| 1 | greg | 1.4 | .\" RCSid $Id: gendaymtx.1,v 1.3 2013/02/05 19:31:40 greg Exp $ | 
| 2 | greg | 1.1 | .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 "\-d|\-s" | 
| 11 |  |  | ][ | 
| 12 | greg | 1.2 | .B "\-r deg" | 
| 13 |  |  | ][ | 
| 14 | greg | 1.1 | .B "\-m N" | 
| 15 |  |  | ][ | 
| 16 |  |  | .B "\-g r g b" | 
| 17 |  |  | ][ | 
| 18 |  |  | .B "\-c r g b" | 
| 19 |  |  | ][ | 
| 20 |  |  | .B "-o{f|d}" | 
| 21 | greg | 1.4 | ][ | 
| 22 |  |  | .B "-O{0|1}" | 
| 23 | greg | 1.1 | ] | 
| 24 |  |  | [ | 
| 25 |  |  | .B "tape.wea" | 
| 26 |  |  | ] | 
| 27 |  |  | .SH DESCRIPTION | 
| 28 |  |  | .I Gendaymtx | 
| 29 |  |  | takes a weather tape as input and produces a matrix of sky patch | 
| 30 |  |  | values using the Perez all-weather model. | 
| 31 |  |  | The weather tape is assumed to be in the simple ASCII format understood | 
| 32 |  |  | by DAYSIM, which contains a short header with the site parameters followed | 
| 33 |  |  | by the month, day, standard time, direct normal and diffuse horizontal | 
| 34 |  |  | irradiance values, one time step per line. | 
| 35 |  |  | Each time step line is used to compute a column in the output matrix, | 
| 36 |  |  | where rows correspond to sky patch positions, starting with 0 for | 
| 37 |  |  | the ground and continuing to 145 for the zenith using the default | 
| 38 |  |  | .I "\-m 1" | 
| 39 |  |  | parameter setting. | 
| 40 |  |  | .PP | 
| 41 |  |  | Increasing the | 
| 42 |  |  | .I \-m | 
| 43 |  |  | parameter, typically by factors of two, yields a higher resolution | 
| 44 |  |  | sky using the Reinhart patch subdivision. | 
| 45 |  |  | For example, setting | 
| 46 |  |  | .I "\-m 4" | 
| 47 |  |  | yields a sky with 2305 patches plus one patch for the ground. | 
| 48 |  |  | Each matrix entry is in fact three values, corresponding to | 
| 49 |  |  | red green and blue radiance channels (watts/sr/meter^2). | 
| 50 |  |  | Thus, an hourly weather tape for an entire year would | 
| 51 |  |  | yield 8760x3 (26280) values per output line (row). | 
| 52 |  |  | .PP | 
| 53 |  |  | The | 
| 54 |  |  | .I \-c | 
| 55 |  |  | option may be used to specify a color for the sky. | 
| 56 |  |  | The gray value should equal 1 for proper energy balance | 
| 57 |  |  | The default sky color is | 
| 58 |  |  | .I "\-c 0.960 1.004 1.118". | 
| 59 |  |  | Similarly, the | 
| 60 |  |  | .I \-g | 
| 61 |  |  | option may be used to specify a ground color. | 
| 62 |  |  | The default value is | 
| 63 |  |  | .I "\-g 0.2 0.2 0.2" | 
| 64 |  |  | corresponding to a 20% gray. | 
| 65 |  |  | .PP | 
| 66 |  |  | The | 
| 67 |  |  | .I \-d | 
| 68 |  |  | option may be used to produce a sun-only matrix, with no sky contributions. | 
| 69 |  |  | Alternatively, the | 
| 70 |  |  | .I \-s | 
| 71 |  |  | option may be used to exclude any direct solar component from the output. | 
| 72 |  |  | .PP | 
| 73 | greg | 1.3 | By default, | 
| 74 |  |  | .I gendaymtx | 
| 75 |  |  | assumes the positive Y-axis points north such that the first sky patch | 
| 76 |  |  | is in the Y-axis direction on the horizon, the second patch is just | 
| 77 |  |  | west of that, and so on spiraling around to the final patch near the zenith. | 
| 78 | greg | 1.1 | The | 
| 79 | greg | 1.2 | .I \-r | 
| 80 |  |  | (or | 
| 81 |  |  | .I \-rz) | 
| 82 |  |  | option rotates the sky the specified number of degrees counter-clockwise | 
| 83 | greg | 1.3 | about the zenith, i.e., west of north. | 
| 84 | greg | 1.2 | This is in keeping with the effect of passing the output of | 
| 85 |  |  | .I gensky(1) | 
| 86 |  |  | or | 
| 87 |  |  | .I gendaylit(1) | 
| 88 |  |  | through | 
| 89 |  |  | .I xform(1) | 
| 90 |  |  | using a similar transform. | 
| 91 |  |  | .PP | 
| 92 |  |  | The | 
| 93 | greg | 1.1 | .I \-of | 
| 94 |  |  | or | 
| 95 |  |  | .I \-od | 
| 96 |  |  | option may be used to specify binary float or double output, respectively. | 
| 97 |  |  | This is much faster to write and to read, and is therefore preferred on | 
| 98 |  |  | systems that support it. | 
| 99 |  |  | (MS Windows is not one of them.)\0 | 
| 100 | greg | 1.4 | The | 
| 101 |  |  | .I \-O1 | 
| 102 |  |  | option specifies that output should be total solar radiance rather | 
| 103 |  |  | than visible radiance. | 
| 104 | greg | 1.1 | Finally, the | 
| 105 |  |  | .I \-v | 
| 106 |  |  | option will enable verbose reporting, which is mostly useful for | 
| 107 |  |  | finding out how many time steps are actually in the weather tape. | 
| 108 |  |  | .SH EXAMPLES | 
| 109 |  |  | Produce an uncolored Tregenza sky matrix without solar direct: | 
| 110 |  |  | .IP "" .2i | 
| 111 |  |  | gendaymtx -m 1 -c 1 1 1 -s Detroit.wea > Detroit.mtx | 
| 112 |  |  | .PP | 
| 113 |  |  | Produce an hourly, annual Reinhart sky matrix | 
| 114 |  |  | with 2306 patches including solar contributions | 
| 115 |  |  | and send float output to | 
| 116 |  |  | .I dctimestep(1) | 
| 117 |  |  | to compute a sensor value matrix: | 
| 118 |  |  | .IP "" .2i | 
| 119 |  |  | gendaymtx -m 4 -of VancouverBC.wea | dctimestep -if -n 8760 DCoef.mtx > res.dat | 
| 120 |  |  | .SH AUTHORS | 
| 121 |  |  | Ian Ashdown wrote most of the code, | 
| 122 |  |  | based on Jean-Jacques Delaunay's original gendaylit(1) implementation. | 
| 123 |  |  | Greg Ward wrote the final parameter parsing and weather tape conversion. | 
| 124 |  |  | .SH "SEE ALSO" | 
| 125 | greg | 1.2 | dctimestep(1), genBSDF(1), gendaylit(1), gensky(1), genskyvec(1), rcontrib(1), | 
| 126 |  |  | xform(1) |