#!/usr/bin/perl -w # (C) Copyright 2010, met.no # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA # 02110-1301, USA. # pod included at end of file use strict; use Getopt::Long; use Pod::Usage qw(pod2usage); use constant DEFAULT_TABLE_PATH => '/usr/local/lib/bufrtables'; my $BUFRDUMP = 'bufrdump'; # You should add path if bufrdump is # installed in a non-standard place # Parse command line options my %option = (); GetOptions( \%option, 'help', 'tablepath=s', # Set BUFR table path 'filter=s', # Decode observations meeting the filter criteria specified only 'param=s', # Decode/print specified parameters only 'csv', # Use CSV format for printing 'delimiter=s', # Choose the delimiter for the CSV format 'sort', # Sort on stationid (wmonr/nationalnr/call_sign/buoy_id/aircraft/wigosid) 'sort_on=s', # Sort on specified parameter 'station=s', # Filter on list of stations 'transform=s', # Do the transformations in <transformation file> 'lon1=i', 'lat1=i', 'lon2=i', 'lat2=i', 'obstype=s', # Force observation type ) or pod2usage(-verbose => 0); # User asked for help pod2usage(-verbose => 1) if $option{help}; # Make sure there is at least one input file pod2usage(-verbose => 0) unless @ARGV; # --csv can only be used together with --param pod2usage(-verbose => 0) if $option{csv} && !$option{param}; # Prevent ECMWF software from printing table info $ENV{PRINT_TABLE_NAMES} = 'false'; # Set BUFR table path environment variable used by bufrdump if ($option{tablepath}) { # Command line option --tablepath overrides all $ENV{BUFR_TABLES} = $option{tablepath}; } elsif (!$ENV{BUFR_TABLES}) { $ENV{BUFR_TABLES} = DEFAULT_TABLE_PATH; } # ECMWF software requires trailing '/' in bufrpath $ENV{BUFR_TABLES} .= '/' if substr($ENV{BUFR_TABLES},-1) ne '/'; die "Directory for BUFR tables: $ENV{BUFR_TABLES} does not exist" if ! -d $ENV{BUFR_TABLES}; my $obstype = $option{obstype} ? "--obstype $option{obstype}" : ''; my $filt = $option{filter} ? "$option{filter}" : ''; my $lon1 = $option{lon1} ? "--lon1 $option{lon1}" : ''; my $lat1 = $option{lat1} ? "--lat1 $option{lat1}" : ''; my $lon2 = $option{lon2} ? "--lon2 $option{lon2}" : ''; my $lat2 = $option{lat2} ? "--lat2 $option{lat2}" : ''; my $del = $option{delimiter} ? "$option{delimiter}" : ';'; my $delimiter = $option{delimiter} ? "--delimiter $del" : ''; # Any filter criteria provided? my ($filter, $criteria_ref, $num_alt_ref) = get_filter_conditions($filt); # Any specific stations requested? my ($req_id, $req_stn_ref) = get_requested_stations($option{station}); # Any specific parameters specified? my ($params_ref, $forced_params_ref) = get_params($option{param}); my $csv = $option{csv} ? 1 : 0; # First line in CSV should be the parameters print join($del, @$params_ref) . "\n" if $csv; # Any transformations of units specified? my $transform_file = $option{transform} ? $option{transform} : 0; my $transform_ref = read_transformation_file($transform_file); # Any sorting requested? my $sort = $option{sort} ? 1 : 0; my $sort_on = $option{sort_on} ? $option{sort_on} : ''; # What kind of sorting is required (if any)? ($sort_on, my $by) = get_sort_method($sort_on, $sort); # Loop for processing of BUFR input files my %data_of = (); foreach my $inputfname (@ARGV) { # Dump the content of the BUFR file using the Fortran program $BUFRDUMP my $fortran_options = "$obstype $filter $lon1 $lat1 $lon2 $lat2"; my $dump = `$BUFRDUMP $fortran_options $inputfname`; die if $?; # Reason for bufrdump failing should have been printed to STDERR # Then process the output from the dump my @lines = split /\n/, $dump; # Add an empty line to simplify processing push @lines, ''; my $stnid = ''; # Skip first (blank) line shift @lines; my @lines_to_print; my %msg; # Hash with parameter name as key, parameter value as value LINE: while (defined(my $line = shift @lines)) { # Each new message starts with a blank line if ($line !