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[gnuastro-commits] master 36fe3056 1/2: Book: correction of the name of

 From: Mohammad Akhlaghi Subject: [gnuastro-commits] master 36fe3056 1/2: Book: correction of the name of --pixelareaonwcs option Date: Thu, 1 Dec 2022 07:07:53 -0500 (EST)

branch: master
commit 36fe3056b628464706af13abd08f54b763b68486
Author: Elham Saremi <saremi_elham@yahoo.com>
Commit: Elham Saremi <saremi_elham@yahoo.com>

Book: correction of the name of --pixelareaonwcs option

Until now, the --pixareaonwcs is used 6 times in the book. While "astfits"
program doesn't recognise this option. The correct option is
--pixelareaonwcs.

With this commit, this option was corrected. Also, some minor typos are
fixed.
---
doc/gnuastro.texi | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/doc/gnuastro.texi b/doc/gnuastro.texi
index 65da31f0..840b3193 100644
--- a/doc/gnuastro.texi
+++ b/doc/gnuastro.texi
@@ -11827,7 +11827,7 @@ $astfits --write=MYKEY1,20.00,"An example keyword" --write=MYKEY2,fd ## Inspect individual pixel area taken based on its WCS (in degree^2). ## Then convert the area to arcsec^2 with the Arithmetic program. -$ astfits input.fits --pixareaonwcs -o pixarea.fits
+$astfits input.fits --pixelareaonwcs -o pixarea.fits$ astarithmetic pixarea.fits 3600 3600 x x -o pixarea_arcsec2.fits
@end example

@@ -12533,7 +12533,7 @@ Such images can be useful in understanding the
underlying pixel grid with the sa
After all, nothing beats visual inspection with tools you are familiar with.

@table @code
-@item --pixareaonwcs
+@item --pixelareaonwcs
Create a meta-image where each pixel's value shows its area in the WCS units
(usually degrees squared).
The output is therefore the same size as the input.

@@ -12550,11 +12550,11 @@ You may observe gradients after warping and can check
if they caused by the dist
Such gradients can happen due to distortions because the detectors pixels are
measuring photons from different areas on the sky (or the type of projection
you're seeing).
This effect is more pronounced in images covering larger portions of the sky,
for instance, the TESS
images@footnote{@url{https://www.nasa.gov/tess-transiting-exoplanet-survey-satellite}}.

-Here is an example usage of the @option{--pixareaonwcs} option:
+Here is an example usage of the @option{--pixelareaonwcs} option:

@example
# Check the area each 'input.fits' pixel takes in sky
-$astfits input.fits -h1 --pixareaonwcs -o pixarea.fits +$ astfits input.fits -h1 --pixelareaonwcs -o pixarea.fits

# Convert each pixel's area to arcsec^2
$astarithmetic pixarea.fits 3600 3600 x x \ @@ -12567,7 +12567,7 @@$ astarithmetic pixarea.fits \$pixarea / -o
pixarea_rel.fits
@end example

@item --edgesampling=INT
-Extra sampling along the pixel edges for @option{--pixareaonwcs}.
+Extra sampling along the pixel edges for @option{--pixelareaonwcs}.
The default value is 0, meaning that only the pixel vertices are used.
Values greater than zero improve the accuracy in the expense of greater time
and memory consumption.
With that said, the default value of zero usually has a good precision unless
the given image has extreme distortions that produce irregular pixel shapes.
@@ -20072,7 +20072,7 @@ However, deep astronomical data are usually built by
several exposures (images),
Each image is also taken by (slightly) shifting the telescope compared to the
previous exposure.
This shift is known as dithering''.
We do this for many reasons (for example tracking errors in the telescope,
high background values, removing the effect of bad pixels or those affected by
cosmic rays, robust flat pattern measurement, etc.@footnote{E.g.,
@url{https://www.stsci.edu/hst/instrumentation/wfc3/proposing/dithering-strategies}}).
-One of those etc.'' reasons is to correct for the Moir@'e pattern in the
final coadded deep image.
+One of those etc.'' reasons is to correct the Moir@'e pattern in the final

The Moir@'e pattern is fixed to the grid of the image, slightly shifting the
telescope will result in the pattern appearing in different parts of the sky.
Therefore when we later stack, or coadd, the separate exposures into a deep
image, the Moir@'e pattern will be decreased there.
@@ -20185,7 +20185,7 @@ Based on the dithering pattern, you want to select the
increased resolution such
@node Invoking astwarp,  , Moire pattern and its correction, Warp
@subsection Invoking Warp

-Warp an input image into a new pixel grid by pixel mixing (see
@ref{Resampling}).
+Warp will warp an input image into a new pixel grid by pixel mixing (see
@ref{Resampling}).
Without any options, Warp will remove any non-linear distortions from the
image and align the output pixel coordinates to its WCS coordinates.
Any homographic warp (for example, scaling, rotation, translation, projection,
see @ref{Linear warping basics}) can also be done by calling the relevant
option explicitly.
The general template for invoking Warp is:
@@ -20314,7 +20314,7 @@ See the description of @option{--gridfile} below for
more.
@cindex Aligning an image
WCS coordinates of the center of the central pixel of the output image.
Since a central pixel is only defined with an odd number of pixels along both
dimensions, the output will always have an odd number of pixels.
-When @option{--center} or @option{--gridfile} aren't given, the output will
have have the same central WCS coordinate as the input.
+When @option{--center} or @option{--gridfile} aren't given, the output will
have the same central WCS coordinate as the input.

Usually, the WCS coordinates are Right Ascension and Declination (when the
first three characters of @code{CTYPE1} and @code{CTYPE2} are respectively
@code{RA-} and @code{DEC}).
For more on the @code{CTYPEi} keyword values, see @code{--ctype}.
@@ -20519,14 +20519,14 @@ The HDU/extension of the reference WCS file specified
with option @option{--wcsf
Number of extra samplings along the edge of a pixel.
By default the value is @code{0} (the output pixel's polygon over the input
will be a quadrilateral (a polygon with four edges/vertices).

-Warp uses pixel mixing to derive the output pixel values, for a complete
introduction.
-See @ref{Resampling}, and in particular its later part on distortions.
+Warp uses pixel mixing to derive the output pixel values.
+For a complete introduction, see @ref{Resampling}, and in particular its later
part on distortions.
To account for this possible curvature due to distortion, you can use this
option.
For example, @option{--edgesampling=1} will add one extra vertice in the
middle of each edge of the output pixel, producing an 8-vertice polygon.
Similarly, @option{--edgesampling=5} will put 5 extra vertices along each
edge, thus sampling the shape (and possible curvature) of the output pixel over
an input pixel with @mymath{4+5\times4=24} vertice polygon.
Since the polygon clipping will happen for every output pixel, a higher value
to this option can significantly reduce the running speed and increase the RAM
usage of Warp; so use it with caution: in most cases the default
@option{--edgesampling=0} is sufficient.

-To visually inspect the curvature effect on pixel area of the input image, see
option @option{--pixareaonwcs} in @ref{Pixel information images}.
+To visually inspect the curvature effect on pixel area of the input image, see
option @option{--pixelareaonwcs} in @ref{Pixel information images}.

@item --checkmaxfrac
Check each output pixel's maximum coverage on the input data and append as the
`@code{MAX-FRAC}' HDU/extension to the output aligned image.

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