[R] Reading a TIFF file

[Julio Rojas]

Dear Uwe, find attached an small portion of the file I'm working with. ArcGIS values for this file are in the CSV file. They are a vector of all rows put together.

Thanks and regards.


--- El vie, 4/22/11, Uwe Ligges <ligges at statistik.tu-dortmund.de> escribió:

> De: Uwe Ligges <ligges at statistik.tu-dortmund.de>
> Asunto: Re: [R] Reading a TIFF file
> A: "Julio Rojas" <jcredberry at ymail.com>
> Cc: r-help at r-project.org
> Fecha: viernes, 22 de abril de 2011, 12:37 pm
> Unless you can provide a small
> reproducible example (say a very small 
> tiff including the values you got from the non-R software)
> it will be 
> hard to tell what is going on.
> 
> Uwe Ligges
> 
> 
> On 22.04.2011 11:23, Julio Rojas wrote:
> > Dear all, I have been trying to speed up a process we
> have been done in ArcGIS. We have to read a single layer
> TIFF (monochrome image) in . For this, I have used the
> "rtiff" package. After reading the TIFF file, I compared the
> raw values for each pixel that I have in ArcGIS to the ones
> obtained in R. In ArcGIS I have discrete values in the range
> 0..255, while in R I have continuous values between 0..1.
> This, in itself might not be a problem if the values
> obtained in R, times 255 would show the values obtained in
> ArcGIS, but this is not the case. The images are very
> different. I tried to settle matters using Photoshop, and
> the values there are completely different from the other two
> (using RGB, the K value (in CMYK) or the B value (in
> HSB))!!!
> >
> > Can somebody help me with this problem? Can I trust
> "rtiff"? Should I stick to a very slow process in ArcGIS?
> Why PS, which should be the perfect measuring stick, is
> showing another set of values?
> >
> > Thanks in advance. Regards.
> >
> > Julio
> >
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> reproducible code.
>