[R] allequal diff

[sibyiie@stoeckii m@iii@g oii gmx@ch]

Dear Ben

 

Many thanks.

I see that a second challenge are NA values. Is it possible to consider na.rm=TRUE?

 

> r2_resampled <- resample(r2, r1)

> compareRaster(r1, r2_resampled)

[1] TRUE

> 

> all.equal(getValues(r1), getValues(r2_resampled), tolerance = 0)

[1] "'is.NA' value mismatch: 9544032 in current 66532795 in target"

 

Kind regards

Sibylle 

 

 

-----Original Message-----
From: R-help <r-help-bounces using r-project.org> On Behalf Of Ben Bolker
Sent: Friday, August 16, 2024 1:06 AM
To: r-help using r-project.org
Subject: Re: [R] allequal diff

 

 

   Digging into the code for raster::compareRaster():

 

library(raster)

r <- raster(ncol=3, nrow=3)

values(r) <- 1:ncell(r)

r2 <- r

values(r2) <- c(1:8,10)

all.equal(getValues(r), getValues(r2), tolerance = 0) [1] "Mean relative difference: 0.1111111"

 

    compareRaster has fancier machinery internally for doing the comparison for large rasters a block at a time if everything can't fit in memory at the same time ...

 

 

 

 

On 2024-08-15 9:14 a.m., SIBYLLE STÖCKLI via R-help wrote:

> Dear community

> 

> 

> 

> Similar to the example of the rdocumentation, my idea is to use 

> all.equal and to print the difference.

> 

>  <https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/all> https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/all

> .equal

> 

> 

> 

>> d45 <- pi*(1/4 + 1:10)

> 

>> stopifnot(

> 

> +     all.equal(tan(d45), rep(1, 10)))          # TRUE, but

> 

>> all      (tan(d45) == rep(1, 10))         # FALSE, since not exactly

> 

> [1] FALSE

> 

>> all.equal(tan(d45), rep(1, 10), tolerance = 0)  # to see difference

> 

> [1] "Mean relative difference: 1.29526e-15"

> 

>> 

> 

> 

> 

> Unfortunately, I just get "FALSE" not the difference.

> 

>> r2_resampled <- resample(r2, r1)

> 

>> compareRaster(r1, r2_resampled)

> 

> [1] TRUE

> 

>> # Compare rasters

> 

>> result <- all.equal(r1, r2_resampled)

> 

> Warning message:

> 

> In compareRaster(target, current, ..., values = values, stopiffalse = 

> stopiffalse,  :

> 

>    not all objects have the same values

> 

>> print(result)

> 

> [1] FALSE

> 

>> 

> 

> 

> 

> Kind regards

> 

> Sibylle

> 

> 

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> 

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--

Dr. Benjamin Bolker

Professor, Mathematics & Statistics and Biology, McMaster University Director, School of Computational Science and Engineering  > E-mail is sent at my convenience; I don't expect replies outside of working hours.

 

______________________________________________

 <mailto:R-help using r-project.org> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see  <https://stat.ethz.ch/mailman/listinfo/r-help> https://stat.ethz.ch/mailman/listinfo/r-help

PLEASE do read the posting guide  <http://www.R-project.org/posting-guide.html> http://www.R-project.org/posting-guide.html

and provide commented, minimal, self-contained, reproducible code.


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