LatLon ll1 = projection.eastNorth2latlon(new EastNorth(east, north));
LatLon ll2 = projection.eastNorth2latlon(new EastNorth(east + 100 / pixelPerDegree, north));
LatLon ll3 = projection.eastNorth2latlon(new EastNorth(east + tileSize / pixelPerDegree, north + tileSize / pixelPerDegree));
double deltaLat = Math.abs(ll3.lat() - ll1.lat());
double deltaLon = Math.abs(ll3.lon() - ll1.lon());
int precisionLat = Math.max(0, -(int)Math.ceil(Math.log10(deltaLat)) + 1);
int precisionLon = Math.max(0, -(int)Math.ceil(Math.log10(deltaLon)) + 1);
String zoom = SystemOfMeasurement.METRIC.getDistText(ll1.greatCircleDistance(ll2));
String extension = "dat";