Sarah's answer is probably better depending on what you want to do with the resulting data, but here's a way to go from your original DF1 to DF2:> DF1 <- structure(list(latitude = c(45.5, 45.5, 45.5, 45.5, 46, 46, 46,+ 46), longitude = c(110.5, 111, 111.5, 112, 110.5, 111, 111.5, + 112), Precip = c(3.2, 5, 1.8, 2, 6.1, 4.5, 7.8, 5.5)), + class = "data.frame", row.names = c(NA, -8L))># Convert to table with xtabs()> DF2 <- xtabs(Precip~latitude+longitude, DF1) ># Reverse the order of the latitudes> DF2 <- DF2[rev(rownames(DF2)), ] > DF2longitude latitude 110.5 111 111.5 112 46 6.1 4.5 7.8 5.5 45.5 3.2 5.0 1.8 2.0 # Convert to a data frame> DF2 <- as.data.frame.matrix(DF2) > DF2110.5 111 111.5 112 46 6.1 4.5 7.8 5.5 45.5 3.2 5.0 1.8 2.0 ---------------------------------------- David L Carlson Department of Anthropology Texas A&M University College Station, TX 77843-4352 -----Original Message----- From: R-help <r-help-bounces at r-project.org> On Behalf Of Sarah Goslee Sent: Tuesday, November 13, 2018 8:16 AM To: lily li <chocold12 at gmail.com> Cc: r-help <r-help at r-project.org> Subject: Re: [R] How to create gridded data If you want an actual spatial dataset, the best place to ask is R-sig-geo R has substantial capabilities for dealing with gridded spatial data, including in the sp, raster, and sf packages. Here's one approach, creating a SpatialGridDataFrame, which can be exported in any standard raster format using the rgdal package. DF2 <- DF1 coordinates(DF2) <- ~longitude + latitude gridded(DF2) <- TRUE fullgrid(DF2) <- TRUE I recommend Roger Bivand's excellent book: https://www.springer.com/us/book/9781461476177 and there are abundant web tutorials. Sarah On Tue, Nov 13, 2018 at 2:22 AM lily li <chocold12 at gmail.com> wrote:> > Hi R users, > > I have a question about manipulating data. For example, I have DF1 as the > following, how to transform it to a gridded dataset DF2? In DF2, each value > Precip is an attribute of the corresponding grid cell. So DF2 is like a > spatial surface, and can be imported to ArcGIS. Thanks for your help. > > DF1 > latitude longitude Precip > 45.5 110.5 3.2 > 45.5 111 5.0 > 45.5 111.5 1.8 > 45.5 112 2.0 > 46 110.5 6.1 > 46 111 4.5 > 46 111.5 7.8 > 46 112 5.5 > ... > > > DF2 > 6.1 4.5 7.8 5.5 > 3.2 5.0 1.8 2.0 > ... >-- Sarah Goslee (she/her) http://www.numberwright.com ______________________________________________ R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
Thanks, Sarah's answer helps the question. Now how to change the gridded data back to DF1 format? I don't know how to name the format, thanks. On Tue, Nov 13, 2018 at 10:56 PM David L Carlson <dcarlson at tamu.edu> wrote:> Sarah's answer is probably better depending on what you want to do with > the resulting data, but here's a way to go from your original DF1 to DF2: > > > DF1 <- structure(list(latitude = c(45.5, 45.5, 45.5, 45.5, 46, 46, 46, > + 46), longitude = c(110.5, 111, 111.5, 112, 110.5, 111, 111.5, > + 112), Precip = c(3.2, 5, 1.8, 2, 6.1, 4.5, 7.8, 5.5)), > + class = "data.frame", row.names = c(NA, -8L)) > > > # Convert to table with xtabs() > > DF2 <- xtabs(Precip~latitude+longitude, DF1) > > > > # Reverse the order of the latitudes > > DF2 <- DF2[rev(rownames(DF2)), ] > > DF2 > longitude > latitude 110.5 111 111.5 112 > 46 6.1 4.5 7.8 5.5 > 45.5 3.2 5.0 1.8 2.0 > > # Convert to a data frame > > DF2 <- as.data.frame.matrix(DF2) > > DF2 > 110.5 111 111.5 112 > 46 6.1 4.5 7.8 5.5 > 45.5 3.2 5.0 1.8 2.0 > > ---------------------------------------- > David L Carlson > Department of Anthropology > Texas A&M University > College Station, TX 77843-4352 > > > -----Original Message----- > From: R-help <r-help-bounces at r-project.org> On Behalf Of Sarah Goslee > Sent: Tuesday, November 13, 2018 8:16 AM > To: lily li <chocold12 at gmail.com> > Cc: r-help <r-help at r-project.org> > Subject: Re: [R] How to create gridded data > > If you want an actual spatial