Make contour regions from a 2-D image
dmcontour infile levels outfile [verbose] [clobber] [kernel] [mode]
`dmcontour' allows the user to generate a region file from a
2-dimensional image that can be used
to subsequently filter their data from contour levels in an input
image. A virtual image file created from a table file with dm
syntax can be used.
The region filters are created such that they include the
contour level and
everything above it -- including possibly other contour levels.
Only closed contours will generate regions.
For best results users should smooth their image prior to
running dmcontour. The actual region will be a polygon approximation
to the contour.
If the input image has a physical coordinate system (e.g. a
binned Chandra event file), the output is in the physical
coordinates of the image. This makes using the file as a
filter for event lists/tables, as well as images which have
physical coordinates preserved, easy. If an image that
doesn't have physical coordinates (e.g. an optical image) is
used to define the contour levels, the output is in logical
coordinates. It will be difficult to display these contours
on anything other than another image which is congruent to
the input image.
NB: The region fits file produced by dmcontour can be loaded
into ds9 directly. However, if you find a display full of excluded
regions, you may wish to make a simpler regions version by choosing
only one level, e.g. "dmcopy regions.fits[contour_level=10]
region10.fits".
dmcontour in_image.fits "1,5,10,20" out_region.fits
Will read in the image, "in_image.fits" and create an output
region file that has contour intervals for each of the
specified levels.
The output region file will have region filters that will
inlcude everything >
1, everything >
5, everything >
10, and
everything >
20.
The syntax to use this with another tool (for example to
extract a histogram/spectrum) would be:
infile="my_file[sky=region(out_region.fits[contour_level=1])]"
This will filter the "sky" vector column in "my_file" with
the contour level = 1 region in the file "out_region.fits"
Input file name.
The name of the input file. It can be a table with a DM
virtual file specficiation that makes it into an image, eg "[bin ...]"
The contour levels to define regions. Only closed contours
will generate regions.
This parameter can either be a comma separated list of
values or it can be a range of values. Do not include any spaces.
|
value1:value2:value3
|
Generate intervals from
value1 to value2 in steps of value3
|
|
:value2:value3
|
Generate intervals
from min(data) to value2 in steps of value3
|
|
value1::value3
|
Generate intervals from
value1 to max(data) in steps of value3.
|
|
::value3
|
Intervals from min(data) to
max(data) in steps of value3
|
Output file name
The name of the output FITS region file.
Parameter=verbose (integer not required default=0 min=0 max=5)
Controls amount of information to print (0-5).
Clobber output if it exists? [y/n]
Data Model kernel of output file.
- concept
-
subspace
- dm
-
dmimages,
dmimfiltering,
dmregions
- gui
-
firstlook,
prism
- tools
-
dither_region,
dmappend,
dmfilth,
dmimg2jpg,
dmimgcalc,
dmimghist,
dmimgpick,
dmimgthresh,
dmmakereg,
dmregrid,
get_sky_limits,
get_src_region,
tg_create_mask
|
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