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Comparing Geo-LatLon2Place/bin/geo-latlon2place-makedb (file contents):
Revision 1.3 by root, Tue Mar 15 07:33:40 2022 UTC vs.
Revision 1.4 by root, Wed Mar 23 07:10:53 2022 UTC

… …
206 206
207my $torad = (atan2 1,0) / 90; 207my $torad = (atan2 1,0) / 90;
208 208
209my $boxes = int 6378 * 2 * 2 * (atan2 1,0) / $km; # equator radius / cell size 209my $boxes = int 6378 * 2 * 2 * (atan2 1,0) / $km; # equator radius / cell size
210 210
211open my $fh, "<:perlio", $ARGV[0]; 211open my $fh, "<:perlio", $ARGV[0]
212 or die "$ARGV[0]: $!\n";
212 213
213my @grid; 214my @grid;
214 215
215while (<$fh>) { 216while (<$fh>) {
216 my ($lat, $lon, $w, $payload) = $extract->() 217 my ($lat, $lon, $w, $payload) = $extract->()
… …
228 229
229 # we use 16 bit for lat/lon, 8 bi8t for the weight, BER-id, counted name and CC 230 # 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 push @{ $grid[$y][$x] }, pack "s< s< C C/a*", $lat * 32767 / 90, $lon * 32767 / 180, $w, $payload;
231} 232}
232 233
233my ($max, $sum, $cnt); 234#############################################################################
235# write gridded data out
234 236
235open my $cdb, ">", $ARGV[1] 237open my $cdb, ">", $ARGV[1]
236 or die; 238 or die "$ARGV[1]: $!\n";
237Geo::LatLon2Place::cdb_make_start fileno $cdb 239Geo::LatLon2Place::cdb_make_start fileno $cdb
238 and die "cdb_make_start failure"; 240 and die "cdb_make_start failure";
239 241
240Geo::LatLon2Place::cdb_make_add "", pack "a4VVV", "SRGL", 2, $km, $boxes; 242Geo::LatLon2Place::cdb_make_add "", pack "a4VVVV", "SRGL", 2, $km, $boxes, time;
241 243
242for my $y (0 .. $#grid) { 244#############################################################################
245# now we walk the grid using a hilbert curve to increase locality when querying
246
247my ($max, $sum, $cnt); # statistics
248
249my ($x, $y) = (-1, 0);
250
251sub step { # move one step into $_[0] direction: 0 x++, 1 y++, 2 x--, 3 y--
252 ($_[0] & 1 ? $y : $x) += 1 - ($_[0] & 2);
253
254 # write cell at $x,$y, if any
243 my $r = $grid[$y]; 255 my $c = $grid[$y][$x]
244 for my $x (0 .. $#$r) { 256 or return;
245 my $c = $r->[$x]
246 or next;
247 257
258 undef $grid[$y][$x]; # for paranoia check
259
248 # statistics 260 # statistics
249 $sum += scalar @$c; 261 $sum += scalar @$c;
250 $cnt++; 262 $cnt++;
251 $max = [(scalar @$c), $x, $y] if @$c > $max->[0]; 263 $max = [(scalar @$c), $x, $y] if @$c > $max->[0];
252 264
253 Geo::LatLon2Place::cdb_make_add 265 Geo::LatLon2Place::cdb_make_add
254 +(pack "s< s<", $x, $y), 266 +(pack "s< s<", $x, $y),
255 +(join "", @$c) 267 +(join "", @$c)
256 and "cdb_make_add failure"; 268 and "cdb_make_add failure";
257 }
258} 269}
270
271sub hilbert;
272sub hilbert { # order dir rot
273 my $order = $_[0] >> 1
274 or return;
275
276 hilbert $order, $_[1] + $_[2], -$_[2]; step $_[1] + $_[2];
277 hilbert $order, $_[1] , $_[2]; step $_[1] ;
278 hilbert $order, $_[1] , $_[2]; step $_[1] - $_[2];
279 hilbert $order, $_[1] - $_[2], -$_[2];
280}
281
282step 0; # move to 0,0
283hilbert @grid * 2, 0, 1;
284
285# paranoia-check, make sure we wrote out all cells
286for (@grid) {
287 grep $_, @$_
288 and die;
289}
290
291#############################################################################
259 292
260Geo::LatLon2Place::cdb_make_finish 293Geo::LatLon2Place::cdb_make_finish
261 and die "cdb_make_finish failed"; 294 and die "cdb_make_finish failed";
262close $cdb; 295close $cdb;
263 296

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