[ViewVC] Annotation of: cvs/Geo-LatLon2Place/bin/geo-latlon2place-makedb

#!/opt/bin/perl

=head1 NAME

geo-latlon2place-makedb - generate database for use with Geo::LatLon2Place

=head1 SYNOPSIS

geo-latlon2place-makedb [OPTION]... inputfile.txt outputfile.cdb

=head1 DESCRIPTION

abc

=head1 OPTIONS AND ARGUMENTS

geo-latlon2place-makedb requires two arguments: a text file with geo data
and the name of the database file to be written.

By default, the input file is considered to be in geonames gazetteer
format, but this can be customized using B<--extract>.

=over

=item B<--cellsize> km (default C<20>, or C<10> for geonames-postalcodes)

The (minimum) size of a single grid cell in km - the data is binned into
cells of at least this size. It should not be larger than the search
radius.

=item B<--extract> C<geonames>|C<geonames-postalcodes>|perl...

The extraction method: the default is C<geonames>, which expects a
geonames database (L<https://download.geonames.org/export/dump/>, for
example F<DE.txt>, F<cities500.txt> or F<allCountries.txt>) and extracts
I<placename, countrycode> strings from it.

The method C<geonames-postalcodes> does the same, but for a geonames
postal code database L<https://download.geonames.org/export/zip>, and
extracts C<zip name, countrycopde> strings.

Lastly, you can specify a perl fragment that implements your own filtering
and extraction.

=back

=head1 FILTERING AND EXTRACTION

Record selection and the returned data are not fixed - you can filter your records
yourself and associate any (reasonably short, the maximum is a bit above 200 octets)
binary blob with a coordinate pair.

To do this, you have to provide a perl fragment that extracts latitude,
longitude, a weight and the associated data blob from an input line stored
in C<$_>. The file is opened using the C<:perlio> layer, so if your input
file is in UTF-8, so will be C<$_>.

For example, the following would expect an input file with space separated
latitude, longitude, weight and name, where name can contain spaces, which
is useful when you want to provide your own input data:

   geo-latlon2place-makedb --extract 'chomp; split / /, 4' input output

A slighly more verbose example expecting only latitude, longitude and a
name would be:

   geo-latlon2place-makedb --extract '
      chomp;
      my ($lat, $lon, $name) = split / /, 4;
      ($lat, $lon, 1, $name)
   ' input output

If you want to skip certain lines without adding anything to the database,
you can return nothing:

   geo-latlon2place-makedb --extract '
      chomp;
      my ($lat, $lon, $name) = split / /;
      return unless $lat < 0; # only add southern hemisphere points
      ($lat, $lon, 1, $name)
   ' input output

In general, the fragment should return either an empty list, or a
four-tuple with decimal latitude, longitude, a weight (integer 0..255)
and the binary data to be associated with the coordinate. Other than the
weight, these should be self-explaining. The weight is used during search
and will be multiplied to the square of the distance, and is used to make
larger cities win over small ones when the coordinate is somewhere between
them.

The standard extractors (C<geonames> and C<geonames-postalcodes>) provide
a UTF-8-encoded string as blob, but any binary data will do, for example,
if you want to associate your coordinate pairs with some short-ish
integer codes, you could do this:

   geo-latlon2place-makedb --extract '
      chomp;
      my ($lat, $lon, $id) = split / /, 4;
      ($lat, $lon, 1, pack "w", $id)
   ' input output

And later use C<unpack "w"> on the data returned by C<lookup>.

