[R-sig-Geo] Convert data.frame/SpatialPointsDataFrame to raster

Thu Aug 1 10:43:52 CEST 2019

Dear Milu,

the best I can suggest is something like this.

library(raster)
df<-read.csv("path/to/data/downloaded/from/GoogleDrive")
try <- subset(df, year==2010)

sp<-SpatialPointsDataFrame(try[,1:2],data=try, proj4string =
CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"))

r<-rasterize(sp, y=raster(), field=try$TWL_5, fun=mean, background=NA)
plot(r)

Hope this helps somehow
Good luck
Hugo

Miluji Sb <milujisb using gmail.com> escreveu no dia quinta, 1/08/2019 à(s) 09:13:

> Dear Vijay,
>
> Thank you again for your reply. I tried attaching my data for two years and
> two variables but the message was rejected. I have saved the data on a
> Google Drive folder here
> <
> https://drive.google.com/drive/folders/15LvLysXqIIua8ukkp8UNEnlJMSK6mA1K?usp=sharing
> >.
> Hope this will work. Thanks again!
>
> Sincerely,
>
> Milu
>
> On Thu, Aug 1, 2019 at 9:52 AM Miluji Sb <milujisb using gmail.com> wrote:
>
> > Dear Vijay,
> >
> > Thank you again for your reply. I have attached my data for two years and
> > two variables. Hope they will go through, otherwise the files are also
> > available here
> > <
> https://drive.google.com/drive/folders/15LvLysXqIIua8ukkp8UNEnlJMSK6mA1K?usp=sharing
> >.
> > Thanks again!
> >
> > Sincerely,
> >
> > Milu
> >
> > On Wed, Jul 31, 2019 at 10:46 PM Vijay Lulla <vijaylulla using gmail.com>
> wrote:
> >
> >> Hmm...I had seen your data and thought that it was just some sample that
> >> you'd shared.  If this is your whole data then I don't know how to
> create a
> >> raster from just one row that is returned from subsetting the dataframe.
> >>
> >> Sorry for the noise.
> >>
> >> On Wed, Jul 31, 2019 at 4:16 PM Miluji Sb <milujisb using gmail.com> wrote:
> >>
> >>> Hello,
> >>>
> >>> Thank you for your kind reply.  Here is a snapshot of the original
> data.
> >>> I had pasted it at the bottom of my first email but forgot to mention
> it.
> >>> Thanks again!
> >>>
> >>> df <- structure(list(lon = c(180, 179.762810919291, 179.523658017568,
> >>> 179.311342656601, 179.067616041778, 178.851382109362, 178.648816406322,
> >>> 178.501097394651, 178.662722495847, 178.860599151485), lat =
> >>> c(-16.1529296875,
> >>> -16.21659020822, -16.266117894201, -16.393550535614, -16.4457378034442,
> >>> -16.561653799838, -16.6533087696649, -16.7741069281329,
> >>> -16.914110607613,
> >>> -16.9049389730284), nsdec = structure(c(1L, 3L, 4L, 5L, 6L, 7L,
> >>> 8L, 9L, 10L, 2L), .Label = c("1 of 10", "10 of 10", "2 of 10",
> >>> "3 of 10", "4 of 10", "5 of 10", "6 of 10", "7 of 10", "8 of 10",
> >>> "9 of 10"), class = "factor"), TWL_5 = c(2.13810426616849,
> >>> 2.16767864033646,
> >>> 2.16881240361846, 2.20727073247015, 2.27771608519709, 2.3649601141941,
> >>> 2.44210984856767, 2.52466349543977, 2.63982954290745, 2.71828906773926
> >>> ), TWL_50 = c(2.38302354555823, 2.43142793944275, 2.45733044901087,
> >>> 2.53057109758284, 2.61391337469939, 2.71040967066483, 2.82546443373866,
> >>> 2.9709907727849, 3.1785797371187, 3.33227647990861), TWL_95 =
> >>> c(2.63753852023063,
> >>> 2.7080249053612, 2.75483681166049, 2.86893038433795, 2.97758282474101,
> >>> 3.14541928966618, 3.3986143008625, 3.68043269045659, 4.09571655859075,
> >>> 4.57299670034984), year = c(2010, 2020, 2030, 2040, 2050, 2060,
> >>> 2070, 2080, 2090, 2100)), row.names = c(NA, 10L), class = "data.frame")
> >>>
> >>> Sincerely,
> >>>
> >>> Milu
> >>>
> >>> On Wed, Jul 31, 2019 at 9:20 PM Vijay Lulla <vijaylulla using gmail.com>
