[R-sig-Geo] Implementing a rolling window for stars object

[Andy Teucher]

I’m fairly certain this is a bug in stars; I opened an issue here: https://github.com/r-spatial/stars/issues/223 <https://github.com/r-spatial/stars/issues/223>

Cheers,
Andy Teucher

> On Oct 23, 2019, at 10:42 AM, Andy Teucher <andy.teucher using gmail.com> wrote:
> 
> Interesting - there’s some rlang/tidy evaluation trickery going on there that I couldn’t quite figure out (I think it might be searching for yr in the wrong environment), but defining your range as a single variable, and putting that in the square brackets seems to work for me:
> 
> rng <- yr:last_yr
> stars_window = ci_stars[,,,rng]
> 
> 
>> On Oct 23, 2019, at 10:20 AM, Micha Silver <tsvibar using gmail.com> wrote:
>> 
>> 
>> On 23/10/2019 19:30, Andy Teucher wrote:
>>> Hi Micha,
>>> 
>>> I can see two problems immediately with your code:
>>> 1. you are using a double-colon (yr::last_yr) - the double colon is used for looking for an object in a package, so it is looking for object ‘yrs’ in package ‘yr’, which obviously doesn’t make sense. Use a single colon to create a range (like you did with 2:6)
>>> 2.  the object ‘last_yr’ is never defined, so even if you used a single colon to define the range yr:last_yr, it would fail as it would not be able to find object ‘last_yr’
>>> 
>> 
>> Thanks,
>> 
>> I fixed those typos (corrected script attached) and I still get this error:
>> 
>> 
>> micha using tp480:R$ Rscript stars_window.R
>> Loading required package: abind
>> Loading required package: sf
>> Linking to GEOS 3.7.1, GDAL 2.4.0, PROJ 5.2.0
>> Error in eval(rlang::expr(x[[i]][!!!args])) : object 'yr' not found
>> Calls: RunMK -> [ -> [.stars -> structure -> eval -> eval
>> Execution halted
>> 
>> 
>> 
>>> Cheers,
>>> Andy Teucher
>>> 
>>>> On Oct 23, 2019, at 8:28 AM, Micha Silver <tsvibar using gmail.com <mailto:tsvibar using gmail.com>> wrote:
>>>> 
>>>> I am trying to run a function (mk.test to find MannKendall trends) using st_apply over a "rolling" window for a time series of rasters in a stars object.
>>>> When I use subscript notation to slice out the window dimension with a looping variable I get an error:
>>>> 
>>>> Error in loadNamespace(name) : there is no package called ‘yr’
>>>> Calls: [ ... tryCatch -> tryCatchList -> tryCatchOne -> <Anonymous>
>>>> Execution halted
>>>> 
>>>> However If I replace the subscript with integers it works fine. (see attached)
>>>> What is the correct way to work this out?
>>>> 
>>>> Attached is a reprex with a small subset of my data. (The script starts with a long structure, code is at the end)
>>>> 
>>>> Thanks
>>>> --
>>>> Micha Silver
>>>> Ben Gurion Univ.
>>>> Sde Boker, Remote Sensing Lab
>>>> cell: +972-523-665918
>>>> <stars_window.R>_______________________________________________
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>>> 
>> -- 
>> Micha Silver
>> Ben Gurion Univ.
>> Sde Boker, Remote Sensing Lab
>> cell: +972-523-665918
>> 
>> <stars_window.R>
> 


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