Scraping large pdf tables which span across multiple pages
I am trying to scrape PDF tables which span across multiple pages. I tried many things but the best seems to be pdftotext -layout as advised here. The problem is t
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Ok I took a shot at this and I think it will help, although I'm not sure what you want your final output to look like. I'm happy to work more on this so let me know if there are parts you need help with.
I started by downloading a PDF to Text application from CNET.
After installing, I checked these settings:
The important part here is we're using the physical layout option.
This gave us output that looks like this:
Taules de Dades de la Xarxa d’Estacions Meteorològiques Automàtiques 2 Anuari de dades meteorològiques 2012 / Servei Meteorològic de Catalunya 2 TEMPERATURA MITJANA MENSUAL ( ºC ) - 2012 COMARCA CODI i NOM EMA GEN FEB MAR ABR MAI JUN JUL AGO SET OCT NOV DES ANY Alt Camp VY Nulles 7,5 5,5 10,9 12,3 16,7 21,6 22,3 24,4 20,1 15,9 11,0 8,5 14,8 Alt Camp DQ Vila-rodona 7,9 5,6 11,0 12,0 16,6 21,6 22,0 24,3 19,9 15,8 11,0 8,6 14,7 Alt Empordà U1 Cabanes 8,2 6,5 11,7 12,6 17,5 22,0 23,1 24,4 20,4 16,6 11,8 8,3 15,3 Alt Empordà W1 Castelló d'Empúries 8,1 6,4 11,6 12,9 17,0 21,1 22,0 23,4 20,1 16,4 12,1 8,5 15,0 Alt Empordà VZ Espolla 9,0 6,7 12,4 12,7 17,8 22,0 23,3 24,8 20,9 16,7 12,0 8,9 15,6 [......] 3 Anuari de dades meteorològiques 2012 / Servei Meteorològic de Catalunya 2 TEMPERATURA MITJANA MENSUAL ( ºC ) - 2012 COMARCA CODI i NOM EMA GEN FEB MAR ABR MAI JUN JUL AGO SET OCT NOV DES ANY Baix Empordà DF la Bisbal d'Empordà 6,6 5,3 10,9 12,6 17,2 21,9 22,9 24,6 20,3 16,6 11,9 7,6 14,9 Baix Empordà UB la Tallada d'Empordà 6,1 5,2 10,7 12,3 16,6 21,3 22,2 23,8 19,7 15,8 11,7 7,6 14,4 Baix Empordà UC Monells 6,1 4,6 9,9 11,4 16,5 21,7 23,0 24,5 19,6 15,7 11,7 7,2 14,3 Baix Empordà UD Serra de Daró 6,3 5,3 10,6 12,3 16,8 21,6 22,7 24,3 20,3 16,6 12,2 7,7 14,8 [......] 4 Anuari de dades meteorològiques 2012 / Servei Meteorològic de Catalunya 2 TEMPERATURA MITJANA MENSUAL ( ºC ) - 2012 COMARCA CODI i NOM EMA GEN FEB MAR ABR MAI JUN JUL AGO SET OCT NOV DES ANY Maresme UQ Dosrius - PN Montnegre Corredor 7,2 4,6 10,8 10,7 15,8 20,4 20,8 23,4 18,6 15,1 10,7 7,8 13,9 Maresme WT Malgrat de Mar 7,4 5,4 11,0 13,0 16,7 21,5 22,8 24,6 20,9 17,2 12,9 8,8 15,2 Maresme DD Vilassar de Mar 10,1 7,5 12,6 13,9 17,9 22,4 23,7 25,7 22,1 18,4 13,8 10,8 16,6 Montsià US Alcanar 10,0 7,6 11,8 14,2 17,9 22,7 24,0 25,8 22,0 18,2 13,7 10,7 16,6 Montsià UU Amposta 9,6 7,5 12,1 14,3 18,3 22,8 23,5 25,3 21,6 18,0 13,1 10,8 16,4 [......]You can see the columns line up much better, but we also have headers and page numbers. Also the
COMARCAandi NOM EMAcolumns were variying length. We want to normalize this to fixed width columns.I wrote a Perl program to do normalize it, and it also combines tables with the same title, and only prints the headers at the top. It creates an output folder with all the files with the title as the file name.