~ /^\s*$/) { # Skip error messages from libbufr, which should start with space(s) next LINE if $line =~ /^\s+/; # Build up the message to be (possibly) printed my ($param, $value) = ($line =~ /^(.+)=\s*(.*?)\s*$/); # Know only of one case where next check is necessary: if # a CCITT IA5 value contains new line (\n) next LINE if !defined $value; if ($transform_file && $transform_ref->{$param}) { # Replace value with transformed value my $transform = $transform_ref->{$param}; $transform =~ s/\$x/$value/g; $value = eval $transform; die "Couldn't parse following transform:\n" . $transform . "\nReason:\n$@" if $@; $line =~ s/=.*/=$value/; } $msg{$param} = $value; push @lines_to_print, $line; } if ($line =~ /^\s*$/ or @lines == 0) { # A full message has been completed. Should it be printed? if ($filt && filter_obs(\%msg, $criteria_ref, $num_alt_ref)) { # Skip this message } elsif ($req_id && filter_station(\%msg, $req_id, $req_stn_ref)) { # Skip this station } else { # Print the message (or if --sort or --sort_on: save the message) my $txt = ''; if ($params_ref) { # Print the params in @$params_ref if exists in # message, in same order as in @$params_ref foreach my $name (@$params_ref) { if (exists $msg{$name}) { $txt .= $csv ? $msg{$name} . $del : "$name=$msg{$name}\n"; } elsif ($forced_params_ref->{$name}) { $txt .= $csv ? '-32767' . $del : "$name=-32767\n"; } elsif ($csv) { $txt .= $del; } } } else { foreach my $line2 (@lines_to_print) { $line2 =~ s/=\s+/=/; $txt .= $line2 . "\n"; } } if ($csv) { # Remove last $del for (1 .. length($del)) { chop $txt; } } if ($txt) { if ($sort) { # Sort wmonr before nationalnr before call # sign before buoy_id before aircraft before wigosid if ($msg{wmonr}) { $stnid = '00_' . $msg{wmonr}; } elsif ($msg{nationalnr}) { $stnid = '10_' . $msg{nationalnr}; } elsif ($msg{call_sign}) { $stnid = '20_' . $msg{call_sign}; } elsif ($msg{buoy_id}) { $stnid = '30_' . $msg{buoy_id}; } elsif ($msg{aircraft}) { $stnid = '40_' . $msg{aircraft}; } elsif ($msg{wigosid}) { $stnid = '50_' . $msg{wigosid}; } else { # Skip observation if no station identification found next LINE; } if ($sort_on) { my $val = exists $msg{$sort_on} ? $msg{$sort_on} : ''; my $key = $stnid . '|' . $val; $data_of{$key} = exists $data_of{$key} ? $data_of{$key} . "$txt\n" : "$txt\n"; } else { $data_of{$stnid} = exists $data_of{$stnid} ? $data_of{$stnid} . "$txt\n" : "$txt\n"; } } elsif ($sort_on) { my $val = exists $msg{$sort_on} ? $msg{$sort_on} : ''; $data_of{$val} = exists $data_of{$val} ? $data_of{$val} . "$txt\n" : "$txt\n"; } else { # No sorting. We can print the line immediately print $txt .= "\n" if $txt; } } $txt = ''; } # Finished message @lines_to_print = (); %msg = (); } } } # If sorting requested, we cannot print before now if ($sort && $sort_on) { for (sort $by keys %data_of) { print $data_of{$_}; } } elsif ($sort) { for (sort keys %data_of) { print $data_of{$_}; } } elsif ($sort_on) { # Print observations with missing value for the sort parameter lastly my $data_of_missing_value = $data_of{''} || ''; delete $data_of{''}; for (sort $by keys %data_of) { print $data_of{$_}; } print $data_of_missing_value if $data_of_missing_value; } # Read the filter conditions (if any). Return the filter option to be # used by bufrdump, the found criteria (if any) as well as the number # of succeeding alternatives for each criterium sub get_filter_conditions { my $filt = shift; return ('') if ! $filt; my $fortran_filter = ''; my @f; if ($filt =~ /,/) { # Argument to --filter is a comma separated list @f = split /,/, $filt; } else { # Argument to --filter is a file $fortran_filter = "--filter $filt"; open my $FILTER, '<', $filt or die "Cannot open $filt: $!"; # Skip the criteria meant for Fortran parsing, i.e. proceed to # first line following a blank line while (<$FILTER>) { last if $_ =~ /^\s*$/; } @f = <$FILTER>; close $FILTER or die "Cannot close $filt: $!";; } return ($fortran_filter) if !