public function inverse($p)
{
$x = $p->x;
$y = $p->y;
$L = atan(Sourcemap_Proj::sinh(($x - $this->xs) / $this->n2) / cos(($y - $this->ys) / $this->n2));
$lat1 = asin(sin(($y - $this->ys) / $this->n2) / Sourcemap_Proj::cosh(($x - $this->xs) / $this->n2));
$LC = Sourcemap_Proj::latiso(0.0, $lat1, sin($lat1));
$p->x = $this->lc + $L / $this->rs;
$p->y = Sourcemap_Proj::invlatiso($this->e, ($LC - $this->cp) / $this->rs);
return $p;
}
