1 files changed, 83 insertions, 0 deletions
diff --git a/man/prognosis.1 b/man/prognosis.1
index 8c28b60..75c276a 100644
--- a/man/prognosis.1
+++ b/man/prognosis.1
@@ -87,6 +87,36 @@ Restrict output to ASCII. Intended for SMS, where a single non-ASCII character
 forces the message from GSM\-7 (160 characters per segment) into UCS\-2 (70).
 The degree sign becomes the unit letter and Polish diacritics are transliterated.
 .TP
+.B \-svg
+Produce an SVG meteogram instead of the hourly table. See
+.BR METEOGRAM .
+.TP
+.BI \-o " PATH" ", " \-out " PATH"
+Write to
+.I PATH
+instead of standard output.
+.PP
+.RS
+If
+.I PATH
+is an existing directory, or ends in a separator (in which case it is created),
+a filename is generated from the place and the date, so repeated runs on
+different days do not overwrite each other:
+.IR krakow-pl-2026-08-27.svg .
+Otherwise
+.I PATH
+is a filename, gaining
+.B .svg
+or
+.B .txt
+if it has none. A single
+.B -
+means standard output.
+.PP
+Colour is omitted when writing to a file, whatever the terminal would have
+shown.
+.RE
+.TP
 .B \-config
 Print the path of the configuration file and exit.
 .TP
@@ -216,6 +246,59 @@ a string appended to each value.
 A custom name may not shadow a built-in column. A value the API does not supply
 renders blank rather than as zero: for an allergen, "no data" and "none" are
 different claims.
+.SH METEOGRAM
+.B \-svg
+writes a standalone SVG: three panels sharing one time axis \(em temperature
+with the apparent temperature dashed, precipitation as bars with the
+probability as a dashed line against its own right-hand axis, and relative
+humidity \(em over shaded night bands, with dates marked at midnight.
+.PP
+No plotting library or external program is involved: SVG is markup, so this
+works on a machine with no graphics tooling at all.
+.PP
+.in +4n
+.EX
+prognosis \-l Krakow \-d 2 \-svg meteogram.svg
+firefox meteogram.svg
+rsvg\-convert \-o meteogram.png meteogram.svg
+.EE
+.in
+.PP
+The meteogram requests the fields it needs regardless of
+.BR columns ,
+so it is complete even when the table shows none of them.
+.PP
+Not every viewer reads from a pipe.
+.BR feh (1)
+does, given
+.BR - ,
+and so does
+.BR chafa (1);
+.BR nsxiv (1)
+has no standard-input mode at all and prints its usage, which does not make the
+cause obvious. Write the file first with
+.B \-o
+for those:
+.PP
+.in +4n
+.EX
+prognosis \-l Krakow \-svg | feh -
+prognosis \-l Krakow \-svg | chafa
+prognosis \-l Krakow \-svg \-o ~/tmp && nsxiv ~/tmp/krakow-pl-*.svg
+.EE
+.in
+.PP
+Most viewers handle the file itself, including
+.BR nsxiv (1),
+.BR feh (1),
+.BR display (1)
+and any browser, or
+.BR chafa (1)
+to draw it inside the terminal.
+.BR convert (1)
+may fall back to ImageMagick's own SVG renderer, which drops the curves;
+.BR rsvg-convert (1)
+does not.
 .SH WARNINGS
 IMGW publishes every warning in Poland, each tagged with the TERYT codes of the
 powiats it covers. The coordinates are resolved to that code through GUGiK, so