The C<geonames> filter looks similar to the following fragment, which
shows off some more filtering possibilities:

   my ($id, $name, undef, undef, $lat, $lon, $t1, $t2, $cc, undef, $a1, $s2, $a3, $a4, $pop, undef) = split /\t/;

   return if $t1 ne "P"; # only places

   # minimum population 200, or it is a populated place with no known population
   $pop => 200
      or ($pop eq "" and $t2 eq "PPL")
      or return;

   # skip certain places we are not interested in
   return if $t2 eq "PPLX"; # section of populated place
   return if $t2 eq "PPLW"; # destroyed populated place
   return if $t2 eq "PPLH"; # historical populated place
   return if $t2 eq "PPLQ"; # abandoned populated place

   # geonames has a lot of very long place names which aren't
   # actually place names, so ignore very long names
   60 > length $name
      or return;

   # we estimate a weight by dividing 25 by the radius of the place,
   # which we get by assuming a fixed population density of 5000 # people
   # per square km, # which is almost always a considerable over-estimate.
   # 25 and 5000 are pretty much made-up, feel free to improve and
   # send me the results.
   my $w = 25 / (1 + sqrt $pop / 5000);

   # administrative centers get a fixed low weight
   if ($t2 =~ /^PPLA(\d*)/) {
      $w = $1 || 1;
   }

   ($lat, $lon, $w, "$name, $cc")

=head1 AUTHOR

Marc Lehmann <schmorp@schmorp.de>

=cut

use common::sense;
use Getopt::Long;
use Geo::LatLon2Place ();
use Pod::Usage ();

GetOptions
   "help|h"     => sub { Pod::Usage::pod2usage -exittval => 0, verbose => 1 },
   "extract=s"  => \my $extract,
   "cellsize=i" => \my $km,
   or Pod::Usage::pod2usage
      -exitval => 1,
;

@ARGV == 2
   or die "need exactly two paths: inputfile.txt outputdatabase.cdb\n";

$extract ||= "geonames";

if ($extract eq "geonames") {
   $extract = sub {
      my ($id, $name, undef, undef, $lat, $lon, $t1, $t2, $cc, undef, $a1, $s2, $a3, $a4, $pop, undef) = split /\t/;

      return if $t1 ne "P"; # only places

      $pop => 200
         or ($pop eq "" and $t2 eq "PPL")
         or return;

      return if $t2 eq "PPLX"; # section of populated place
      return if $t2 eq "PPLW"; # destroyed populated place
      return if $t2 eq "PPLH"; # historical populated place
      return if $t2 eq "PPLQ"; # abandoned populated place

      # geonames has a lot of very long place names which aren't
      # actually place names, so ignore very long names
      60 > length $name
         or return;

      my $w = 25 / (1 + sqrt $pop / 5000);

      if ($t2 =~ /^PPLA(\d+)/) {
         $w = $1 || 1;
      }

      ($lat, $lon, $w, "$name, $cc")
   };
} elsif ($extract eq "geonames-postalcodes") {
   $km ||= 10;
   $extract = sub {
      my ($cc, $zip, $name, undef, undef, undef, undef, undef, undef, $lat, $lon, undef) = split /\t/;

      ($lat, $lon, 1, "$zip $name, $cc")
   };
} else {
   $extract = eval "#line 1 \"extract fragment\"\nsub { $extract; }";
   die "$@" if $@;
}

$km ||= 20;

my $torad = (atan2 1,0) / 90;

my $boxes = int 6378 * 2 * 2 * (atan2 1,0) / $km; # equator radius / cell size

open my $fh, "<:perlio", $ARGV[0];

my @grid;

while (<$fh>) {
   my ($lat, $lon, $w, $payload) = $extract->()
      or next;

   unless (255 >= length $payload) {
      $payload =~ s/([^(\x20-\x7e])/sprintf "\\x%02x", ord $1/ge;
      warn "payload too long, skipping: $payload\n";
      next;
   }

   my $blat = int $boxes * cos $lat * $torad; # can be 0, but does not matter
   my $x = int (($lon + 180) * $blat  / 360);
   my $y = int (($lat +  90) * $boxes / 180);

   # we use 16 bit for lat/lon, 8 bi8t for the weight, BER-id, counted name and CC
   push @{ $grid[$y][$x] }, pack "s< s< C C/a*", $lat * 32767 / 90, $lon * 32767 / 180, $w, $payload;
}

my ($max, $sum, $cnt);

open my $cdb, ">", $ARGV[1]
   or die;
Geo::LatLon2Place::cdb_make_start fileno $cdb
   and die "cdb_make_start failure";

