On 04/08/2016 08:50 AM, Frede Aakmann Tøgersen wrote:
Reposting again again without data. So fetch the data yourself :-(
Yours sincerely / Med venlig hilsen
Frede Aakmann Tøgersen
Specialist, M.Sc., Ph.D.
Plant Performance & Modeling
Technology & Service Solutions
T +45 9730 5135
M +45 2547 6050
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-----Original Message-----
From: Frede Aakmann Tøgersen
Sent: 8. april 2016 08:46
To: Maggie CY Lau (mag...@princeton.edu)
Cc: r-sig-geo@r-project.org
Subject: FW: proj4string error on data.frame generated from NCEP data
Reposting without attachments.
Yours sincerely / Med venlig hilsen
Frede Aakmann Tøgersen
Specialist, M.Sc., Ph.D.
Plant Performance & Modeling
Technology & Service Solutions
T +45 9730 5135
M +45 2547 6050
fr...@vestas.com
http://www.vestas.com
Company reg. name: Vestas Wind Systems A/S
This e-mail is subject to our e-mail disclaimer statement.
Please refer to www.vestas.com/legal/notice
If you have received this e-mail in error please contact the sender.
-----Original Message-----
From: Frede Aakmann Tøgersen
Sent: 8. april 2016 08:01
To: 'Maggie CY Lau'; r-sig-geo@r-project.org
Subject: RE: proj4string error on data.frame generated from NCEP data
Hi Maggie
Your error message says that there is some coordinates with latitudes above 90
degrees.
The problem seems to arise from the call to gridded. See below for a dput'ed version of the
dataframe "air.sig995.ag.df" called "friend" in my code. This is what I found
out:
coordinates(friend) <- ~longitude+latitude
bbox(friend)
min max
longitude -177.5 180
latitude 60.0 90
apply(coordinates(friend), 2, range)
longitude latitude
[1,] -177.5 60
[2,] 180.0 90
After using gridded() the bounding box is enlarged somewhat but the coordinates
still unchanged.
gridded(friend) <- TRUE
bbox(friend)
min max
longitude -178.75 181.25
latitude 58.75 91.25
apply(coordinates(friend), 2, range)
longitude latitude
[1,] -177.5 60
[2,] 180.0 90
If you leave out the gridded() part I guess you can proceed towards your goal.
Here I did:
## this was okay
crs <- "+proj=longlat +datum=WGS84"
proj4string(friend) <- crs
## see attached plot
png("longlat.png")
plot(friend)
dev.off()
Do a reprojection with spTransform():
stere <- "+proj=stere +lat_0=90 +lat_ts=60 +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84
+datum=WGS84 +units=m +no_defs"
friend.stere <- spTransform(friend, CRS(stere))
And the plot is attached:
png("stere.png")
plot(friend.stere)
dev.off()
X11cairo
Why gridded() is extending domain outside permissible values for longitude and
latitude I don't know.
My guess is that gridded assumes coordinates provided correspond to
pixels centers, while top-left coordinates are provided.
Cheers,
Loïc
\Frede
##### friend is a copy of air.sig995.ag.df <- NCEP.array2df(air.sig995.ag[,,1],
var.names = 'Temperature')
## DELETED
Yours sincerely / Med venlig hilsen
Frede Aakmann Tøgersen
Specialist, M.Sc., Ph.D.
Plant Performance & Modeling
Technology & Service Solutions
T +45 9730 5135
M +45 2547 6050
fr...@vestas.com
http://www.vestas.com
Company reg. name: Vestas Wind Systems A/S
This e-mail is subject to our e-mail disclaimer statement.
Please refer to www.vestas.com/legal/notice
If you have received this e-mail in error please contact the sender.
-----Original Message-----
From: R-sig-Geo [mailto:r-sig-geo-boun...@r-project.org] On Behalf Of Maggie CY
Lau
Sent: 7. april 2016 16:24
To: r-sig-geo@r-project.org
Subject: [R-sig-Geo] proj4string error on data.frame generated from NCEP data
HI all,
I am an ecologist who would like to use several datasets generated by NCEP reanalysis. I attempted
to use the R package "RNCEP" to extract the data and generate .tiff files. These files
will be analyzed by a student using ArcMap. I created the data fame with the information I need,
but had problem exporting the data into .tiff file that can be projected in polar stereograph in
ArcMap. The use of "+proj=longlat + datum=WGS84" gave the following error message:
Error in `proj4string<-`(`*tmp*`, value = <S4 object of class "CRS">) :
Geographical CRS given to non-conformant data: 91.25
Then I tried using ""+proj=stere +lat_0=90 +lat_ts=60 +lon_0=0 +k=1 +x_0=0 +y_0=0
+ellps=WGS84 +datum=WGS84 +units=m +no_defs". proj4string went fine but the export tiff
appeared as a box image instead of an angular one.
Please kindly check the following codes from the line "library(sp)" onward.
Thanks,
Maggie Lau
====
install.packages("RNCEP", dependencies=TRUE)
install.packages(c('abind', 'maps', 'fields', 'tgp', 'fossil'),
dependencies=TRUE)
install.packages("raster")
install.packages("rgdal")
library(RNCEP)
air.sig995.extent <- NCEP.gather(variable='air.sig995', level='surface',
months.minmax=c(7),
years.minmax=c(2011), lat.southnorth=c(60,89.9), lon.westeast=c(-179,180),
reanalysis2=FALSE, return.units=TRUE)
air.sig995.ag <- NCEP.aggregate(wx.data=air.sig995.extent, YEARS=TRUE,
MONTHS=TRUE,
DAYS=FALSE, HOURS=FALSE, fxn='mean')
dimnames(air.sig995.ag)[[3]][1]
air.sig995.ag.df <- NCEP.array2df(air.sig995.ag[,,1], var.names = 'Temperature')
library(sp)
coordinates(air.sig995.ag.df) <- ~longitude+latitude
gridded(air.sig995.ag.df) <- TRUE
crs <- "+proj=longlat + datum=WGS84"
proj4string(air.sig995.ag.df) <- CRS(crs)
#stere <- "+proj=stere +lat_0=90 +lat_ts=60 +lon_0=0
# +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs"
#proj4string(air.sig995.ag.df) <- CRS(stere)
library(raster)
ras <- raster(air.sig995.ag.df)
writeRaster(ras, 'air.sig995.Jul.ag.tif', overwrite=TRUE)
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