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Add a maptile_for_point() function for MySQL to work out which slippy

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map tile a given point lies in.
This commit is contained in:
Tom Hughes 2007-10-09 22:59:32 +00:00
parent e0fd80c428
commit 250466e58e
3 changed files with 46 additions and 13 deletions
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13
db/README
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@ -32,11 +32,6 @@ Run this command in the db/functions directory:
$ make
The above command should work for linux and most other Unix systems
that use ELF shared objects. For MacOS X you will need to do:
$ make libquadtile.dylib
Make sure the db/functions directory is on the MySQL server's library
path and restart the MySQL server. On linux the easiest way to do this
is to create /etc/ld.so.conf.d/osm.conf and place the path to the
@ -50,12 +45,8 @@ $ mysql -u <uid> -p openstreetmap
(change <uid> with appropriate username of administrative user eg. root )
> create function tile_for_point returns integer soname 'libquadtile.so';
> exit
or, for MacOS X:
> create function tile_for_point returns integer soname 'libquadtile.dylib';
> create function tile_for_point returns integer soname 'libmyosm.so';
> create function maptile_for_point returns integer soname 'libmyosm.so';
> exit
Creating database skeleton tables

7
db/functions/Makefile
View file

@ -7,8 +7,11 @@ else
LDFLAGS=-shared
endif
libquadtile.so: quadtile.o
cc ${LDFLAGS} -o libquadtile.so quadtile.o
libmyosm.so: quadtile.o maptile.o
cc ${LDFLAGS} -o libmyosm.so quadtile.o maptile.o
quadtile.o: quadtile.c ${QTDIR}/quad_tile.h
cc `mysql_config --include` -I${QTDIR} -fPIC -O3 -c -o quadtile.o quadtile.c
maptile.o: maptile.c
cc `mysql_config --include` -fPIC -O3 -c -o maptile.o maptile.c

39
db/functions/maptile.c Normal file
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@ -0,0 +1,39 @@
#include <my_global.h>
#include <my_sys.h>
#include <m_string.h>
#include <mysql.h>
my_bool maptile_for_point_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
{
if ( args->arg_count != 3 ||
args->arg_type[0] != INT_RESULT ||
args->arg_type[1] != INT_RESULT ||
args->arg_type[2] != INT_RESULT )
{
strcpy( message, "Your maptile_for_point arguments are bogus!" );
return 1;
}
return 0;
}
void maptile_for_point_deinit(UDF_INIT *initid)
{
return;
}
long long maptile_for_point(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
{
double lat = *(long long *)args->args[0] / 10000000.0;
double lon = *(long long *)args->args[1] / 10000000.0;
long long zoom = *(long long *)args->args[2];
double scale = pow(2, zoom);
double r_per_d = M_PI / 180;
unsigned int x;
unsigned int y;
x = floor((lon + 180.0) * scale / 360.0);
y = floor((1 - log(tan(lat * r_per_d) + 1.0 / cos(lat * r_per_d)) / M_PI) * scale / 2.0);
return (x << zoom) | y;
}