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root/radiance/ray/doc/man/man1/gensdaymtx.1
Revision: 1.1
Committed: Fri Aug 2 19:10:18 2024 UTC (10 months, 2 weeks ago) by greg
Branch: MAIN
Log Message:
feat(gensdaymtx,epw2wea,genssky): Taoning added new gensdaymtx and updated others

File Contents

# Content
1 .\" RCSid $Id: gensdaymtx.1,v 1.16 2022/08/13 17:24:56 greg Exp $
2 .TH GENSDAYMTX 1 01/19/13 RADIANCE
3 .SH NAME
4 gensdaymtx - generate an annual spectral sky matrix from a weather tape
5 .SH SYNOPSIS
6 .B gensdaymtx
7 [
8 .B "\-v"
9 ][
10 .B "\-h"
11 ][
12 .B "\-d|\-s"
13 ][
14 .B "\-u"
15 ]][
16 .B "\-r deg"
17 ][
18 .B "\-m N"
19 ][
20 .B "\-p Dir"
21 ][
22 .B "\-n N"
23 ][
24 .B "-o{f|d}"
25 ]
26 [
27 .B "tape.wea"
28 ]
29 .SH DESCRIPTION
30 .I Gensdaymtx
31 takes a weather tape as input and produces a matrix of spectral sky patch
32 values using the precomputed atmospheric scattering model.
33 The weather tape is assumed to be in a special form of the .wea file, which contains
34 a short header with the site parameters followed
35 by the month, day, standard time, direct normal and diffuse horizontal
36 irradiance values, total cloud cover, and broadband aerosol optical depth, one time step per line.
37 Such file can be generated by
38 .I epw2wea
39 with appending
40 .I \-a
41 flag.
42 Each time step line is used to compute a column in the output matrix,
43 where rows correspond to sky patch positions, starting with 0 for
44 the ground and continuing to 145 for the zenith using the default
45 .I "\-m 1"
46 parameter setting.
47 .PP
48 .I Gensdaymtx
49 uses the OPAC continental average aerosol profile for the Mie scattering calculation.
50 For every distinct AOD value in the weather tape, a new set of the atmospheric parameters
51 is computed and stored in the atmos_data directory in the current directory, which
52 can be changed using the -p flag. This precomputation can be sped up using the
53 .I \-n NThreads
54 option. There is no speedup after NTHREADS=16.
55 .PP
56 Increasing the
57 .I \-m
58 parameter yields a higher resolution
59 sky using the Reinhart patch subdivision.
60 For example, setting
61 .I "\-m 4"
62 yields a sky with 2305 patches plus one patch for the ground.
63 Each matrix entry is in fact 20 values, corresponding to
64 spectra from 380nm to 730nm at 20nm interval (watts/sr/meter^2).
65 Thus, an hourly weather tape for an entire year would
66 yield 8760x20 (175200) values per output line (row).
67 .PP
68 The
69 .I \-g
70 option may be used to specify a ground color.
71 The default value is
72 .I "\-g 0.2"
73 corresponding to a 20% gray.
74 .PP
75 If there is a sun in the description,
76 .I gensdaymtx
77 will include its contribution in the four nearest sky patches,
78 distributing energy according to centroid proximity.
79 The
80 .I \-d
81 option may be used to produce a sun-only matrix, with no sky contributions,
82 and the ground patch also set to zero.
83 Alternatively, the
84 .I \-s
85 option may be used to exclude any direct solar component from the output,
86 with the other sky and ground patches unaffected.
87 .PP
88 The
89 .I \-u
90 option ignores input times when the sun is below the horizon.
91 .PP
92 By default,
93 .I gensdaymtx
94 assumes the positive Y-axis points north such that the first sky patch
95 is in the Y-axis direction on the horizon, the second patch is just
96 west of that, and so on spiraling around to the final patch near the zenith.
97 The
98 .I \-r
99 (or
100 .I \-rz)
101 option rotates the sky the specified number of degrees counter-clockwise
102 about the zenith, i.e., west of north.
103 This is in keeping with the effect of passing the output of
104 .I gensky(1)
105 or
106 .I gendaylit(1)
107 through
108 .I xform(1)
109 using a similar transform.
110 .PP
111 The
112 .I \-of
113 or
114 .I \-od
115 option may be used to specify binary float or double output, respectively.
116 This is much faster to write and to read, and is therefore preferred on
117 systems that support it.
118 (MS Windows is not one of them.)\0
119 The
120 .I \-h
121 option prevents the output of the usual header information.
122 Finally, the
123 .I \-v
124 option will enable verbose reporting, which is mostly useful for
125 finding out how many time steps are actually in the weather tape.
126 .SH EXAMPLES
127 Produce an annual spectral sky matrix without solar direct:
128 .IP "" .2i
129 epw2wea Detroit.epw Detroit.wea -a;
130 gensdaymtx -m 1 -s Detroit.wea > Detroit.mtx
131 .PP
132 Produce an hourly, annual Reinhart sky matrix
133 with 2306 patches including solar contributions
134 and send float output to
135 .I dctimestep(1)
136 to compute a sensor value matrix:
137 .IP "" .2i
138 gensdaymtx -m 4 -of VancouverBC.wea | dctimestep -if -n 8760 DCoef.mtx > res.dat
139 .SH AUTHORS
140 Taoning Wang adapted from gendaymtx
141 .SH "SEE ALSO"
142 dctimestep(1), genBSDF(1), gendaylit(1), gendaymtx(1), gensky(1), genskyvec(1),
143 rcollate(1), rcomb(1), rcontrib(1), rfluxmtx(1), xform(1)