sl - Make a slice through an image and plot the results RWW & MWP
sl 10,-2 -4,6 Generate the data along a slice between the
two points (10,-2) and (-4,6) in image 1 and i
write it in the file 'slice' in your home
sl h:-2,2 v:1,5 ps:4 Make the slice but force the horizontal and
vertical scales to the specified limits.
Normally sl autoscales based on the extrema
of the data. Use plot symbol 4 (crosses)
instead of a line.
sl im:2 ovl: lt:0 add:3 Generate the data along the previous slice. Use
image 2, overlay the plot on the previous
plot using a dotted line. Add 3 to the y-values.
cr 2;sl x(0),y(0) x(1),y(1) fn:"slice1"
Make the slice, but use the cursor to
define the points. (If using a tek4014 window
in a 5620 see the note in 'da ?!'.) The data
will be put in the file slice1 in the current
directory. This is similar to the macro 'slli'
sl logy: fn:"/dev/null" make the plot using the logarithm of the image,
but don't write a file.
sl im:2 m: fact:1E4 Add an additional column from image 2 to an
existing slice file. Scale the data by 10000.
Note you can only merge once, since slice
assumes the existing file has four columns.
Sl will produce a plot of the values at the points in an image along a slice.
The default is a linear-linear plot but linear-log plot is also possible
(this does not affect the printed output described below.) Line types as
described in "fl" are available.
The normal execution writes out four columns for each point, suitable for
plotting with mongo or some other package. The first two are the x and y offset
positions relative to the center of the map (in map units). The third is the
distance from the first point and the fourth is the map value at that
point. An example follows:
14 -9 0 0.5162
13 -8 1.41 1.043
12 -8 2.24 1.474
11 -7 3.61 1.583
10 -7 4.47 2.169
9 -6 5.83 2.109
8 -6 6.71 3.088
7 -5 8.06 4.641
6 -5 8.94 5
Running sl again into the same file with the merge (m:) option but with
another image will add another column of data. For each position in
the existing file the value of the closest grid point of the new image
will be used. This will work best if the two images have the same
gridding. A copy of the original file (before merging) is kept in
"file".old (e.g., slice.old).
Each data value is multiplied by the scale factor. This is useful
since mongo doesn't scale data or to correct a map for beam efficiency,
'slli' is a macro in .GMACROS which will generate a slice along a
line between two cursor points.
This document was last updated on
Tue Oct 17 16:24:05 EDT 2000
by Marc W. Pound.