dataset, the best place to ask is R-sig-geo > > R has substantial capabilities for dealing with gridded spatial data, > including in the sp, raster, and sf packages. > > Here's one approach, creating a SpatialGridDataFrame, which can be > exported in any standard raster format using the rgdal package. > > DF2 <- DF1 > coordinates(DF2) <- ~longitude + latitude > gridded(DF2) <- TRUE > fullgrid(DF2) <- TRUE > > I recommend Roger Bivand's excellent book: > https://www.springer.com/us/book/9781461476177 > > and there are abundant web tutorials. > > Sarah > On Tue, Nov 13, 2018 at 2:22 AM lily li <chocold12 at gmail.com> wrote: > > > > Hi R users, > > > > I have a question about manipulating data. For example, I have DF1 as the > > following, how to transform it to a gridded dataset DF2? In DF2, each > value > > Precip is an attribute of the corresponding grid cell. So DF2 is like a > > spatial surface, and can be imported to ArcGIS. Thanks for your help. > > > > DF1 > > latitude longitude Precip > > 45.5 110.5 3.2 > > 45.5 111 5.0 > > 45.5 111.5 1.8 > > 45.5 112 2.0 > > 46 110.5 6.1 > > 46 111 4.5 > > 46 111.5 7.8 > > 46 112 5.5 > > ... > > > > > > DF2 > > 6.1 4.5 7.8 5.5 > > 3.2 5.0 1.8 2.0 > > ... > > > > > -- > Sarah Goslee (she/her) > http://www.numberwright.com > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. >[[alternative HTML version deleted]]
Sarah's answer is probably the best approach, but to do it using very basic
R methods that predate the very good spatial support that R now has, I would
likely do this:
## Thanks, Jim Lemon, for this step:
df1 <- read.table(text"latitude longitude Precip
45.5 110.5 3.2
45.5 111 5.0
45.5 111.5 1.8
45.5 112 2.0
46 110.5 6.1
46 111 4.5
46 111.5 7.8
46 112 5.5",
header=TRUE)
## first sort
df1 <- df1[order(df1$latitude, df1$longitude) , ]
## convert vector of precipitations to matrix
df2 <- matrix(df1$Precip, nrow=length(unique(df1$latitude)), byrow=TRUE)
## reorder the latitudes (rows)
df2 <- df2[ nrow(df2):1 , ]
## > df2
## [,1] [,2] [,3] [,4]
## [1,] 6.1 4.5 7.8 5.5
## [2,] 3.2 5.0 1.8 2.0
## From the original question:
## DF2
## 6.1 4.5 7.8 5.5
## 3.2 5.0 1.8 2.0
## ...
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
Lab cell 925-724-7509
?On 11/13/18, 8:50 PM, "R-help on behalf of lily li"
<r-help-bounces at r-project.org on behalf of chocold12 at gmail.com>
wrote:
Thanks, Sarah's answer helps the question. Now how to change the gridded
data back to DF1 format? I don't know how to name the format, thanks.
On Tue, Nov 13, 2018 at 10:56 PM David L Carlson <dcarlson at
tamu.edu> wrote:
> Sarah's answer is probably better depending on what you want to do
with
> the resulting data, but here's a way to go from your original DF1
to DF2:
>
> > DF1 <- structure(list(latitude = c(45.5, 45.5, 45.5, 45.5, 46,
46, 46,
> + 46), longitude = c(110.5, 111, 111.5, 112, 110.5, 111, 111.5,
> + 112), Precip = c(3.2, 5, 1.8, 2, 6.1, 4.5, 7.8, 5.5)),
> + class = "data.frame", row.names = c(NA, -8L))
> >
> # Convert to table with xtabs()
> > DF2 <- xtabs(Precip~latitude+longitude, DF1)
> >
>
> # Reverse the order of the latitudes
> > DF2 <- DF2[rev(rownames(DF2)), ]
> > DF2
> longitude
> latitude 110.5 111 111.5 112
> 46 6.1 4.5 7.8 5.5
> 45.5 3.2 5.0 1.8 2.0
>
> # Convert to a data frame
> > DF2 <- as.data.frame.matrix(DF2)
> > DF2
> 110.5 111 111.5 112
> 46 6.1 4.5 7.8 5.5
> 45.5 3.2 5.0 1.8 2.0
>
> ----------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77843-4352
>
>
> -----Original Message-----
> From: R-help <r-help-bounces at r-project.org> On Behalf Of Sarah
Goslee
> Sent: Tuesday, November 13, 2018 8:16 AM
> To: lily li <chocold12 at gmail.com>
> Cc: r-help <r-help at r-project.org>
> Subject: Re: [R] How to create gridded data
>
> If you want an actual spatial dataset, the best place to ask is
R-sig-geo
>
> R has substantial capabilities for dealing with gridded spatial data,
> including in the sp, raster, and sf packages.
