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hotspot
This Fortran facility provides a means to find local extrema of
a map in HEALPix format. It also serves to illustrate the use of the
following parts of the HEALPix toolkit:
fast neighbour and extrema finding in the nested scheme,
in-place conversion between RING and NESTED pixel schemes
Location in HEALPix directory tree:
src/f90/hotspot/HotSpots.f90
FORMAT %
hotspot
QUALIFIERS
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infile =
- Defines the input map file.
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extrema_outfile =
- Defines the output map file.
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maxima_outfile =
- Defines the output ascii list of maxima.
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minima_outfile=
- Defines the output ascii list of minima.
DESCRIPTION
hotspot reads a healpix map in FITS format and generates the following outputs:
1) a HEALPix map in FITS format which is zero everywhere, except at
pixels which contain local extrema. These pixels have the same
values as in the input map.
2) an ASCII file which lists the pixel numbers and values of
maxima, and
3) an ASCII file which lists the pixel numbers and values of
minima.
The facility can be used in both an interactive
mode and a command mode, where command qualifiers
are fed to the facility using an input file.
Note the following limitations:
hotspot (and the toolkit neighbour finder which it uses) will
only work on maps with  .
DATASETS The following datasets are involved in the hotspot
processing.
| Dataset |
Description |
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None required |
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SUPPORT This section lists those routines and facilities (including those external to the Healpix distribution) which can assist in the utilisation of hotspot.
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synfast
- This HEALPix facility can generate a FITS format
sky map to be input to hotspot.
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map2gif
- This HEALPix Fortran facility can be used to visualise the
output map.
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mollview
- This HEALPix IDL facility can be used to visualise the
output map.
EXAMPLE # 1:
hotspot runs in interactive mode.
EXAMPLE # 2:
When `filename' is present, hotspot enters the non-interactive mode and parses
its inputs from the file `filename'. This has the following
structure: the first entry is a qualifier which announces to the parser
which input immediately follows. If this input is omitted in the
input file, the parser assumes the default value shown below.
If the equality sign is omitted, then the parser ignores the entry.
In this way comments may also be included in the file.
In this example, the file contains the following qualifiers:
infile = map.fits
extrema_outfile = pixlminmax.fits
maxima_outfile = maxima.dat
minima_outfile = minima.dat
hotspot reads in the map `map.fits' and generates
an output map with name `pixlminmax.fits', and two ASCII files,
`maxima.dat' and
`minima.dat'.
RELEASE NOTES
Initial release (HEALPix 0.90)
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Optional non-interactive operation. Proper FITS file support
for input and output maps. (HEALPix 1.00)
MESSAGESThis section describes error messages generated by hotspot
| Message |
Severity |
Text |
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can not allocate memory for array xxx |
Fatal |
You do not have
sufficient system resources to run this
facility at the map resolution you required.
Try a lower map resolution. |
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Eric Hivon
2010-06-18
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