@f; # BUFR descriptor criteria only my @allowed_operators = ('=', '<', '<=', '>', '>=', '!=', '=~', '!~', ); my @criteria; my @num_alt; # Number of alternative criteria following this, # i.e. if line is '<cr1> | <cr2> | <cr3>' then # corresponding values in @num_alt will be 2,1,0 # Read the filter criteria meant for Perl parsing, skipping blank # lines and comment lines FILTERLINE: foreach my $line (@f) { $line =~ s/^\s+//; $line =~ s/\s+$//; next FILTERLINE if !$line || $line =~ /^#/; my @crit = split /\|/, $line; my $num = scalar @crit; foreach my $criterium (@crit) { $criterium =~ s/^\s+//; $criterium =~ s/\s+$//; if ($criterium ne '') { push @criteria, $criterium; push @num_alt, --$num; } } } return ($fortran_filter) if !@criteria; # Check that the criteria are properly formatted foreach my $criterium (@criteria) { # Naked parameter possibly preceded by '!' is ok next if $criterium =~ /^!?\w+$/; my $op = (split / +/, $criterium)[1]; if (!defined($op) or grep(/[+*?\\]/, $op) or !grep(/^$op$/, @allowed_operators) ) { print "Error in $filt:\ncriterium is badly formatted" . " or operator not supported:\n$criterium"; exit 1; } } return ($fortran_filter, \@criteria, \@num_alt); } # Read the parameters into @params, those preceded by an exclamation # mark also into %forced_params, and return references to these two. sub get_params { my $params = shift; return if ! $params; my @params; my %forced_params; if ($params =~ /,/) { # Argument to --params is a comma separated list my @p = split /,/, $params; foreach my $name (@p) { $name =~ s/^\s+//; $name =~ s/\s+$//; if ($name =~ /^!/) { $name = substr $name, 1; $forced_params{$name} = 1; } push @params, $name; } } else { # Argument to --params is a file open my $PARAM, '<', $params or die "Cannot open file $params: $!"; while (my $name = <$PARAM>) { # Skip blank lines and comment lines $name =~ s/^\s+//; $name =~ s/\s+$//; next if !$name || $name =~ /^#/; if ($name =~ /^!/) { $name = substr $name, 1; $forced_params{$name} = 1; } push @params, $name; } close $PARAM or die "Cannot close $params: $!"; } return \@params, \%forced_params; } sub read_transformation_file { my $transform_file = shift; return if !$transform_file; open my $TRANSFORM, '<', $transform_file or die "Cannot open $transform_file: $!"; # Read in the transformations, skipping blank lines and comment # lines my %transform_of; while (my $line = <$TRANSFORM>) { $line =~ s/^\s+//; $line =~ s/\s+$//; next if !$line || $line =~ /^#/; my ($param, $transform) = split /=/, $line, 2; die "Invalid transformation in $transform_file:\n$line\n" unless $transform; $param =~ s/\s+$//; $transform =~ s/^\s+//; $transform_of{$param} = $transform; } close $TRANSFORM or die "Cannot close $transform_file: $!"; return \%transform_of; } # Return true (1) if observation is to be filtered, i.e. does not # comply with at least one line in filter file, where each line is one # or more alternatives <param> or <param> <operator> <value> sub filter_obs { my $msg_ref = shift; my $criteria_ref = shift; my $num_alt_ref = shift; # gives the number of alternative # criteria still to be checked return unless $criteria_ref; my @ascii_params = qw(aircraft call_sign icao_id name obstime type wigosid); # Note that the loop counter $i might be changed in the loop for (my $i=0; $i < @{$criteria_ref}; $i++) { my $num_alt = $num_alt_ref->[$i]; my $criterium = $criteria_ref->[$i]; my ($f_param, $f_operator, $f_value) = split / +/, $criterium, 3; # First check for !