Geo::LatLon2Place::cdb_make_add "", pack "a4VVV", "SRGL", 2, $km, $boxes;

for my $y (0 .. $#grid) {
   my $r = $grid[$y];
   for my $x (0 .. $#$r) {
      my $c = $r->[$x]
         or next;

      # statistics
      $sum += scalar @$c;
      $cnt++;
      $max = [(scalar @$c), $x, $y] if @$c > $max->[0];

      Geo::LatLon2Place::cdb_make_add
            +(pack "s< s<", $x, $y),
            +(join "", @$c)
         and "cdb_make_add failure";
   }
}

Geo::LatLon2Place::cdb_make_finish
   and die "cdb_make_finish failed";
close $cdb;

$max->[2] = $max->[2] * 180 / $boxes - 90;
my $blat = int $boxes * cos $max->[2] * $torad;
$max->[1] = $max->[1] * 360 / $blat - 180;
print "cell size: $km km, grid size: $boxes, non-empty cell count: $cnt\naverage cell size: ", int $sum/$cnt, ", maximum cell size: $max->[0] (at $max->[2] $max->[1])\n";

Revision:	1.3
Committed:	Tue Mar 15 07:33:40 2022 UTC (2 years, 2 months ago) by root
Branch:	MAIN
CVS Tags:	rel-0_9
Changes since 1.2:	+10 -13 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	#!/opt/bin/perl
2
3			=head1 NAME
4
5			geo-latlon2place-makedb - generate database for use with Geo::LatLon2Place
6
7			=head1 SYNOPSIS
8
9			geo-latlon2place-makedb [OPTION]... inputfile.txt outputfile.cdb
10
11			=head1 DESCRIPTION
12
13			abc
14
15			=head1 OPTIONS AND ARGUMENTS
16
17			geo-latlon2place-makedb requires two arguments: a text file with geo data
18			and the name of the database file to be written.
19
20			By default, the input file is considered to be in geonames gazetteer
21			format, but this can be customized using B<--extract>.
22
23			=over
24
25	root	1.3	=item B<--cellsize> km (default C<20>, or C<10> for geonames-postalcodes)
26	root	1.1
27			The (minimum) size of a single grid cell in km - the data is binned into
28			cells of at least this size. It should not be larger than the search
29			radius.
30
31			=item B<--extract> C<geonames>\|C<geonames-postalcodes>\|perl...
32
33			The extraction method: the default is C<geonames>, which expects a
34			geonames database (L<https://download.geonames.org/export/dump/>, for
35			example F<DE.txt>, F<cities500.txt> or F<allCountries.txt>) and extracts
36			I<placename, countrycode> strings from it.
37
38	root	1.2	The method C<geonames-postalcodes> does the same, but for a geonames
39			postal code database L<https://download.geonames.org/export/zip>, and
40			extracts C<zip name, countrycopde> strings.
41	root	1.1
42			Lastly, you can specify a perl fragment that implements your own filtering
43			and extraction.
44
45			=back
46
47			=head1 FILTERING AND EXTRACTION
48
49			Record selection and the returned data are not fixed - you can filter your records
50			yourself and associate any (reasonably short, the maximum is a bit above 200 octets)
51			binary blob with a coordinate pair.
52
53			To do this, you have to provide a perl fragment that extracts latitude,
54			longitude, a weight and the associated data blob from an input line stored
55			in C<$_>. The file is opened using the C<:perlio> layer, so if your input
56			file is in UTF-8, so will be C<$_>.
57
58			For example, the following would expect an input file with space separated
59			latitude, longitude, weight and name, where name can contain spaces, which
60	root	1.2	is useful when you want to provide your own input data:
61	root	1.1
62			geo-latlon2place-makedb --extract 'chomp; split / /, 4' input output
63
