docs: add example using reproject to change wcs resolution

[alasdairwilson]

Thoughts on this very simple upscaling example?

I also added a new piece of error handling to rebin as the current message when you use scale factors > 1 is misleading

(e.g. 2 is an integer factor)

[hayesla]

hmm sorry to be a stopper here, but should we really be encouraging people to upscale data? it may come across that you are getting "better" resolution which is not true? especially with an aia example?

I like idea having some docs to show functionality - how about downscaling?

[alasdairwilson]

Fair point, i've updated it to be simply "changing resolution" the context is apparently imaging spectroscopists do this, but at least one was doing it on the data array hence the motivation for how to do it while preserving wcs

…

On Tue, Nov 4, 2025 at 4:04 PM Laura Hayes ***@***.***> wrote: *hayesla* left a comment (sunpy/ndcube#893) <#893 (comment)> hmm sorry to be a stopper here, but should we really be encouraging people to upscale data? it may come across that you are getting "better" resolution which is not true? especially with an aia example? I like idea having some docs to show functionality - how about downscaling? — Reply to this email directly, view it on GitHub <#893 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AOMOKZTODNHPX7M6YEX2IF333DE7LAVCNFSM6AAAAACKVGA43WVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTIOBWG43TEMJSG4> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[Cadair]

I think to what @hayesla said we should talk about when to use this and when to use rebin here, and a big health warning etc.

[Cadair]

Suggested change

	image_data = fits.getdata(AIA_171_IMAGE)
	image_header = fits.getheader(AIA_171_IMAGE)
	image_data = fits.getdata(AIA_171_IMAGE, ext=1)
	image_header = fits.getheader(AIA_171_IMAGE, ext=1)