1.1 --- a/latlon-v0007.c	Sat Sep 24 01:23:11 2016 +0200
     1.2 +++ b/latlon-v0007.c	Sat Sep 24 14:42:22 2016 +0200
     1.3 @@ -820,10 +820,15 @@
     1.4    double min_dist = INFINITY;   /* minimum distance */
     1.5    /* distance is zero if point is contained in cluster */
     1.6    if (pgl_point_in_cluster(point, cluster, false)) return 0;
     1.7 -  /* calculate (approximate) square compression of meridians */
     1.8 -  /* TODO: use more exact formula based on WGS-84 */
     1.9 +  /* calculate approximate square compression of meridians */
    1.10    comp = cos((lat0 / 180.0) * M_PI);
    1.11    comp *= comp;
    1.12 +  /* calculate exact square compression of meridians */
    1.13 +  comp *= (
    1.14 +    (1.0 - PGL_EPS2 * (1.0-comp)) *
    1.15 +    (1.0 - PGL_EPS2 * (1.0-comp)) /
    1.16 +    (PGL_SUBEPS2 * PGL_SUBEPS2)
    1.17 +  );
    1.18    /* iterate over all entries */
    1.19    for (i=0; i<cluster->nentries; i++) {
    1.20      /* get properties of entry */