[R-sig-Geo] Help

[Roger Bivand]

On Thu, 9 Jan 2020, Ben Tupper wrote:

> Your assignments that look like...
>
> minx <-  rain_data_UTM at bbox[1,1]
>
> are not valid R statements - and that will cause an error.

I think that this might be the mail or some other system replacing 
commercial at by at. Better syntax might be:

minx <-  slot(rain_data_UTM, "bbox")[1,1]

if this was the real intention, as slot() is the preferred script-level S4 
slot accessor, although one finds lots of untidy examples using 
commercial at in blogs and elsewhere on the net. However, your version is 
obviously much easier to read:

> Instead,
> obtain a matrix of the bounding box using the bbox() function.  Then
> extract your coordinates from that. I think you want...
>
> bb <- bbox(rain_data_UTM)
> minx <- bb[1,1]
> maxx <- bb[1,2]
> miny <- bb[2,1]
> maxy <- bb[2,2]

And yes, this is very good advice!

Roger

>
> If you haven't seen this, https://www.rspatial.org/ , it is well worth your
> time.  There are a lot of other great resources about using spatial data in
> R.  Try searching the Rseek.org. Like this
> https://rseek.org/?q=spatial+tutorials  It is a gold mine.
>
>
> On Thu, Jan 9, 2020 at 1:42 PM Bakary Faty <bakaryfaty using gmail.com> wrote:
>
>> Thank you for appreciated reply,
>>
>> I explane you exactly what I want to do with this R code attached.
>> I want to adapt this code to my data to build an isohyet map.
>> But i have some difficulties to adapt it to my case.
>> I will be very happy when you will help my to adapt this R code (attached)
>> to my case.
>> You can find attached the you R code, my data file and my sahefile of
>> watershed.
>>
>> Best regards
>>
>>
>> Le jeu. 9 janv. 2020 à 17:47, Ben Tupper <btupper using bigelow.org> a écrit :
>>
>>> Welcome to r-sig-geo!
>>>
>>> I don't think that you haven't provided us enough information so that we
>>> can help.  On the other hand, does the example below using expand.grid help?
>>>
>>> minx <- 20
>>> maxx <- 25
>>> miny <- 31
>>> maxy <- 36
>>> pixel <- 1
>>> grd <- expand.grid(x = seq(minx, maxx, by=pixel), y = seq(miny, maxy,
>>> by=pixel))
>>>
>>> Ben
>>>
>>> On Thu, Jan 9, 2020 at 11:41 AM Bakary Faty <bakaryfaty using gmail.com> wrote:
>>>
>>>>
>>>> Dear,
>>>>
>>>> I'm writing to express my wish to join R-sig-geo list users.
>>>> I was doing a search on the net to know how to build an isohyet map and
>>>> I came across this R code.
>>>> However, I stumbled upon a problem from the line :
>>>> grd <- expand.grid(x=seq(minx, maxx, by=pixel), y=seq(miny, maxy,
>>>> by=pixel)),
>>>> I get the following error message:
>>>> default method not implemented for type 'S4'. I want to know how resolve
>>>> this error.
>>>>
>>>> Also, I would like to ask you only at the line level:
>>>> minx <- rain_data_UTM at bbox[1,1]
>>>> maxx <- rain_data_UTM at bbox[1,2]
>>>> miny <- rain_data_UTM at bbox[2,1]
>>>> maxy <- rain_data_UTM at bbox[2,2],
>>>> if I should limit myself to "rain_data_UTM" or write completely:
>>>> rain_data_UTM at bbox[,].
>>>>  By the way, this is the pointfile I reconstructed.
>>>> You can find it attached to the mail.
>>>>
>>>> Thanks in advance
>>>>
>>>> Best regards
>>>>
>>>>
>>>>
>>>> Bakary
>>>> _______________________________________________
>>>> R-sig-Geo mailing list
>>>> R-sig-Geo using r-project.org
>>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>>
>>>
>>>
>>> --
>>> Ben Tupper
>>> Bigelow Laboratory for Ocean Science
>>> West Boothbay Harbor, Maine
>>> http://www.bigelow.org/
>>> https://eco.bigelow.org
>>>
>>>
>>
>> --
>>
>>
>>
>> Bakary
>>
>
>
>

-- 
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: Roger.Bivand using nhh.no
https://orcid.org/0000-0003-2392-6140
https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en