>
> Here's one approach, creating a SpatialGridDataFrame, which can be
> exported in any standard raster format using the rgdal package.
>
> DF2 <- DF1
> coordinates(DF2) <- ~longitude + latitude
> gridded(DF2) <- TRUE
> fullgrid(DF2) <- TRUE
>
> I recommend Roger Bivand's excellent book:
> https://www.springer.com/us/book/9781461476177
>
> and there are abundant web tutorials.
>
> Sarah
> On Tue, Nov 13, 2018 at 2:22 AM lily li <chocold12 at gmail.com>
wrote:
> >
> > Hi R users,
> >
> > I have a question about manipulating data. For example, I have DF1
as the
> > following, how to transform it to a gridded dataset DF2? In DF2,
each
> value
> > Precip is an attribute of the corresponding grid cell. So DF2 is
like a
> > spatial surface, and can be imported to ArcGIS. Thanks for your
help.
> >
> > DF1
> > latitude longitude Precip
> > 45.5 110.5 3.2
> > 45.5 111 5.0
> > 45.5 111.5 1.8
> > 45.5 112 2.0
> > 46 110.5 6.1
> > 46 111 4.5
> > 46 111.5 7.8
> > 46 112 5.5
> > ...
> >
> >
> > DF2
> > 6.1 4.5 7.8 5.5
> > 3.2 5.0 1.8 2.0
> > ...
> >
>
>
> --
> Sarah Goslee (she/her)
> http://www.numberwright.com
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>
[[alternative HTML version deleted]]
______________________________________________
R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
It would depend on the format of the gridded data. Assuming it is a data frame like DF2 in my earlier answer, you just reverse the steps:> DF2110.5 111 111.5 112 46 6.1 4.5 7.8 5.5 45.5 3.2 5.0 1.8 2.0> DF3 <- data.frame(as.table(as.matrix(DF2)))Var1 Var2 Freq 1 46 110.5 6.1 2 45.5 110.5 3.2 3 46 111 4.5 4 45.5 111 5.0 5 46 111.5 7.8 6 45.5 111.5 1.8 7 46 112 5.5 8 45.5 112 2.0 But the latitude and longitude get converted to factors and we lose the column names:> DF3 <- data.frame(as.table(as.matrix(DF2))) > colnames(DF3) <- c("latitude", "longitude", "Precip") > DF3$latitude <- as.numeric(as.character(DF3$latitude)) > DF3$longitude <- as.numeric(as.character(DF3$longitude))---------------------------------------- David L Carlson Department of Anthropology Texas A&M University College Station, TX 77843-4352 From: lily li <chocold12 at gmail.com> Sent: Tuesday, November 13, 2018 10:50 PM To: David L Carlson <dcarlson at tamu.edu> Cc: Sarah Goslee <sarah.goslee at gmail.com>; R mailing list <r-help at r-project.org> Subject: Re: [R] How to create gridded data Thanks, Sarah's answer helps the question. Now how to change the gridded data back to DF1 format? I don't know how to name the format, thanks. On Tue, Nov 13, 2018 at 10:56 PM David L Carlson <mailto:dcarlson at tamu.edu> wrote: Sarah's answer is probably better depending on what you want to do with the resulting data, but here's a way to go from your original DF1 to DF2:> DF1 <- structure(list(latitude = c(45.5, 45.5, 45.5, 45.5, 46, 46, 46,+? ? ? ? ?46), longitude = c(110.5, 111, 111.5, 112, 110.5, 111, 111.5, +? ? ? ? ?112), Precip = c(3.2, 5, 1.8, 2, 6.1, 4.5, 7.8, 5.5)), +? ? ? ? ?class = "data.frame", row.names = c(NA, -8L))># Convert to table with xtabs()> DF2 <- xtabs(Precip~latitude+longitude, DF1) ># Reverse the order of the latitudes> DF2 <- DF2[rev(rownames(DF2)), ] > DF2? ? ? ? longitude latitude 110.5 111 111.5 112 ? ? 