> >>> wrote:
> >>>
> >>>> ?`rasterFromXYZ` states that "x and y represent spatial coordinates
> and
> >>>> must be on a regular grid."  And, it appears to me that you might be
> losing
> >>>> values by rounding lon/lat values.  The help file further suggests
> that
> >>>> `rasterize` might be the function you're looking for.  List members
> will
> >>>> (certainly I will) find it more helpful to propose other solutions if
> you
> >>>> post a small reproducible example of your original georeferenced
> dataset so
> >>>> that we get an idea of what data you're using.
> >>>>
> >>>> Sorry, I cannot be of more help.
> >>>>
> >>>> On Wed, Jul 31, 2019 at 10:45 AM Miluji Sb <milujisb using gmail.com>
> wrote:
> >>>>
> >>>>> Dear all,
> >>>>>
> >>>>> I have georeferenced dataset with multiple variables and years. The
> >>>>> data is
> >>>>> at ~100 km (1° × 1°) spatial resolution. I would like to convert this
> >>>>> into
> >>>>> a raster.
> >>>>>
> >>>>> I have filtered the data for one year and one variable and did the
> >>>>> following;
> >>>>>
> >>>>> try <- subset(df, year==2010)
> >>>>> try <- try[,c(1,2,4)]
> >>>>> try$lon <- round(try$lon)
> >>>>> try$lat <- round(try$lat)
> >>>>> r_imp <- rasterFromXYZ(try)
> >>>>>
> >>>>> Two issues; is it possible to convert the original dataset with the
> >>>>> multiple variables and years to a raster? If not, how can I avoid
> >>>>> rounding
> >>>>> the coordinates? Currently, I get this error "Error in
> >>>>> rasterFromXYZ(try) :
> >>>>> x cell sizes are not regular" without rounding.
> >>>>>
> >>>>> Any help will be greatly appreciated. Thank you!
> >>>>>
> >>>>> Sincerely,
> >>>>>
> >>>>> Shouro
> >>>>>
> >>>>> ## Data
> >>>>> df <- structure(list(lon = c(180, 179.762810919291, 179.523658017568,
> >>>>> 179.311342656601, 179.067616041778, 178.851382109362,
> 178.648816406322,
> >>>>> 178.501097394651, 178.662722495847, 178.860599151485), lat =
> >>>>> c(-16.1529296875,
> >>>>> -16.21659020822, -16.266117894201, -16.393550535614,
> -16.4457378034442,
> >>>>> -16.561653799838, -16.6533087696649, -16.7741069281329,
> >>>>> -16.914110607613,
> >>>>> -16.9049389730284), nsdec = structure(c(1L, 3L, 4L, 5L, 6L, 7L,
> >>>>> 8L, 9L, 10L, 2L), .Label = c("1 of 10", "10 of 10", "2 of 10",
> >>>>> "3 of 10", "4 of 10", "5 of 10", "6 of 10", "7 of 10", "8 of 10",
> >>>>> "9 of 10"), class = "factor"), TWL_5 = c(2.13810426616849,
> >>>>> 2.16767864033646,
> >>>>> 2.16881240361846, 2.20727073247015, 2.27771608519709,
> 2.3649601141941,
> >>>>> 2.44210984856767, 2.52466349543977, 2.63982954290745,
> 2.71828906773926
> >>>>> ), TWL_50 = c(2.38302354555823, 2.43142793944275, 2.45733044901087,
> >>>>> 2.53057109758284, 2.61391337469939, 2.71040967066483,
> 2.82546443373866,
> >>>>> 2.9709907727849, 3.1785797371187, 3.33227647990861), TWL_95 =
> >>>>> c(2.63753852023063,
> >>>>> 2.7080249053612, 2.75483681166049, 2.86893038433795,
> 2.97758282474101,
> >>>>> 3.14541928966618, 3.3986143008625, 3.68043269045659,
> 4.09571655859075,
> >>>>> 4.57299670034984), year = c(2010, 2020, 2030, 2040, 2050, 2060,
> >>>>> 2070, 2080, 2090, 2100)), row.names = c(NA, 10L), class =
> "data.frame")
> >>>>>
> >>>>>         [[alternative HTML version deleted]]
> >>>>>
> >>>>> _______________________________________________
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> >>>>>
> >>>>
> >>>>
> >>>>
> >>
>
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>
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