Here's the code:
#!/bin/perl use strict; use warnings; use open qw(:std :utf8); use utf8; my $comarca; my $nom; my $print_headers; my $title = ""; my $fh; while(<>) { if ( !/Xarxa d’Estacions/ and !/Meteorològiques Automàtiques/ and !/Servei/ and !/^\s*\d+\s*$/ and !/^\s*$/ ) { chomp($_); if ( /^\s*2/ ) { #title s/^\s*2\s*//; if ( $title ne $_ ) { $title = $_; $print_headers = 1; } } elsif ( /COMARCA/ ) { #column headers my ($first_col, $second_col, @the_rest) = split(/(CODI +i NOM EMA *)/, $_); $comarca = length $first_col; $nom = length $second_col; if ( $print_headers ) { my $str = sprintf "%-50s %-50s %s\n", $first_col, $second_col, join("", @the_rest); write_string($str); $print_headers = 0; } } else { #data my ($one, $two, $three) = unpack("A${comarca}A${nom}A*", $_); my $str = sprintf "%-50s %-50s $three\n", $one, $two; write_string($str); } } } sub write_string { my $string = shift; my $file_name = $title; $file_name =~ s/[\/\\]//g; open ($fh, '>>', ".\/output_folder\/${file_name}.txt") or die "Couldn't open: $!"; print $fh $string; close ($fh); }There are still a few imperfections in the output (you'll see these when you run this), but I wanted to get some feedback on what output would work best for you. There is definitely more we can do to improve the code! The output directory tree looks like this:
Matt@MattPC ~/perl/pdftotext $ find . . ./convert.pl ./EMAtaules2012.txt ./output.txt ./output_folder ./output_folder/AMPLITUD TÈRMICA MITJANA MENSUAL ( ºC ) - 2012?.txt ./output_folder/AMPLITUD TÈRMICA MÀXIMA MENSUAL ( ºC ) - 2012?.txt ./output_folder/DIRECCIÓ DOMINANT DEL VENT - 2012?.txt ./output_folder/GRUIX MÀXIM MENSUAL DE NEU AL TERRA ( cm ) - 2012?.txt ./output_folder/HUMITAT RELATIVA MITJANA MENSUAL ( % ) - 2012?.txt ./output_folder/MITJANA MENSUAL DE LA HUMITAT RELATIVA MÀXIMA DIÀRIA ( % ) - 2012?.txt ./output_folder/MITJANA MENSUAL DE LA HUMITAT RELATIVA MÍNIMA DIÀRIA ( % ) - 2012?.txt [......]Where a file might look like this:
COMARCA CODI i NOM EMA GEN FEB MAR ABR MAI JUN JUL AGO SET OCT NOV DES ANY Alt Camp VY Nulles 7,5 5,5 10,9 12,3 16,7 21,6 22,3 24,4 20,1 15,9 11,0 8,5 14,8 Alt Camp DQ Vila-rodona 7,9 5,6 11,0 12,0 16,6 21,6 22,0 24,3 19,9 15,8 11,0 8,6 14,7 Alt Empordà U1 Cabanes 8,2 6,5 11,7 12,6 17,5 22,0 23,1 24,4 20,4 16,6 11,8 8,3 15,3 Alt Empordà W1 Castelló d'Empúries 8,1 6,4 11,6 12,9 17,0 21,1 22,0 23,4 20,1 16,4 12,1 8,5 15,0 Alt Empordà VZ Espolla 9,0 6,7 12,4 12,7 17,8 22,0 23,3 24,8 20,9 16,7 12,0 8,9 15,6 Alt Empordà D6 Portbou 9,6 5,5 12,7 12,5 17,4 21,5 22,9 24,4 19,8 17,0 12,3 10,1 15,5 [......]Headers are only at the top and all the columns line up. This one is
TEMPERATURA MITJANA MENSUAL ( ºC ) - 2012.I've been thinking of uploading more of the output to a file hosting site, but I don't know which would be a good one, suggestions?
