--- ray/doc/man/man1/gendaymtx.1	2020/04/13 17:12:19	1.12
+++ ray/doc/man/man1/gendaymtx.1	2025/02/26 20:39:28	1.19
@@ -1,4 +1,4 @@
-.\" RCSid $Id: gendaymtx.1,v 1.12 2020/04/13 17:12:19 greg Exp $
+.\" RCSid $Id: gendaymtx.1,v 1.19 2025/02/26 20:39:28 greg Exp $
 .TH GENDAYMTX 1 01/19/13 RADIANCE
 .SH NAME
 gendaymtx - generate an annual Perez sky matrix from a weather tape
@@ -13,10 +13,12 @@ gendaymtx - generate an annual Perez sky matrix from a
 ][
 .B "\-d|\-s|\-n"
 ][
-.B "\-D sunfile"
+.B "\-u"
 ][
+.B "\-D sunfile"
+[
 .B "\-M sunmods"
-][
+]][
 .B "\-r deg"
 ][
 .B "\-m N"
@@ -27,19 +29,26 @@ gendaymtx - generate an annual Perez sky matrix from a
 ][
 .B "-o{f|d}"
 ][
-.B "-O{0|1}"
+.B "\-O{0|1}"
+][
+.B "\-i intvl"
 ]
 [
 .B "tape.wea"
+or
+.B "tape.epw"
 ]
 .SH DESCRIPTION
 .I Gendaymtx
 takes a weather tape as input and produces a matrix of sky patch
 values using the Perez all-weather model.
-The weather tape is assumed to be in the simple ASCII format understood
+The weather tape may be in the simple ASCII format understood
 by DAYSIM, which contains a short header with the site parameters followed
 by the month, day, standard time, direct normal and diffuse horizontal
 irradiance values, one time step per line.
+Alternatively, a standard EPW (Energy Plus Weather) input may be provided,
+in which case additional information such as the dew point temperature may
+be used in the calculation.
 Each time step line is used to compute a column in the output matrix,
 where rows correspond to sky patch positions, starting with 0 for
 the ground and continuing to 145 for the zenith using the default
@@ -79,6 +88,10 @@ The default value is
 .I "\-g 0.2 0.2 0.2"
 corresponding to a 20% gray.
 .PP
+If there is a sun in the description,
+.I gendaymtx
+will include its contribution in the four nearest sky patches,
+distributing energy according to centroid proximity.
 The
 .I \-d
 option may be used to produce a sun-only matrix, with no sky contributions,
@@ -86,15 +99,21 @@ and the ground patch also set to zero.
 Alternatively, the
 .I \-s
 option may be used to exclude any direct solar component from the output,
-with the rest of the sky and ground patch unaffected.
-If there is a sun in the description,
-.I gendaymtx
-will include its contribution in the four nearest sky patches,
-distributing energy according to centroid proximity.
+with the other sky and ground patches unaffected.
 .PP
 The
+.I \-u
+option ignores input times when the sun is below the horizon.
+This is a convenient way to average daylight hours only with the
+.I \-A
+option or to ensure that matrix entries correspond to solar positions
+produced with the
+.I \-D
+option, described below.
+.PP
+The
 .I \-n
-option may be used if no matrix output is desired.
+option may be used if no matrix output is desired at all.
 This may be used to merely check the input, or in combination with the
 .I \-D
 option, below.
@@ -103,7 +122,7 @@ The
 .I \-D
 option may be used to specify an output file to contain a list of
 solar positions and intensities corresponding to time steps in the
-weather tape where the sun has any portion above the horizion.
+weather tape where the sun has any portion above the horizon.
 Sun radiance values may be zero if the direct amount is zero on the input.
 Sun modifiers and names will be indexed by the minute, numbered from
 midnight, January 1st.
@@ -143,6 +162,15 @@ through
 using a similar transform.
 .PP
 The
+.I \-i
+option specifies the actual capture interval in minutes of the original
+weather data.
+Please see the man page for
+.I gendaylit
+to understand this correction, which is applied only near sunrise and
+sunset.
+.PP
+The
 .I \-of
 or
 .I \-od
@@ -178,5 +206,6 @@ Ian Ashdown wrote most of the code,
 based on Jean-Jacques Delaunay's original gendaylit(1) implementation.
 Greg Ward wrote the final parameter parsing and weather tape conversion.
 .SH "SEE ALSO"
-dctimestep(1), genBSDF(1), gendaylit(1), gensky(1), genskyvec(1),
-rcollate(1), rcontrib(1), rfluxmtx(1), xform(1)
+dctimestep(1), genBSDF(1), gendaylit(1), gensdaymtx(1), gensky(1),
+genskyvec(1), genssky(1),
+rcollate(1), rcontrib(1), rfluxmtx(1), rmtxop(1), xform(1)