$par, meaning $par should not be in the observation if (substr($f_param,0,1) eq '!') { $f_param = substr($f_param,1); # If parameter is present, criterium is not fullfilled if (exists $msg_ref->{$f_param}) { next if $num_alt; # More alternatives to check # Criterium not fulfilled and no more alternatives to # check. This observation should be filtered away return 1; } else { # Criterium fulfilled. No need to check alternative criteria $i += $num_alt if $num_alt; next; } } # If parameter not present, criterium is obviously not fullfilled if (not exists $msg_ref->{$f_param}) { next if $num_alt; return 1; } my $msg_value = $msg_ref->{$f_param}; # If a naked parameter criterium, we already know parameter is # present (as found in previous check), so criterium is fulfilled if (not defined $f_operator) { if ($num_alt) { # No need to check the alternative criteria $i += $num_alt; } next; } chomp $f_value; my $op; if ($f_operator eq '<' || $f_operator eq '<=' || $f_operator eq '>' || $f_operator eq '>=' || $f_operator eq '=~' || $f_operator eq '!~') { $op = $f_operator; } elsif ($f_operator eq '=' || $f_operator eq '!=') { if (grep {$_ eq $f_param} @ascii_params) { $msg_value =~ s/\s*$//; $op = ($f_operator eq '=') ? 'eq' : 'ne'; } else { $op = ($f_operator eq '=') ? '==' : '!='; } } else { die "Internal error: unknown operator '$f_operator'"; } # Some parameters might need special massaging if ($f_operator !~ /~/) { if ($f_param eq 'wmonr' || $f_param eq 'buoy_id') { # Make non octal by removing leading 0 $msg_value =~ s/^0+//; $f_value =~ s/^0+// if $f_value != 0; } elsif ($f_param eq 'nationalnr') { # Convert to a pure numerical value (float). For 001101 # State id only numbers between 100 and 699 are operational $msg_value =~ s/_0*/./; $f_value =~ s/_0*/./; } elsif ($f_param eq 'obstime') { # Convert to a pure numerical value (float) $msg_value =~ s/[-:]//g; $msg_value =~ s/ /./; $f_value =~ s/[-:']//g; $f_value =~ s/^ +//; $f_value =~ s/ +$//; $f_value =~ s/ /./; } elsif ($f_param eq 'name') { # Add or correct quoting to "" and ignore casing $msg_value = '"' . lc $msg_value . '"'; $f_value = lc $f_value; if ($f_value =~ /^'.*'$/) { $f_value =~ s/^'//; $f_value =~ s/'$//; } if ($f_value !~ /^".*"$/) { $f_value = '"' . $f_value . '"'; } } } my $condition = "$msg_value $op $f_value"; # Some values should be string values if ($f_operator =~ /~/) { $condition = "q{$msg_value} $op $f_value"; } elsif (grep {$_ eq $f_param} @ascii_params) { $condition = "q{$msg_value} $op q{$f_value}"; } # Finally, do the criterium check if (eval $condition) { # No need to check the remaining alternative criteria $i += $num_alt if $num_alt; next; } else { next if $num_alt; return 1; } } # All filter conditions have been fullfilled return 0; } # Return the type of station requested, and the station # identifications. Leave some leeway for how to list wmonr and # nationalnr (leading 0's might be omitted - added here) sub get_requested_stations { my $req_stations = shift; return if !