getAbove method
Gets the tile immediately to the north (above) of this tile.
Wraps around if at the northern boundary. Returns the northern neighbor tile
Implementation
Tile getAbove() {
int y = tileY - 1;
if (y < 0) {
y = getMaxTileNumber(zoomLevel);
}
return Tile(tileX, y, zoomLevel, indoorLevel);
}