--- ray/doc/man/man1/gendaymtx.1	2022/08/13 17:24:56	1.16
+++ ray/doc/man/man1/gendaymtx.1	2024/08/05 17:23:56	1.18
@@ -1,4 +1,4 @@
-.\" RCSid $Id: gendaymtx.1,v 1.16 2022/08/13 17:24:56 greg Exp $
+.\" RCSid $Id: gendaymtx.1,v 1.18 2024/08/05 17:23:56 greg Exp $
 .TH GENDAYMTX 1 01/19/13 RADIANCE
 .SH NAME
 gendaymtx - generate an annual Perez sky matrix from a weather tape
@@ -29,7 +29,9 @@ 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"
@@ -155,6 +157,15 @@ 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
@@ -190,5 +201,6 @@ 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)