$req_stations; die "Station list must start with 'wmonr=', 'nationalnr=', " . "'call_sign=', 'buoy_id=', 'aircraft=' or 'wigosid='" unless $req_stations =~ /^(wmonr=|nationalnr=|call_sign=|buoy_id=|aircraft=|wigosid=)/; my ($id, $rest) = split /=/, $req_stations; my @stations = split /,/, $rest; if ($id eq 'wmonr') { my @req_stn; foreach my $station (@stations) { # Turn $station into a 5 digit wmonr $station =~ s/^0+//; $station += 1000 if $station < 1000; $station = sprintf("%05d", $station); push @req_stn, $station; } return ($id, \@req_stn); } elsif ($id eq 'nationalnr') { my @req_stn; foreach my $station (@stations) { # Turn national station number into 10 digits my ($state_id, $national_id) = split /_/, $station; die "Uncorrected formatted station: '$station' in station list" if !defined $national_id or $national_id eq ''; $station = $state_id . '_' . sprintf("%010d", $national_id); push @req_stn, $station; } return ($id, \@req_stn); } else { return ($id, \@stations); } } # Return true (1) if observation does not contain one of the stations # listed in @$req_stn_ref (of type $req_id), i.e. if this observation # should be filtered away sub filter_station { my ($msg_ref, $req_id, $req_stn_ref) = @_; return 1 unless $msg_ref->{$req_id}; my $stn = $msg_ref->{$req_id}; return !grep { $_ eq $stn } @$req_stn_ref; } # When --sort_on is used, need to supply the sort method. Also returns # input parameter $sort_on with possible trailing '-' (or '+') # stripped off sub get_sort_method { my ($sort_on, $sort) = @_; return if !$sort_on; my $ascending_sort = 1; # A minus sign appended to the sort parameter means descending sort if ($sort_on =~ /-$/) { $ascending_sort = 0; chop $sort_on; } # Just in case someone adds a '+' to signify ascending sort if ($sort_on =~ /[+]$/) { chop $sort_on; } my @ascii_params = qw(aircraft call_sign icao_id obstime name type wigosid); my $lexical_sort = grep {$_ eq $sort_on} @ascii_params; my $sort_sub; if ($sort) { $sort_sub = sub { my ($stn_a, $val_a) = split /\|/, $a; my ($stn_b, $val_b) = split /\|/, $b; # Sort on stationid is always lexical and ascending my $cmp = $stn_a cmp $stn_b; if ($cmp) { return $cmp; } else { # Stationids are equal. Sort on value of sort_on parameter if ($lexical_sort) { if ($ascending_sort) { return $val_a cmp $val_b; } else { return $val_b cmp $val_a; } } else { # Numerical sort if ($ascending_sort) { return $val_a <=> $val_b; } else { return $val_b <=> $val_a; } } } } } else { # Sort restricted to sort_on parameter $sort_sub = sub { if ($lexical_sort) { if ($ascending_sort) { return $a cmp $b; } else { return $b cmp $a; } } else { # Numerical sort if ($ascending_sort) { return $a <=> $b; } else { return $b <=> $a; } } } } return ($sort_on, $sort_sub); } =pod =head1 SYNOPSIS bufrdump.pl <bufr file(s)> [--filter <filter file | filter list>] [--param <parameter file | parameter list> [--csv [--delimiter <del>]] [--sort] [--sort_on <parameter>[-]] [--station <station list>] [--transform <transformation file>] [--lon1 <x1>] [--lat1 <y1>] [--lon2 <x2>] [--lat2 <y2>] [--obstype <amdar|ocea|surface|sounding|sounding->] [--tablepath <path to BUFR tables>] [--help] =head1 DESCRIPTION Extracts BUFR messages from BUFR file(s) and prints section 4 as "parameter=value" lines. Calls the Fortran program bufrdump internally, so this program must be installed at the location set in variable $BUFRDUMP in source code. Execute without arguments for Usage, with option C<--help> for some additional info. See also L</https://wiki.met.no/bufr.pm/start> for examples of use. =head1 OPTIONS --filter <filter file | filter list> Decode observations meeting criteria in filter file or filter list only --param <parameter file | parameter list> [--csv [--delimiter <del>]] Print parameters in parameter file or comma separated list (e.g. wmonr,TA) only, in same order as they occur there. If using --csv possibly followed by --delimiter <del>, the parameters vill be printed using the CSV (comma-separated values) format, with the delimiter del (default is ';') --sort Sort the decoded observations on station identification; first