Hope this helps you Tomas!
EDIT: Example of missing entries from AMPLITUD TÈRMICA MÀXIMA MENSUAL ( ºC ) - 2012:
Solsonès VP Pinós 1 3,1 26 16,9 13 16,7 15 16,6 17 19,2 11 19,6 24 20,4 17 19,1 01 17,5 16 16,5 06 13,1 08 13,9 24 20,4 17/07 Solsonès XT Solsona 22,2 25 22,2 09 20,1 16 18,6 06 15,3 07 18,2 23 22,2 09/08 Tarragonès VQ Constantí 1 6,4 19 21,9 23 19,7 11 12,9 07 17,4 23 17,2 21 15,1 18 14,2 18 18,0 15 15,1 02 14,9 07 16,0 10 21,9 23/02
Update
Updated scripts for processing the input file:
#!/bin/perl use strict; use warnings; use open qw(:std :utf8); use utf8; use charnames ':full'; my @column_lengths; my $print_headers; my $title = ""; my $fh; while(<>) { if ( !/Xarxa d’Estacions/ and !/Meteorològiques Automàtiques/ and !/Servei/ and !/^\s*\d+\s*$/ and !/^\s*$/ ) { s/[\r\n]+//g; s/ +\d+$//; if ( /^\s*2/ ) { #title s/^\s*2\s*//; if ( $title ne $_ ) { $title = $_; $print_headers = 1; } } elsif ( /COMARCA/ ) { #column headers my $comarca = (split(/(COMARCA *)/, $_))[1]; my $codi = (split(/(CODI *)/, $_))[1]; my $inomema = (split(/(i NOM EMA *) /, $_))[1]; my $the_rest = (split(/(i NOM EMA *) /, $_))[2]; my @rest = split(/( \w+ *)/, $the_rest); undef @column_lengths; push @column_lengths, length $comarca; push @column_lengths, length $codi; push @column_lengths, length $inomema; for (@rest) { if ( $_ ) { push @column_lengths, length $_; } } $column_lengths[-1] = "*"; if ( $print_headers ) { $print_headers = 0; write_string(join(";", unpack( "A" . join("A", @column_lengths), $_)) . "\n"); } } else { #data write_string(join(";", unpack( "A" . join("A", @column_lengths), $_)) . "\n"); } } } sub write_string { my $string = shift; my $file_name = $title; $file_name =~ s/[º]//g; $file_name =~ s/[^\w ]//g; $file_name =~ s/ +/ /g; $file_name =~ s/È/E/g; $file_name =~ s/À/A/g; $file_name =~ s/Ó/O/g; $file_name =~ s/Í/I/g; $file_name =~ s/Ç/C/g; open ($fh, '>>', ".\/output_folder\/${file_name}.txt") or die "Couldn't open: $!"; print $fh $string; close ($fh); }This one combines lines with the d.i. on the next line.
#!/bin/perl -i use strict; use warnings; my $last = <>; while(<>) { my @current_array = split(";", $_); if ( /^;+[ \t]+.d\.i\./ ) { my @last_array = split(";", $last); my @combined_array; #print "matches\n"; for my $element (@current_array) { if ( $element =~ /d\.i\./ ) { push @combined_array, $element; shift @last_array; } else { push @combined_array, $last_array[0]; shift @last_array; } } undef @current_array; @current_array = @combined_array; } $last = join ";", @current_array; print $last; }The output is in csv format with semicolon delimiters.
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