64			A slighly more verbose example expecting only latitude, longitude and a
65			name would be:
66
67			geo-latlon2place-makedb --extract '
68			chomp;
69			my ($lat, $lon, $name) = split / /, 4;
70			($lat, $lon, 1, $name)
71			' input output
72
73			If you want to skip certain lines without adding anything to the database,
74			you can return nothing:
75
76			geo-latlon2place-makedb --extract '
77			chomp;
78			my ($lat, $lon, $name) = split / /;
79			return unless $lat < 0; # only add southern hemisphere points
80			($lat, $lon, 1, $name)
81			' input output
82
83			In general, the fragment should return either an empty list, or a
84			four-tuple with decimal latitude, longitude, a weight (integer 0..255)
85			and the binary data to be associated with the coordinate. Other than the
86			weight, these should be self-explaining. The weight is used during search
87			and will be multiplied to the square of the distance, and is used to make
88			larger cities win over small ones when the coordinate is somewhere between
89			them.
90
91	root	1.2	The standard extractors (C<geonames> and C<geonames-postalcodes>) provide
92			a UTF-8-encoded string as blob, but any binary data will do, for example,
93			if you want to associate your coordinate pairs with some short-ish
94			integer codes, you could do this:
95
96			geo-latlon2place-makedb --extract '
97			chomp;
98			my ($lat, $lon, $id) = split / /, 4;
99			($lat, $lon, 1, pack "w", $id)
100			' input output
101
102			And later use C<unpack "w"> on the data returned by C<lookup>.
103
104			The C<geonames> filter looks similar to the following fragment, which
105			shows off some more filtering possibilities:
106	root	1.1
107			my ($id, $name, undef, undef, $lat, $lon, $t1, $t2, $cc, undef, $a1, $s2, $a3, $a4, $pop, undef) = split /\t/;
108
109			return if $t1 ne "P"; # only places
110
111			# minimum population 200, or it is a populated place with no known population
112			$pop => 200
113			or ($pop eq "" and $t2 eq "PPL")
114			or return;
115
116			# skip certain places we are not interested in
117			return if $t2 eq "PPLX"; # section of populated place
118			return if $t2 eq "PPLW"; # destroyed populated place
119			return if $t2 eq "PPLH"; # historical populated place
120			return if $t2 eq "PPLQ"; # abandoned populated place
121
122			# geonames has a lot of very long place names which aren't
123			# actually place names, so ignore very long names
124			60 > length $name
125			or return;
126
127			# we estimate a weight by dividing 25 by the radius of the place,
128	root	1.2	# which we get by assuming a fixed population density of 5000 # people
129			# per square km, # which is almost always a considerable over-estimate.
130	root	1.1	# 25 and 5000 are pretty much made-up, feel free to improve and
131			# send me the results.
132			my $w = 25 / (1 + sqrt $pop / 5000);
133
134			# administrative centers get a fixed low weight
135			if ($t2 =~ /^PPLA(\d*)/) {
136			$w = $1 \|\| 1;
137			}
138
139			($lat, $lon, $w, "$name, $cc")
140
141			=head1 AUTHOR
142
143			Marc Lehmann <schmorp@schmorp.de>
144
145			=cut
146
147			use common::sense;
148			use Getopt::Long;
149			use Geo::LatLon2Place ();
150			use Pod::Usage ();
151
152			GetOptions
153			"help\|h" => sub { Pod::Usage::pod2usage -exittval => 0, verbose => 1 },
154			"extract=s" => \my $extract,
155			"cellsize=i" => \my $km,
156			or Pod::Usage::pod2usage
157			-exitval => 1,
158			;
159
