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[aprssig] Changing visibility Weather Symbols

Robert Bruninga bruninga at usna.edu
Wed Apr 16 23:43:25 UTC 2008


WEATHER Groupies beware?

In the initiative to upgrade APRS symbols, we are wasting some
very valuable OVERLAYABLE symbol subgroups with a few nailed
down legacy weather symbols.  We are proposing to consolidate
some of these Weather symbols to open up much more space.  Since
this is the first time we have considered actually CHANGING some
symbol definitions, this can cause problems out there for some
users of some legacy systems.

That is why I am posting this plan to the APRS community.  If we
do this, XASTIR and UIVIEW will be able to download new symbol
definitions.  But some legacy clients that do not operate from
external symbol files will show the wrong symbols for these. If
users of those systems forsee some serious problems with the
re-arrangement of these symbols, let us know the specific impact
and your ideas for a workaround.. 

The symbols that are impacted are as follows:

First, consolidate all of the visibility symbols into the old
SMOKE symbol and change its meaning to "VISIBILITY", and then
differentiate them with the overlay characters.  

"\E"  (existing smoke) the symbol with no overlay
"HE"  (an H overlay) will mean Haze
"SE"  (an S overlay) will mean Smoke
"BE"  (a  B overlay) will mean Blowing Snow
"DE"  (a  D overlay) will mean blowing Dust or sand
"FE"  (an F overlay) will mean Fog

Another category is to expand the RAIN symbol to make it kinda
like lots of angled dots coming from the sky, but with an open
center so that we can use overlays for a number of common
PRECIPITATIONS.  The consolidations would be:

"\`" (existing Rain) would be the symbol with no overlay
"R`" (an R overlay) would mean Rain
"F`" (an F overlay) would mean Freezing Rain
"H`" (an H overlay) would mean Hail
"D`" (an D overlay) would mean Drizzle
"E`" (an E overlay) would mean slEEt
"S`" (an S overlay) would mean Snow
Etc. and other particulates coming from the sky

Next, I propose expanding the existing RAIN SHOWER "\I" symbol
to look like some kind of cloud symbol with specks in it that
can be overlayed. (It needs to look different from the next
CLOUD symbol). It can then consolidate these symbols:

"RI" (an R overlay) would mean Rain Shower
"SI" (an S overlay) would mean Snow shower
"LI" (an L overlay) would mean Lightening
Etc. and other things related to clouds

Next, I propose expanding the existing CLOUD symbol to allow
definition of any number of different types of cloud.  This
needs to also look like a cloud but a different shape and allow
for overlays  (Maybe this cloud is clear):

"\(" is the existing cloud symbol (would have no overlay)
"P(" with P overlay would mean partly cloudy
"W(" with W overlay would be a wall cloud
"F(" would be Funnel cloud, but the original "\f" will also be
retained for now

This free's up a lot of overlayable symbol GROUPS each of which
can suport up to 36 different overlays in each group for the
future:

#H for 36 new Hazards (was only Hail)
#[ for 36 new human symbols (was only Wall Cloud)
#B was only blowing snow
#b was only blowing dust/sand
#{ was only fog
#* was snow only
#: was hail only
#D was drizzle only
#F was freezing rain only
#e was sleet only
#G was only Snow shower
#J was only Lightening
#p was only partly cloudy

Of course future code can fully draw each of these overlays as
distinct special symbols in any way they want.  But Uiview uers
are stuck with only seeing overlays on basic group shapes for
now.

To keep the noise-to-signal rate down, I suggest replying only
if you have something of significance that will be impacted by
this proposal.  I especially want to hear from Dale Hugley who
is a resource for weather, and Stephen Smith who will have to
draw them for Uiview. And others with a stake in this...

Bob, WB4APR





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