--- ray/doc/man/man1/gendaymtx.1	2021/02/17 02:30:08	1.15
+++ ray/doc/man/man1/gendaymtx.1	2024/04/26 23:10:59	1.17
@@ -1,4 +1,4 @@
-.\" RCSid $Id: gendaymtx.1,v 1.15 2021/02/17 02:30:08 greg Exp $
+.\" RCSid $Id: gendaymtx.1,v 1.17 2024/04/26 23:10:59 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"
@@ -81,6 +83,10 @@ 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,
@@ -88,11 +94,7 @@ 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
@@ -153,6 +155,15 @@ or
 through
 .I xform(1)
 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