Sextractor for dummies - METU Astrophysics

46 CHAPTER 7: SE INPUT: THE CONFIGURATION FILE
Parameter Default Type Description
INTERP MAXXLAG 16 integers Maximum x gap (in pixels) allowed
(n ≤ 2)
in interpolating the input
INTERP MAXYLAG 16 integers
(n ≤ 2)
INTERP TYPE ALL keywords
(n ≤ 2)
image(s).
Maximum y gap (in pixels) allowed
in interpolating the input
image(s).
Interpolation method from the
variance-map(s) (or weightmap(s)):
NONE no interpolation,
VAR ONLY interpolate only the variancemap
(detection threshold),
ALL interpolate both the variancemap
and the image itself.
7.6.3 Memory Use
These are the parameters regulating the memory use of SE. To be honest, they are best kept at the
values in the ./sextractor2.2.2/config/default.sex file. 21 If you have the FLAGS output, then you
can check if there were any memory problems in the SE run. If so, this can be very bad for the
completeness of your catalog (it isn’t probably). In that case you might want to fiddle with the
MEMORY BUFSIZE and rerun.
Parameter Default Type Description
MEMORY BUFSIZE - integer Number of scanlines in the imagebuffer.
Multiply by 4 the
frame width to get equivalent
memory space in bytes.
MEMORY OBJSTACK - integer Maximum number of objects
that the objectstack can contain.
Multiply by 300 to get
equivalent memory space in
bytes.
MEMORY PIXSTACK - integer Maximum number of pixels
that the pixel-stack can contain.
Multiply by 16 to 32 to
get equivalent memory space in
bytes.
21 SE was programmed to do large images, even with limited memory and computing power. The only reason to
change these defaults is when you get something of a stack overflow.