#!/usr/bin/perl

use strict;
use warnings;
use Text::CSV_XS;
use Data::Dumper;

my $loc = "location.csv";
my $trans = "transaction.csv";
my $csv = Text::CSV_XS->new();
my %locations;

# error margin
my $delta = 10;

sub lookup_name {
    my ($href, $lat, $long) = @_;

    for my $k (keys %$href) {
        my ($lat2, $long2) = @{$href->{$k}};

        return $k if ((abs($lat - $lat2) < $delta) && (abs($long - $lo
+ng2) < $delta));
    }

    return "Unknown";
}

open my $fh, "<", $loc or die "Can't open $loc: $!\n";

# skip header line
<$fh>;

while (my $rec = $csv->getline($fh)) {
    my ($lat, $long, $name) = (@$rec)[1, 2, 5];
    push @{$locations{$name}}, $lat, $long;
}
print Dumper( %locations );

$csv = Text::CSV_XS->new();
close($fh);
open $fh, "<", $trans or die "Can't open $trans: $!\n";

# skip header line
<$fh>;

while (my $rec = $csv->getline($fh)) {
    my @fields = @$rec;

    my ($lat, $long) = @fields[20, 21];
    my $name = lookup_name(\%locations, $lat, $long, $delta);

    {
        local $" = ", ";
        print "$name -> @fields\n";
    }
}
[download]

This assusmes you will have 2 csv files called location.csv and transaction.csv Output is:

Evans Marcross -> 174, 0, 291061000, 59, 141130, 104945, 105755, 3355,
+ 0, 255094551, 255094551, 5005, 2, 505, 3.0, 3.5, 00, 00, 00, 141130,
+ 5140596, 645572
Thomas And Ptns Somerset -> 175, 0, 250401500, 133, 141130, 110343, 11
+0858, 760, 0, 255102140, 255102140, 5005, 2, 505, 3.0, 3.2, 00, 00, 0
+0, 141130, 5141449, 647452
Thomas J  Newton House -> 176, 0, 250400800, 29, 141130, 115529, 12013
+0, 1695, 0, 255119079, 255119079, 5005, 2, 505, 3.7, 4.2, 00, 00, 00,
+ 141130, 5147668, 656139
[download]