Pixel querying routines

query_disc(nside, vec, radius[, inclusive, ...])	Returns pixels whose centers lie within the disk defined by vec and radius (in radians) (if inclusive is False), or which overlap with this disk (if inclusive is True).
query_polygon(nside, vertices[, inclusive, ...])	Returns the pixels whose centers lie within the convex polygon defined by the vertices array (if inclusive is False), or which overlap with this polygon (if inclusive is True).
query_strip(nside, theta1, theta2[, ...])	Returns pixels whose centers lie within the colatitude range defined by theta1 and theta2 (if inclusive is False), or which overlap with this region (if inclusive is True).
boundaries(nside, pix[, step, nest])	Returns an array containing vectors to the boundary of the nominated pixel.