160			@ARGV == 2
161			or die "need exactly two paths: inputfile.txt outputdatabase.cdb\n";
162
163			$extract \|\|= "geonames";
164
165			if ($extract eq "geonames") {
166			$extract = sub {
167			my ($id, $name, undef, undef, $lat, $lon, $t1, $t2, $cc, undef, $a1, $s2, $a3, $a4, $pop, undef) = split /\t/;
168
169			return if $t1 ne "P"; # only places
170
171			$pop => 200
172			or ($pop eq "" and $t2 eq "PPL")
173			or return;
174
175			return if $t2 eq "PPLX"; # section of populated place
176			return if $t2 eq "PPLW"; # destroyed populated place
177			return if $t2 eq "PPLH"; # historical populated place
178			return if $t2 eq "PPLQ"; # abandoned populated place
179
180			# geonames has a lot of very long place names which aren't
181			# actually place names, so ignore very long names
182			60 > length $name
183			or return;
184
185			my $w = 25 / (1 + sqrt $pop / 5000);
186
187			if ($t2 =~ /^PPLA(\d+)/) {
188			$w = $1 \|\| 1;
189			}
190
191			($lat, $lon, $w, "$name, $cc")
192			};
193			} elsif ($extract eq "geonames-postalcodes") {
194	root	1.3	$km \|\|= 10;
195	root	1.1	$extract = sub {
196			my ($cc, $zip, $name, undef, undef, undef, undef, undef, undef, $lat, $lon, undef) = split /\t/;
197
198			($lat, $lon, 1, "$zip $name, $cc")
199			};
200			} else {
201			$extract = eval "#line 1 \"extract fragment\"\nsub { $extract; }";
202			die "$@" if $@;
203			}
204
205	root	1.3	$km \|\|= 20;
206
207			my $torad = (atan2 1,0) / 90;
208	root	1.1
209			my $boxes = int 6378 * 2 * 2 * (atan2 1,0) / $km; # equator radius / cell size
210
211			open my $fh, "<:perlio", $ARGV[0];
212
213			my @grid;
214
215			while (<$fh>) {
216			my ($lat, $lon, $w, $payload) = $extract->()
217			or next;
218
219	root	1.3	unless (255 >= length $payload) {
220	root	1.1	$payload =~ s/([^(\x20-\x7e])/sprintf "\\x%02x", ord $1/ge;
221			warn "payload too long, skipping: $payload\n";
222			next;
223			}
224
225	root	1.3	my $blat = int $boxes * cos $lat * $torad; # can be 0, but does not matter
226	root	1.1	my $x = int (($lon + 180) * $blat / 360);
227			my $y = int (($lat + 90) * $boxes / 180);
228
229			# we use 16 bit for lat/lon, 8 bi8t for the weight, BER-id, counted name and CC
230	root	1.3	push @{ $grid[$y][$x] }, pack "s< s< C C/a", $lat 32767 / 90, $lon * 32767 / 180, $w, $payload;
231	root	1.1	}
232
233			my ($max, $sum, $cnt);
234
235			open my $cdb, ">", $ARGV[1]
236			or die;
237			Geo::LatLon2Place::cdb_make_start fileno $cdb
238			and die "cdb_make_start failure";
239
240	root	1.3	Geo::LatLon2Place::cdb_make_add "", pack "a4VVV", "SRGL", 2, $km, $boxes;
241	root	1.1
242			for my $y (0 .. $#grid) {
243			my $r = $grid[$y];
244			for my $x (0 .. $#$r) {
245			my $c = $r->[$x]
246			or next;
247
248			# statistics
249			$sum += scalar @$c;
250			$cnt++;
251			$max = [(scalar @$c), $x, $y] if @$c > $max->[0];
252
253			Geo::LatLon2Place::cdb_make_add
254			+(pack "s< s<", $x, $y),
255			+(join "", @$c)
256			and "cdb_make_add failure";
257			}
258			}
259
260			Geo::LatLon2Place::cdb_make_finish
261			and die "cdb_make_finish failed";
262			close $cdb;
263
264			$max->[2] = $max->[2] * 180 / $boxes - 90;
265	root	1.3	my $blat = int $boxes * cos $max->[2] * $torad;
266	root	1.1	$max->[1] = $max->[1] * 360 / $blat - 180;
267			print "cell size: $km km, grid size: $boxes, non-empty cell count: $cnt\naverage cell size: ", int $sum/$cnt, ", maximum cell size: $max->[0] (at $max->[2] $max->[1])\n";
268