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root/radiance/ray/doc/man/man1/gendaymtx.1
Revision: 1.7
Committed: Tue Jun 17 18:03:48 2014 UTC (10 years, 10 months ago) by greg
Branch: MAIN
CVS Tags: rad4R2P2, rad5R0, rad5R1, rad4R2, rad4R2P1
Changes since 1.6: +2 -2 lines
Log Message:
Hopeful fix to performance issue for gendaymtx under Windows

File Contents

# Content
1 .\" RCSid $Id: gendaymtx.1,v 1.6 2014/05/30 00:00:54 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 "\-d|\-s"
13 ][
14 .B "\-r deg"
15 ][
16 .B "\-m N"
17 ][
18 .B "\-g r g b"
19 ][
20 .B "\-c r g b"
21 ][
22 .B "-o{f|d}"
23 ][
24 .B "-O{0|1}"
25 ]
26 [
27 .B "tape.wea"
28 ]
29 .SH DESCRIPTION
30 .I Gendaymtx
31 takes a weather tape as input and produces a matrix of sky patch
32 values using the Perez all-weather model.
33 The weather tape is assumed to be in the simple ASCII format understood
34 by DAYSIM, which contains a short header with the site parameters followed
35 by the month, day, standard time, direct normal and diffuse horizontal
36 irradiance values, one time step per line.
37 Each time step line is used to compute a column in the output matrix,
38 where rows correspond to sky patch positions, starting with 0 for
39 the ground and continuing to 145 for the zenith using the default
40 .I "\-m 1"
41 parameter setting.
42 .PP
43 Increasing the
44 .I \-m
45 parameter, typically by factors of two, yields a higher resolution
46 sky using the Reinhart patch subdivision.
47 For example, setting
48 .I "\-m 4"
49 yields a sky with 2305 patches plus one patch for the ground.
50 Each matrix entry is in fact three values, corresponding to
51 red green and blue radiance channels (watts/sr/meter^2).
52 Thus, an hourly weather tape for an entire year would
53 yield 8760x3 (26280) values per output line (row).
54 .PP
55 The
56 .I \-c
57 option may be used to specify a color for the sky.
58 The gray value should equal 1 for proper energy balance.
59 The default sky color is
60 .I "\-c 0.960 1.004 1.118".
61 Similarly, the
62 .I \-g
63 option may be used to specify a ground color.
64 The default value is
65 .I "\-g 0.2 0.2 0.2"
66 corresponding to a 20% gray.
67 .PP
68 The
69 .I \-d
70 option may be used to produce a sun-only matrix, with no sky contributions.
71 Alternatively, the
72 .I \-s
73 option may be used to exclude any direct solar component from the output.
74 .PP
75 By default,
76 .I gendaymtx
77 assumes the positive Y-axis points north such that the first sky patch
78 is in the Y-axis direction on the horizon, the second patch is just
79 west of that, and so on spiraling around to the final patch near the zenith.
80 The
81 .I \-r
82 (or
83 .I \-rz)
84 option rotates the sky the specified number of degrees counter-clockwise
85 about the zenith, i.e., west of north.
86 This is in keeping with the effect of passing the output of
87 .I gensky(1)
88 or
89 .I gendaylit(1)
90 through
91 .I xform(1)
92 using a similar transform.
93 .PP
94 The
95 .I \-of
96 or
97 .I \-od
98 option may be used to specify binary float or double output, respectively.
99 This is much faster to write and to read, and is therefore preferred on
100 systems that support it.
101 (MS Windows is not one of them.)\0
102 The
103 .I \-O1
104 option specifies that output should be total solar radiance rather
105 than visible radiance.
106 The
107 .I \-h
108 option prevents the output of the usual header information.
109 Finally, the
110 .I \-v
111 option will enable verbose reporting, which is mostly useful for
112 finding out how many time steps are actually in the weather tape.
113 .SH EXAMPLES
114 Produce an uncolored Tregenza sky matrix without solar direct:
115 .IP "" .2i
116 gendaymtx -m 1 -c 1 1 1 -s Detroit.wea > Detroit.mtx
117 .PP
118 Produce an hourly, annual Reinhart sky matrix
119 with 2306 patches including solar contributions
120 and send float output to
121 .I dctimestep(1)
122 to compute a sensor value matrix:
123 .IP "" .2i
124 gendaymtx -m 4 -of VancouverBC.wea | dctimestep -if -n 8760 DCoef.mtx > res.dat
125 .SH AUTHORS
126 Ian Ashdown wrote most of the code,
127 based on Jean-Jacques Delaunay's original gendaylit(1) implementation.
128 Greg Ward wrote the final parameter parsing and weather tape conversion.
129 .SH "SEE ALSO"
130 dctimestep(1), genBSDF(1), gendaylit(1), gensky(1), genskyvec(1),
131 rcollate(1), rcontrib(1), xform(1)