#!/bin/sh 
#
# wxbg -- Get a surface weather map GIF and put it in the root window
#
# This shell script will get the current weather map GIF from a weather
# map server via anonymous ftp and put it in the root window (background) on
# your X terminal.  The weather map GIF shows station
# reports, fronts, isobars, and highs and lows.  You'll need to have a
# color display to show everything correctly, but if you only have a B&W
# monitor you can still get a current B&W satellite image.  European
# users can easily modify the script to get satellite pictures from
# METEOSAT-4 or METEOSAT-3 from Edinburgh.  See below for details.
#
# Requirements:  X and either xgifroot or xv
#
# If your machine supports personal crontabs then you can put
# something like the following in your crontab to get the latest 
# weather map every hour: 
#
#	20 * * * *  $HOME/bin/wxbg
#
# The SA maps seem to be ready by around 15 past the hour, but I use 20
# minutes to be sure I don't miss it.  The satellite pictures seem to
# take longer -- change the 20 to 55.
#
# Command line options: -f forces the thing, even if it does not look
# like you are running an X server. The -v flag is "verbose", it shows
# you what it is doing.  All other flags are passed to your XGIFROOT
# program.  Simply use the -display option to put the map on a machine
# different from yours.
#
# Note for Europe: The Edinburgh server only updates their pictures once
# a day, and they have a small machine which is easily overloaded, so
# please DON'T poll them every hour like this.  Just put wxbg in your
# .xinitrc instead, or have cron update the picture once a day.
#
# Disclaimer: I hope you find this useful for getting the "big picture",
# but don't forget to get a *real* weather briefing before you go flying.  
# I'm not responsible if you get yourself into trouble based on info 
# provided by wxbg.  [And I wish I didn't feel I had to include this
# disclaimer!]
#
# Eric Myers <myers@umich.edu>
# Department of Physics, University of Michigan, Ann Arbor
# @(#) $Id: wxbg,v 1.15 1999/07/26 19:35:15 myers Exp myers $
#======================================================================*
# SELECT AN FTP SERVER: suitable servers come and go or change names
# over the years, so you may need to tweak these settings:

# The server vmd.cso.uiuc.edu was discontinued sometime at the end
# of summer '93, and wuarchive.wustl.edu is overloaded.  wmaps.aoc.nrao.edu
# seems to be the best server as of 1/94, but you can change it here:
#SERVER=wmaps.aoc.nrao.edu  # NRAO stopped updating 31 Oct 97
#WXDIR=pub/wx		# subdirectory where the maps are kept
#PRE=sa			# Surface Analysis and Radar (precip)
#PRE=ci		  	# North American satellite image (B&W)
#FNAME="sfc_depict.gif"	# leave blank to have it construct SA name

# 20 Nov 97: Purdue seems the best bet
SERVER=wxp.atms.purdue.edu
# 26 Jul 1999: Purdue changed department name?
SERVER=wxp.eas.purdue.edu
WXDIR=web/surface
# FNAME="sfc_map.gif"	
FNAME="sfc_depict.gif"	

# Alternate server: University of Edinburgh (Scotland) Meteorology Dept.
# for satellite photos (Europe).  I have not checked this in a long while!
#SERVER=cumulus.met.ed.ac.uk		
#SERVER=129.215.168.19		# IP address, if your nameserver has problems
#WXDIR=images/gifs		# this is where the GIFs are kept
#FNAME=uk.vis.gif			# UK picture 
#FNAME=eur.vis.gif			# Europe picture 
#FNAME=world.vis.gif			# World picture
#FNAME=norden.vis.gif			# Scandinavia


# SELECT A DISPLAY PROGRAM:
# XGIFROOT is the program used to put a GIF in the root window.
# xgifroot is faster, but if you don't have it then it can also be
# done by an xv incantation.   [You can get xgifroot via anonymous ftp
# to lifshitz.ph.utexas.edu in /pub/graphics/src/xgifroot.tar.Z]
# Unfortnately xgifroot reads GIF87 format but not GIF89 format.
#
# Change paths as appropriate, and use a full path name if you intend to
# call wxbg from cron!

#XGIFROOT=/usr/local/bin/xgifroot	
#XGIFROOT="/usr/local/bin/xv -max -root -quit "
XGIFROOT="xv -max -root -quit "


######### End of Customization ########################################

# We need the ps command if we are to run as a cron job, to help
# detect a running X server.  But the ps command differs  between BSD
# and SYSV machines, so... 

if [ -d /usr/ucb ]	# seems to be BSD
then
  PSCMD="ps -x"
else			# maybe it's SYSV instead
  PSCMD="ps -ef"
fi

TMP=${TMP-"/usr/tmp"}		# a temporary workplace


# -- parse the command line arguments for flags 

FLAGS=""                # flags will be passed to XGIFROOT command
FORCE=N			# don't be so forceful...

while [ $# != 0 ]
do      case "$1" in
        -f)	FORCE=Y ;; # force it even if X does not appear to be running
	-v)	set -x ;;  # verbose 
        -d | -display)  shift; DISPLAY=$1 ;; 	# get display name
        -*)     FLAGS="$FLAGS $1" ;; 
	 *)  PRE=$1	   # command line argument sa or ci
        esac
        shift
done

# -- make sure an X server is running, or all is for naught.  If DISPLAY
#    is set then assume that it's cool.  Otherwise look for a server. (Add 
#    your own server name to the list if you don't see it here, or use -f.)

if [ "$DISPLAY" = "" -a "$FORCE" != "Y" ]; then
  X=`${PSCMD} | egrep "(xinit|xdm|dxsession|Xsgi|vuesession)" | grep -v grep`
  if [ -z "$X" ]; then 
    echo "Error: Can't open display: $DISPLAY " ; 
    exit 1 	
  fi
  DISPLAY=${DISPLAY-":0"}		# DISPLAY must be something
fi

# -- construct file name for current WX info, if FNAME not already specified

if [ "$FNAME" = "" ]; then
  timestamp=`date -u '+%m%d%H'`		# date & time as MMDDHH for file name
  FNAME=${PRE}${timestamp}.gif 		# e.g. SA071518.gif
fi

# -- go and get the GIF file from the server via anonymous ftp.
#    It will be called wxmap.gif in the $TMP directory, in case you
#    want to get at it some other way during the hour

cd $TMP
ftp -n $SERVER <<EOF >/dev/null 2>&1
user anonymous  -$USER@`hostname`
binary
cd $WXDIR
get $FNAME wxmap.gif
quit
EOF

# -- only view the file if we got it OK (i.e. it's there and not empty)

if [ -s wxmap.gif   ]; then
  ${XGIFROOT} -display $DISPLAY $FLAGS wxmap.gif  >/dev/null 2>&1
fi

exit 0