[R] extract function extracting only NA values

[Fabio Berzaghi]

ok so i imported the raster as a dataframe and everything is fine
    Min.   :-69826220
    Max.   :167780500

so it's something with values lower than -9999 that are interpreted as 
NA by the raster function


On 4/24/2013 13:52, Fabio Berzaghi wrote:
> So I think I might have found what is causing this problem. The values 
> I have in this raster
>
> > summary(ps0011yme)
>                 layer
> Min.        -9458.911
> 1st Qu.   1955256.000
> Median   10618870.000
> 3rd Qu.  79577730.000
> Max.    167780500.000
> NA's            0.000
>
> From ArcMap though I get different values
> min -69826224 and max 167780496
>
> So maybe when I am importing the rest are in R something goes wrong 
> and all the values below a certain threshold are considered NA. Is 
> this a bug or do I get to use a specific parameter for the raster 
> function?
>
>
> On 4/24/2013 13:10, Fabio Berzaghi wrote:
>> Hello,
>>
>> I have five raster files in ASCII format. With four of them I have no 
>> problem extracting values based on a set of X and Y coordinates. 
>> Unfortunately with one of the files all I managed to extract is NA 
>> values. To verify the problem I have opened the raster with ArcMap 
>> and there are no NA values where I am extracting. I have also plotted 
>> the spatial point class on top of the raster in R and it does 
>> correspond to the correct locations.
>>
>> These are some of the commands I am using, and as I already pointed 
>> out that works perfectly with other raster files.
>>
>> sp<-SpatialPoints(xysp)
>> xy$rasterimg<-extract(rasterimg,sp)
>>
>> Can anyone help? At this point I am rather clueless about this.
>>
>> Thanks
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide 
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.