 option may be used to specify binary float or double output, respectively.
150 This is much faster to write and to read, and is therefore preferred on
151 systems that support it.
152 (MS Windows is not one of them.)\0
153 The
154 .I \-O1
155 option specifies that output should be total solar radiance rather
156 than visible radiance.
157 The
158 .I \-h
159 option prevents the output of the usual header information.
160 Finally, the
161 .I \-v
162 option will enable verbose reporting, which is mostly useful for
163 finding out how many time steps are actually in the weather tape.
164 .SH EXAMPLES
165 Produce an uncolored Tregenza sky matrix without solar direct:
166 .IP "" .2i
167 gendaymtx -m 1 -c 1 1 1 -s Detroit.wea > Detroit.mtx
168 .PP
169 Produce an hourly, annual Reinhart sky matrix
170 with 2306 patches including solar contributions
171 and send float output to
172 .I dctimestep(1)
173 to compute a sensor value matrix:
174 .IP "" .2i
175 gendaymtx -m 4 -of VancouverBC.wea | dctimestep -if -n 8760 DCoef.mtx > res.dat
176 .SH AUTHORS
177 Ian Ashdown wrote most of the code,
178 based on Jean-Jacques Delaunay's original gendaylit(1) implementation.
179 Greg Ward wrote the final parameter parsing and weather tape conversion.
180 .SH "SEE ALSO"
181 dctimestep(1), genBSDF(1), gendaylit(1), gensky(1), genskyvec(1),
182 rcollate(1), rcontrib(1), rfluxmtx(1), xform(1)