This IDL facility provides a means to find the index of all pixels belonging to
a latitude strip defined by its bounds
Location in HEALPix directory tree: src/idl/toolkit/query_strip.pro
- HEALPix resolution parameter used to index the pixel list (scalar integer)
- colatitude lower bound in radians measured from North Pole
(between 0 and ).
- colatitude upper bound in radians measured from North Pole (between 0 and ). If
theta1< theta2, the pixels lying in [theta1,theta2]
are output, otherwise, the pixel lying in [0,
theta2] and those lying in [theta1, ] are output.
- on output: list of ordered index for the pixels found
in the strip. The RING numbering scheme is used unless the keyword NESTED is set.
(=-1 if the strip is too small and no pixel is found)
- on output: number of pixels in Listpix (=0 if no pixel is found).
- if set, the output list uses the NESTED numbering scheme
instead of the default RING
- if set, all the pixels overlapping (even partially)
with the strip are listed, otherwise only those whose
center lies within the strip are listed
- if set, the routine prints its documentation header and exits.
query_strip finds the pixels within the given strip in a selective way WITHOUT
scanning all the sky pixels. The numbering scheme of the output list and the
inclusiveness of the strip can be changed
This section lists the routines related to query_strip
- version 6.4 or more is necessary to run query_strip .
- conversion between angles and pixel index
- conversion between vector and pixel index
- render the list of pixels enclosed
respectively in a given disc, polygon and triangle
query_strip , 256, 0.75*!PI, !PI/5, listpix, nlist, /nest
Returns the NESTED pixel index of all pixels with colatitude in
[0,] and those with colatitude in [,]
Version 3.31, 2017-01-06