--- ray/doc/man/man1/gendaymtx.1	2018/05/24 15:21:15	1.8
+++ ray/doc/man/man1/gendaymtx.1	2019/06/25 00:09:45	1.10
@@ -1,4 +1,4 @@
-.\" RCSid $Id: gendaymtx.1,v 1.8 2018/05/24 15:21:15 greg Exp $
+.\" RCSid $Id: gendaymtx.1,v 1.10 2019/06/25 00:09:45 greg Exp $
 .TH GENDAYMTX 1 01/19/13 RADIANCE
 .SH NAME
 gendaymtx - generate an annual Perez sky matrix from a weather tape
@@ -9,6 +9,8 @@ gendaymtx - generate an annual Perez sky matrix from a
 ][
 .B "\-h"
 ][
+.B "\-A"
+][
 .B "\-d|\-s"
 ][
 .B "\-r deg"
@@ -53,6 +55,14 @@ Thus, an hourly weather tape for an entire year would
 yield 8760x3 (26280) values per output line (row).
 .PP
 The
+.I \-A
+option tells
+.I gendaymtx
+to generate a single column corresponding to an average sky
+computed over all the input time steps, rather than one
+column per time step.
+.PP
+The
 .I \-c
 option may be used to specify a color for the sky.
 The gray value should equal 1 for proper energy balance.
@@ -67,10 +77,12 @@ corresponding to a 20% gray.
 .PP
 The
 .I \-d
-option may be used to produce a sun-only matrix, with no sky contributions.
+option may be used to produce a sun-only matrix, with no sky contributions,
+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.
+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,