static void test_geohash_precision(void)
{
GBOX bbox;
GBOX bounds;
int precision = 0;
gbox_init(&bbox);
gbox_init(&bounds);
bbox.xmin = 23.0;
bbox.xmax = 23.0;
bbox.ymin = 25.2;
bbox.ymax = 25.2;
precision = lwgeom_geohash_precision(bbox, &bounds);
//printf("\nprecision %d\n",precision);
CU_ASSERT_EQUAL(precision, 20);
bbox.xmin = 23.0;
bbox.ymin = 23.0;
bbox.xmax = 23.1;
bbox.ymax = 23.1;
precision = lwgeom_geohash_precision(bbox, &bounds);
//printf("precision %d\n",precision);
CU_ASSERT_EQUAL(precision, 3);
bbox.xmin = 23.0;
bbox.ymin = 23.0;
bbox.xmax = 23.0001;
bbox.ymax = 23.0001;
precision = lwgeom_geohash_precision(bbox, &bounds);
//printf("precision %d\n",precision);
CU_ASSERT_EQUAL(precision, 7);
}
GBOX* gbox_new(uint8_t flags)
{
GBOX *g = (GBOX*)lwalloc(sizeof(GBOX));
gbox_init(g);
g->flags = flags;
return g;
}
Datum BOX2D_in(PG_FUNCTION_ARGS)
{
char *str = PG_GETARG_CSTRING(0);
int nitems;
double tmp;
GBOX box;
gbox_init(&box);
if (strstr(str,"BOX(") != str )
{
elog(ERROR,"box2d parser - doesnt start with BOX(");
PG_RETURN_NULL();
}
nitems = sscanf(str,"BOX(%lf %lf,%lf %lf)", &box.xmin, &box.ymin, &box.xmax, &box.ymax);
if (nitems != 4)
{
elog(ERROR,"box2d parser - couldnt parse. It should look like: BOX(xmin ymin,xmax ymax)");
PG_RETURN_NULL();
}
if (box.xmin > box.xmax)
{
tmp = box.xmin;
box.xmin = box.xmax;
box.xmax = tmp;
}
if (box.ymin > box.ymax)
{
tmp = box.ymin;
box.ymin = box.ymax;
box.ymax = tmp;
}
PG_RETURN_POINTER(gbox_copy(&box));
}
Datum BOX2D_in(PG_FUNCTION_ARGS)
{
char *str = PG_GETARG_CSTRING(0);
int nitems;
double tmp;
GBOX box;
int i;
gbox_init(&box);
for(i = 0; str[i]; i++) {
str[i] = tolower(str[i]);
}
nitems = sscanf(str,"box(%lf %lf,%lf %lf)", &box.xmin, &box.ymin, &box.xmax, &box.ymax);
if (nitems != 4)
{
elog(ERROR,"box2d parser - couldnt parse. It should look like: BOX(xmin ymin,xmax ymax)");
PG_RETURN_NULL();
}
if (box.xmin > box.xmax)
{
tmp = box.xmin;
box.xmin = box.xmax;
box.xmax = tmp;
}
if (box.ymin > box.ymax)
{
tmp = box.ymin;
box.ymin = box.ymax;
box.ymax = tmp;
}
PG_RETURN_POINTER(gbox_copy(&box));
}
/*
** Return a geohash string for the geometry. <http://geohash.org>
** Where the precision is non-positive, calculate a precision based on the
** bounds of the feature. Big features have loose precision.
** Small features have tight precision.
*/
char *lwgeom_geohash(const LWGEOM *lwgeom, int precision)
{
GBOX gbox;
GBOX gbox_bounds;
double lat, lon;
int result;
gbox_init(&gbox);
gbox_init(&gbox_bounds);
result = lwgeom_calculate_gbox(lwgeom, &gbox);
if ( result == LW_FAILURE ) return NULL;
/* Return error if we are being fed something outside our working bounds */
if ( gbox.xmin < -180 || gbox.ymin < -90 || gbox.xmax > 180 || gbox.ymax > 90 )
{
lwerror("Geohash requires inputs in decimal degrees.");
return NULL;
}
/* What is the center of our geometry bounds? We'll use that to
** approximate location. */
lon = gbox.xmin + (gbox.xmax - gbox.xmin) / 2;
lat = gbox.ymin + (gbox.ymax - gbox.ymin) / 2;
if ( precision <= 0 )
{
precision = lwgeom_geohash_precision(gbox, &gbox_bounds);
}
/*
** Return the geohash of the center, with a precision determined by the
** extent of the bounds.
** Possible change: return the point at the center of the precision bounds?
*/
return geohash_point(lon, lat, precision);
}
