This is really good advice, thanks. I'll keep the list informed. Agus On Thu, Nov 8, 2018 at 10:38 AM Guillaume Pasero <[email protected]> wrote:
> Hi Agustin, > > The BandMath tool only processes the images of equal sizes. So I would go > with creating an image with repeated lines, and I think the VRT format can > do that. > > After a quick search here <https://www.gdal.org/gdal_vrttut.html>, I > think you can create : > > - a VRT with the size of A, > - put inside a single 'SimpleSource' which is your one-line image B > - set the 'DstRect' parameter to the full dimension, it will stretch > the one-line image to fit the full image > - you tell GDAL to use nearest neighbor interpolation : <SimpleSource > resampling="nearest"> > > Regards, > Guillaume > > On 11/05/2018 06:40 PM, Agustin Lobo wrote: > > In order to calculate reflectance from a multi-spectral radiance image > acquired with a linear scanner, I also have a 1-row array of white > reference values, > that is: > > multi-spectral image A: x rows, y cols, z bands > multi-spectral white reference image B: 1 row, y cols, z bands > > I would need to divide each row of A by B. > > In a simple notation: > res <- a > for(i in 1:nrow(a)){ > res[i,,] <- a[i,,]*b > } > > I'd like to this for relatively large images (x=969, y=640, z=224), > avoiding any loop if possible. > The most obvious strategy would be to create a b2 image by repeating the > row of b x times and then use the otb raster arithmetic for a/b2. But is there > an otb way to create such a b2? or perhaps another approach (I.e using > the BandMath tool?) > Thanks > Agus > > > > -- > <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] > > -- > -- > 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] > To unsubscribe from this group, send email to > [email protected] > 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]. > 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. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] 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]. For more options, visit https://groups.google.com/d/optout.
