I agree that starting at 1 is more consistent than starting at 0, because OTB is based on GDAL and GDAL starts at 1 and some applications already start at 1 (BandMath) . What I meant is that IF you announce a Python-like syntax, THEN it must be consitent with Python
Le lundi 27 février 2017 11:33:38 UTC+1, Poughon Victor a écrit : > > My two cents on this: > > *Start at 0 or 1:* > While there are strong arguments to start indexing at zero ( > https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/EWD831.html), > I vote for starting at 1 because: > - OTB is used by non programmers > - QGIS and GDAL are 1 based > - Most sensors are 1 based ( > http://gis.stackexchange.com/questions/219886/is-it-convention-to-index-a-raster-band-from-1?atw=1 > ) > > *End-point inclusion* > I think I prefer the end point to be excluded because then: > - A:B has B-A elements in it > - It's possible to express the empty range (A:A) (perhaps that's not a > good thing?) > > just my 2 cents > > Victor Poughon > ------------------------------ > *De :* [email protected] <javascript:> [[email protected] > <javascript:>] de la part de Guillaume Pasero [[email protected] > <javascript:>] > *Envoyé :* lundi 27 février 2017 10:51 > *À :* [email protected] <javascript:> > *Objet :* Re: [otb-users] Re: Extended filename for band selection > > Dear Julien, > > Thanks for your feedback. > It is true that current syntax is somewhere in-between different standards. > About the use of "band[]" as general syntax, it would not be consistent > with other extended filenames : we always use "keyword=value". So, it > should be something like "band=[]". > > Regards, > Guillaume > > On 02/25/2017 10:41 AM, Julien Radoux wrote: > > Dear Guillaume, > > This would be usefull, thanks. I don't care about band or bands. for the > syntax, Python-like is nice, but then it is confusing not to start with > band 0 for the first band. maybe using [] would also make things clear. To > be more "pythonic", I would rather use bands[] with the python indices but > this is probably more difficult to parse. Also, in python, [2:4] would mean > bands with index 2 and 3 (not the 4), so this is not consistent. > > To conclude, Python-like is fine, but it would be very confusing if there > are too many differences. In your example, it makes me think of Matlab > indexing, which is fine but should be stated as such in the help (then use > "end" instead of -1 for the last band) > > For the last question, I do have some home made scripts that could benefit > from band selection in the extended filename. One application with a > standard filter would be the use of Meanshift segmentation where you only > want the smoothed mean value for one of the output bands (e.g. a NDVI band) > but you want to use more than one band as input for the mean shift > segmentation. > > > > Le vendredi 24 février 2017 17:25:37 UTC+1, Guillaume Pasero a écrit : >> >> Dear users, >> >> A new feature is in development to provide an extended filename for input >> band selection (see extended_band >> <https://git.orfeo-toolbox.org/otb.git/shortlog/refs/heads/extended_band>). >> A simple use-case is when you have a multi-channel image, and you want to >> process only the second band of this image using an OTB Application. With >> this feature you could do it like this : >> >> otbcli_MyApplication -in *"my_image.tif?band=2"* -out output.tif >> >> The current syntax (inspired by Python syntax) has already been >> implemented : >> >> - *band=r1,r2,...,rn* where each '*ri*' is a generic range >> - A generic range can be : >> - A single band index : '1' is the first band, for negative >> numbers the numbering is backward ( '*-1*' is the last band) >> - A range of bands, using the character ':' between optional start >> and end indexes : >> - '*3:*' means the 3rd band until the last one >> - '*:-2*' means the first band until the second to last >> - '*2:4*' means bands 2, 3 and 4 >> >> >> We would like to have your feedback on several points : >> >> - We will likely change the keyword "*band*" to plural "*bands*", no >> objection ? >> - Is the syntax clear / convenient / confusing ? >> - There can be a debate between 0-based and 1-based indexing for band >> numbers. At the moment, it is not uniform in OTB but we think that >> 1-based >> indexing should be the convention exposed to the user. >> - It is also possible to implement it on image writers, would it help >> ? What would be your use-cases ? >> >> Thanks for your feedback, >> >> Guillaume >> -- >> <http://www.c-s.fr> *Guillaume PASERO* >> Responsable technique >> *Business Unit ESPACE & GeoInformation - Département Payload Data & >> Applications* >> >> *CS Systèmes d'Information* >> Parc de la Grande Plaine - 5, Rue Brindejonc des Moulinais - BP 15872 >> 31506 Toulouse Cedex 05 - FRANCE >> +33 561 17 64 21 - [email protected] <http://UrlBlockedError.aspx> >> > -- > -- > Check the OTB FAQ at > http://www.orfeo-toolbox.org/FAQ.html > > You received this message because you are subscribed to the Google > Groups "otb-users" group. > To post to this group, send email to [email protected] > <javascript:> > To unsubscribe from this group, send email to > [email protected] <javascript:> > For more options, visit this group at > http://groups.google.com/group/otb-users?hl=en > --- > You received this message because you are subscribed to the Google Groups > "otb-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > For more options, visit https://groups.google.com/d/optout. > > > -- > <http://UrlBlockedError.aspx> *Guillaume PASERO* > Responsable technique > *Business Unit ESPACE & GeoInformation - Département Payload Data & > Applications* > > *CS Systèmes d'Information* > Parc de la Grande Plaine - 5, Rue Brindejonc des Moulinais - BP 15872 > 31506 Toulouse Cedex 05 - FRANCE > +33 561 17 64 21 - [email protected] <javascript:> > > -- > -- > Check the OTB FAQ at > http://www.orfeo-toolbox.org/FAQ.html > > You received this message because you are subscribed to the Google > Groups "otb-users" group. > To post to this group, send email to [email protected] > <javascript:> > To unsubscribe from this group, send email to > [email protected] <javascript:> > For more options, visit this group at > http://groups.google.com/group/otb-users?hl=en > --- > You received this message because you are subscribed to the Google Groups > "otb-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > For more options, visit https://groups.google.com/d/optout. > -- -- Check the OTB FAQ at http://www.orfeo-toolbox.org/FAQ.html You received this message because you are subscribed to the Google Groups "otb-users" group. 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