stations with wmonr, then stations with nationalnr, call sign, buoy_id, aircraft or wigosid (others left out) --sort_on <parameter>[-] Sort the decoded observations on increasing values of parameter, or decreasing values if a '-' follows the parameter name. E.g. --sort_on TA- will sort on decreasing temperatures. Observations not containing the parameter at all will be printed lastly, except when --sort_on is combined with --sort (in which case sorting is done firstly on station identification, secondly on parameter with missing values printed first) --station <station list> Print observations for stations in station list only, e.g. wmonr=01384,01492 --transform <transformation file> Do the transformations of parameter values listed in transformation file --lon1 <x1> Decode observations with longitude >= x1 only --lat1 <y1> Decode observations with latitude >= y1 only --lon2 <x2> Decode observations with longitude <= x2 only --lat2 <y2> Decode observations with latitude <= y2 only x1,y1,x2,y2 should be decimal degrees --obstype <amdar|ocea|surface|sounding|sounding->] Force observation type. If this option is not set, will make an educated guess of observation type based on metadata in section 1 of each BUFR message --tablepath <path to BUFR tables> Set path to BUFR tables (overrides ENV{BUFR_TABLES}) --help Print this Usage (but you might instead prefer to use perldoc bufrdump.pl) Options may be abbreviated, e.g. --h or -h for --help. To avoid having to use the C<--tablepath> option, you are adviced to set the environment variable BUFR_TABLES to the directory where your BUFR tables are located (unless the default path provided by bufrdump.pl works for you). The lines in <parameter file>, or the comma separated values in <parameter list>, should be name of the parameters you want to be printed. For example, if you want only station identification and temperature to be printed for a BUFR SYNOP file, either supply wmonr,nationalnr,call_sign,TA as argument to --params, or supply a <parameter file> which should look like this: wmonr nationalnr call_sign TA If you want "parameter=value" to be printed also when value is missing in BUFR message, precede the parameter name with an exclamation mark (e.g. '!TA'). Missing values will then be displayed as -32767. If the argument to --param is a parameter list, you must prevent the shell from attaching special meaning to the exclamation mark by enclosing the list in single quotes. If the parameter list consists of one parameter only, a comma must be appended (e.g. 'wmonr,') because bufrdump.pl uses the appearence of comma to signal that this is not a filename but parameter name(s). If --csv is used in conjunction with --param, all values will be printed using the CSV format, with first line listing the parameters, and with missing fields printed as -32767 if the parameter is marked with '!' in parameter file or list. With the parameter file above, the listing may for example start like wmonr;nationalnr;call_sign;TA 01001;;;-1.5 ;;LF5U;9.0 You can choose another delimiter than semicolon by use of option --delimiter <del>, e.g. --csv --delimiter ',' Using --filter will decode only those observations that meet at least one of the BUFR descriptor criteria and all of the parameter criteria in <filter file>, where the BUFR descriptor criteria should come first in filter file followed by a blank line, then comes the parameter criteria which should match <param> or !<param> or <param> <operator> <value> where operator is one of =, !=, =~, !~, <, <=, > and >=. What follows =~ and !