You need to be careful about the quotes - needed to prevent the shell
interfering with the strings sent to the program. You need to surround
the coords with double AND single quotes as in my example.
David
On 23 November 2010 16:40, Jean-Baptiste Marquette <[log in to unmask]> wrote:
> It seems not to be so simple, considering the message I got after the following command :
>
> MacBookJB:Downloads marquett$ wcstran lm04510tbr9j1546 "500.0, 500.0" framein=pixel frameout=sky
> !! No pixel coordinate 2 value (axis 2) supplied using parameter POSIN -
> ! '500.0'.
> Please supply a new PIXEL Domain position for parameter POSIN.
> POSIN - Position to be transformed /'500.0'/ >
>
> I created a lm04510tbr9j1546.sdf file using the command
>
> fits2ndf lm04510tbr9j1546.fits lm04510tbr9j1546
>
>
> Le 23 nov. 2010 à 04:42, David Berry a écrit :
>
>> On 23 November 2010 00:29, Tim Jenness <[log in to unmask]> wrote:
>>> On Nov 22, 2010, at 2:21 PM, Jean-Baptiste Marquette wrote:
>>>
>>>>
>>>> Le 22 nov. 2010 à 17:14, Tim Jenness a écrit :
>>>>
>>>>>>
>>>>>> • Are the QV keywords a standard for distortion ?
>>>>>>
>>>>>
>>>>> http://www.starlink.ac.uk/docs/sun5.htx/node7.html
>>>>>
>>>>> I'm sure David Berry, Pat Wallace or Norman Gray can comment further.
>>>>
>>>> I see. If I well understand, only Gaia/Starlink is able to deal with QVs. I checked that the WCSTools' xy2sky yields not accurate sky coordinates in the upper right corner of my image, while the Gaia Pick object function does. What is its command-line counterpart ?
>>
>> The WCSTRAN command in kappa will convert coordinates from one system
>> to another. For instance, to convert pixel coord (1.0,1.0) to the
>> current frame (presumably sky coords), do
>>
>> % kappa
>> % wcstran <ndf> '"1.0,1.0"' framein=pixel
>>
>> where "<ndf>" is the name of the image in NDF format. You can be
>> explicit about wanting sky coords by adding "frameout=sky" to the end
>> of the command. Note, starlink supports two forms of pixel coords, 1)
>> "pixel" - which are pixel offsets from a nominated "origin" position
>> within the array, and 2) "grid" - which are pixel offsets from the
>> bottom left corner of the image.
>>
>> There are a whole host of commands for using and manipulating WCS
>> within the KAPPA and ATOOLS packages.
>>
>>>
>>> All the Starlink packages will work fine (in particular KAPPA), as will the AST library itself. Translating pixel (GRID) coordinates to sky positions is pretty straightforward if you use Starlink (it's a single call to the astTran function in the AST library).
>>
>> The AST library has C, Fortran, Java and perl bindings. See
>> http://starlink.jach.hawaii.edu/starlink/AST
>>
>>
>>>> Standardization urgently needed...
>>
>> And has been for years!
>>
>>> The plan was for ASTROM to be modified once the FITS Paper IV standard was finalised. It hasn't been so there is very little that can be done about it. As I said though, maybe David or whoever (who are in the UK) can comment further.
>>
>> Maybe the time is coming for the community to adopt a de facto
>> standard. In the mean time, only applications based on the AST library
>> (which includes all the starlink apps) will intepret the QV headers.
>>
>> David
>
> ================================================
> Bien cordialement/Very truly yours/Mit freundlichen Gruessen,
> Jean-Baptiste Marquette
> Institut d'Astrophysique de Paris
> CNRS - UMR 7095
> Université Pierre & Marie Curie
> 98bis Bd Arago
> 75014 Paris - France
> ================================================
>
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