[ViewVC] Contents 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 *
#	Content
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	=item B<--cellsize> km (default C<20>, or C<10> for geonames-postalcodes)
26
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	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
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	is useful when you want to provide your own input data:
61
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, $name)
81	' input output
82
83	In general, the fragment should return either an empty list, or a
84	four-tuple with decimal latitude, longitude, a weight (integer 0..255)
85	and the binary data to be associated with the coordinate. Other than the
86	weight, these should be self-explaining. The weight is used during search
87	and will be multiplied to the square of the distance, and is used to make
88	larger cities win over small ones when the coordinate is somewhere between
89	them.
90
91	The standard extractors (C<geonames> and C<geonames-postalcodes>) provide
92	a UTF-8-encoded string as blob, but any binary data will do, for example,
93	if you want to associate your coordinate pairs with some short-ish
94	integer codes, you could do this:
95
96	geo-latlon2place-makedb --extract '
97	chomp;
98	my ($lat, $lon, $id) = split / /, 4;
99	($lat, $lon, 1, pack "w", $id)
100	' input output
101
102	And later use C<unpack "w"> on the data returned by C<lookup>.
103
104	The C<geonames> filter looks similar to the following fragment, which
105	shows off some more filtering possibilities:
106
107	my ($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	# 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	# 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	$km \|\|= 10;
195	$extract = sub {
196	my ($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	$km \|\|= 20;
206
207	my $torad = (atan2 1,0) / 90;
208
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	unless (255 >= length $payload) {
220	$payload =~ s/([^(\x20-\x7e])/sprintf "\\x%02x", ord $1/ge;
221	warn "payload too long, skipping: $payload\n";
222	next;
223	}
224
225	my $blat = int $boxes * cos $lat * $torad; # can be 0, but does not matter
226	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	push @{ $grid[$y][$x] }, pack "s< s< C C/a", $lat 32767 / 90, $lon * 32767 / 180, $w, $payload;
231	}
232
233	my ($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	Geo::LatLon2Place::cdb_make_add "", pack "a4VVV", "SRGL", 2, $km, $boxes;
241
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	my $blat = int $boxes * cos $max->[2] * $torad;
266	$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