46? ? ?6.1 4.5? ?7.8 5.5 ? ? 45.5? ?3.2 5.0? ?1.8 2.0 # Convert to a data frame> DF2 <- as.data.frame.matrix(DF2) > DF2? ? ?110.5 111 111.5 112 46? ? ?6.1 4.5? ?7.8 5.5 45.5? ?3.2 5.0? ?1.8 2.0 ---------------------------------------- David L Carlson Department of Anthropology Texas A&M University College Station, TX 77843-4352 -----Original Message----- From: R-help <mailto:r-help-bounces at r-project.org> On Behalf Of Sarah Goslee Sent: Tuesday, November 13, 2018 8:16 AM To: lily li <mailto:chocold12 at gmail.com> Cc: r-help <mailto:r-help at r-project.org> Subject: Re: [R] How to create gridded data If you want an actual spatial dataset, the best place to ask is R-sig-geo R has substantial capabilities for dealing with gridded spatial data, including in the sp, raster, and sf packages. Here's one approach, creating a SpatialGridDataFrame, which can be exported in any standard raster format using the rgdal package. DF2 <- DF1 coordinates(DF2) <- ~longitude + latitude gridded(DF2) <- TRUE fullgrid(DF2) <- TRUE I recommend Roger Bivand's excellent book: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.springer.com_us_book_9781461476177&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=veMGHMCNZShld-KX-bIj4jRE_tP9ojUvB_Lqp0ieSdk&m=vZqNKoDe8N1TzBzeK12g2oa0cBS8VD6NDCs-hUhvt5o&s=B73PwZQrdKUmM1ML2Y5zjaEz7xqkHlzBDCrhluogK2U&e and there are abundant web tutorials. Sarah On Tue, Nov 13, 2018 at 2:22 AM lily li <mailto:chocold12 at gmail.com> wrote:> > Hi R users, > > I have a question about manipulating data. For example, I have DF1 as the > following, how to transform it to a gridded dataset DF2? In DF2, each value > Precip is an attribute of the corresponding grid cell. So DF2 is like a > spatial surface, and can be imported to ArcGIS. Thanks for your help. > > DF1 > latitude? ?longitude? ?Precip > 45.5? ? ? ? ? ?110.5? ? ? ? ?3.2 > 45.5? ? ? ? ? ?111? ? ? ? ? ? 5.0 > 45.5? ? ? ? ? ?111.5? ? ? ? ?1.8 > 45.5? ? ? ? ? ?112? ? ? ? ? ? 2.0 > 46? ? ? ? ? ? ? 110.5? ? ? ? ?6.1 > 46? ? ? ? ? ? ? 111? ? ? ? ? ? 4.5 > 46? ? ? ? ? ? ? 111.5? ? ? ? ?7.8 > 46? ? ? ? ? ? ? 112? ? ? ? ? ? 5.5 > ... > > > DF2 > 6.1? ?4.5? ?7.8? ?5.5 > 3.2? ?5.0? ?1.8? ?2.0 > ... >-- Sarah Goslee (she/her) https://urldefense.proofpoint.com/v2/url?u=http-3A__www.numberwright.com&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=veMGHMCNZShld-KX-bIj4jRE_tP9ojUvB_Lqp0ieSdk&m=vZqNKoDe8N1TzBzeK12g2oa0cBS8VD6NDCs-hUhvt5o&s=qSosThG59aeSFYzVFf1e-YQGbuBKVbvgVi1z9nFm884&e ______________________________________________ mailto:R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Dhelp&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=veMGHMCNZShld-KX-bIj4jRE_tP9ojUvB_Lqp0ieSdk&m=vZqNKoDe8N1TzBzeK12g2oa0cBS8VD6NDCs-hUhvt5o&s=2pS9yFu5bpcRyCi1vX_OEDD2Ie8ZihvOQrkDQSNu8RM&ePLEASE do read the posting guide https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.org_posting-2Dguide.html&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=veMGHMCNZShld-KX-bIj4jRE_tP9ojUvB_Lqp0ieSdk&m=vZqNKoDe8N1TzBzeK12g2oa0cBS8VD6NDCs-hUhvt5o&s=1brzEOjZ4EUr_llqwyO274DfJfsOpRBI-pmd-hp0WAQ&eand provide commented, minimal, self-contained, reproducible code.