~ should be a Perl match regular expression. The parameter criteria may be phrased as alternatives by separating them with '|' on a single line. An example filter file is D: 001001 I2.2 01 D: 001001 I2.2 001002 I3.3 03 895 06 252 D: 001011 A9 LF5U type = Manned NN != 8 TA >= 5 TA < 9.5 RR_24 which decodes all observations with block number 01, two other specific wmo stations and one specific ship, where stations should be manned and have cloud cover with a value different from 8, and have temperature between 5 and 9.5 degrees Celsius, and contain precipitation for last 24 hours. Comment lines starting with # will be ignored. Another example: the filter file (starting with a blank line!) call_sign =~ /^L[A-N]..$/ obstime >= '2012-02-10 06:00:00' HW | HWA | PW | PWA FF > 10 | FG_010 > 10 will print only those ship observations for which the 4 character call_sign starts with 2 letters in the interval LA-LN, and having obstime larger or equal to the datetime given, and containing wave data (specifically: height or period of waves, manually or automatically measured), and with wind or 10 minutes gust more than 10 m/s. For convenience, when there are no BUFR descriptor criteria, you might provide the filter criteria on the command line. Example: --filter 'wmonr,TA > 0,RR_12 | RR_24, !FF' will decode only observations with wmonr, having positive temperature and containing precipitation for 12 or 24 hours and not reporting wind. If (like for --param) the filter list consists of one criterium only, a comma must be appended. To avoid the need of creating a filter file when observations for some few stations are requested, you can provide the stations in a comma separated list after option --station. Some examples: --station wmonr=01001,01152,01492 --station nationalnr=614_0050410003,637_108 --station call_sign=LF5U --station buoyid=64607,64609 --station aircraft=EU3421,JHCWUURA --station wigosid=0-376-0-511,0-20000-0-01492 You cannot mix different kinds of stations this way (before '=' you must choose either wmonr, nationalnr, call_sign, buoy_id, aircraft or wigosid). Note also that providing the stations in the BUFR descriptor part (first part) of the filter file will speed up execution time considerably, compared to using option --station. It is possible to combine --filter with --station if done with some care, e.g. specifying WMO block 01 and the required parameters in filter file, then the requested stations in station list. The --transform option is provided mainly to be able to use other units than what is default in bufrdump.pl. The transformation file should list the transformations wanted, one per line as <parameter> = <perl expression involving $x> where $x is original value of the parameter. For example, the following transformation file will display wind speed FF and wind gust FG in knots instead of m/s, rounded to one decimal, and cloud cover NN in % (instead of the default which is using WMO code table 2700, roughly counting octas): FF = sprintf("%.1f", $x*1.9438) FG = sprintf("%.1f", $x*1.9438) NN = int($x*12.5 + .5) If --transform is combined with --filter, the filter criteria should refer to the transformed values. E.g. if the above NN transform to % is to be applied for sky not all covered by clouds, you should use NN != 100 instead of NN != 8 in filter file. The --obstype option might be handy in some special cases, like when you are interested only in the surface part of oceanographic data (then use '--obstype surface'), or when you want to see only levels with vss>0 in high resolution radiosonde data (then use '--obstype sounding-'), or when data category and/or data sub-category in the BUFR messages have unusual values. =head1 AUTHOR Pål Sannes E<lt>pal.sannes@met.noE<gt> =head1 COPYRIGHT Copyright (C) 2010 met.no =cut