[gnuastro-commits] master df7cd772: Book: example of radial profile script with MakeProfile's customtable

[Mohammad Akhlaghi]

branch: master
commit df7cd772bf6dbbe3fd4f2238a3f98138d377b165
Author: Mohammad Akhlaghi <mohammad@akhlaghi.org>
Commit: Mohammad Akhlaghi <mohammad@akhlaghi.org>

    Book: example of radial profile script with MakeProfile's customtable
    
    Until now, the example within the description of MakeProfile's custom table
    only had an abstract (hand-written!) radial profile. In practice, this
    profile will most likely be made by a script like
    'astscript-radial-profile'. But there are some intricacies with using that
    script (in particular the oversampling).
    
    With this commit, to make it clear, a full script has been added to the
    description, allowing the readers to try and see the effect themselves.
    
    This issue was reported by Sepideh Eskandarlou.
    
    This fixes bug #65106.
---
 NEWS              |  3 +++
 doc/gnuastro.texi | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/NEWS b/NEWS
index 28b23576..78e7b817 100644
--- a/NEWS
+++ b/NEWS
@@ -224,6 +224,9 @@ See the end of the file for license conditions.
   - bug #65055: Columns of empty FITS tables (with no rows) read in reverse.
   - bug #65084: Fits program's --skycoverage prints connected numbers for
     cubes; found with help of Rahna Payyasseri Thanduparackal.
+  - bug #65106: Necessity of using --oversample with
+    astscript-radial-profile when a 2D profile is to be created with
+    '--customtable' of MakeProfile; reported by Sepideh Eskandarlou.
 
 
 
diff --git a/doc/gnuastro.texi b/doc/gnuastro.texi
index 9a80e294..cb0b31d3 100644
--- a/doc/gnuastro.texi
+++ b/doc/gnuastro.texi
@@ -32164,6 +32164,67 @@ $ astscript-fits-view image.fits --ds9scale=minmax
 
 Recall that if you want your image pixels to have the same values as the 
@code{MEAN} column in your profile, you should run MakeProfiles with 
@option{--mcolnocustprof}.
 
+In case you want to build the profile using @ref{Generate radial profile}, be 
sure to use the @option{--oversample} option of 
@command{astscript-radial-profile}.
+The higher the oversampling, the better your result will be.
+For example you can run the following script to see the effect (also see 
@url{https://savannah.gnu.org/bugs/?65106, bug 65106}).
+But don't take the oversampling too high: both the radial profile script and 
MakeProfiles will become slower and the precision of your results will decrease.
+
+@verbatim
+#!/bin/bash
+
+# Function to avoid repeating code: first generate a radial profile
+# with a certain oversampling, then build a 2D profile from it):
+# The first argument is the oversampling, the second is the suffix.
+gen_rad_make_2dprf () {
+
+    # Generate the radial profile
+    radraw=$bdir/radial-profile-$2.fits
+    astscript-radial-profile $prof -o$radraw \
+                            --oversample=$1 \
+                            --zeroisnotblank
+
+    # Generate the custom table format
+    custraw=$bdir/customtable-$2.fits
+    asttable $radraw --output=interval.fits \
+             -c'arith RADIUS sorted-to-interval',MEAN \
+            -o$custraw
+
+    # Build the 2D profie.
+    prof2draw=$bdir/prof2d-$2.fits
+    echo "1 $xc $yc 8 30 0 0 1 0 1" \
+       | astmkprof --customtable=$custraw \
+                   --mergedsize=$xw,$yw \
+                    --output=$prof2draw \
+                   --mcolnocustprof \
+                    --oversample=1 \
+                   --clearcanvas \
+                   --mode=img
+}
+
+# Directory to hold built files
+bdir=build
+if ! [ -d $bdir ]; then mkdir $bdir; fi
+
+# Build a Guassian profile in the center of an image to start with.
+prof=$bdir/prof.fits
+astmkprof --kernel=gaussian,2,5 -o$prof
+
+# Find the center pixel of the image
+xw=$(astfits $prof --keyvalue=NAXIS1 --quiet)
+yw=$(astfits $prof --keyvalue=NAXIS2 --quiet)
+xc=$(echo $xw | awk '{print int($1/2)+1}')
+yc=$(echo $yw| awk '{print int($1/2)+1}')
+
+# Generate two 2D radial profiles, one with an oversampling of 1
+# and another with an oversampling of 5.
+gen_rad_make_2dprf 1 "raw"
+gen_rad_make_2dprf 5 "oversample"
+
+# View the two images beside each other:
+astscript-fits-view $bdir/prof2d-raw.fits \
+                   $bdir/prof2d-oversample.fits
+@end verbatim
+
 @item --customtablehdu INT/STR
 The HDU/extension in the FITS file given to @option{--customtable}.