Well no need to have your data. Usually one can find some suitable data in the
help for the functions under question. So here is a reproducible example from
?meuse.grid.
> data(meuse.grid)
> coordinates(meuse.grid) <- ~x+y
> proj4string(meuse.grid) <- CRS("+init=epsg:28992") # see ?meuse for this crs
> gridded(meuse.grid) <- TRUE
> summary(meuse.grid)
Object of class SpatialPixelsDataFrame
Coordinates:
min max
x 178440 181560
y 329600 333760
Is projected: TRUE
proj4string :
[+init=epsg:28992 +proj=sterea +lat_0=52.15616055555555
+lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000
+ellps=bessel +units=m +no_defs]
Number of points: 3103
Grid attributes:
cellcentre.offset cellsize cells.dim
x 178460 40 78
y 329620 40 104
Data attributes:
part.a part.b dist soil ffreq
Min. :0.0000 Min. :0.0000 Min. :0.0000 1:1665 1: 779
1st Qu.:0.0000 1st Qu.:0.0000 1st Qu.:0.1193 2:1084 2:1335
Median :0.0000 Median :1.0000 Median :0.2715 3: 354 3: 989
Mean :0.3986 Mean :0.6014 Mean :0.2971
3rd Qu.:1.0000 3rd Qu.:1.0000 3rd Qu.:0.4402
Max. :1.0000 Max. :1.0000 Max. :0.9926
> rasterMG <- raster(meuse.grid)
> print(rasterMG)
class : RasterLayer
dimensions : 104, 78, 8112 (nrow, ncol, ncell)
resolution : 40, 40 (x, y)
extent : 178440, 181560, 329600, 333760 (xmin, xmax, ymin, ymax)
coord. ref. : +init=epsg:28992 +proj=sterea +lat_0=52.15616055555555
+lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel
+units=m +no_defs
data source : in memory
names : part.a
values : 0, 1 (min, max)
> rasterMG.proj <- spTransform(rasterMG, CRS("+init=epsg:21781"))
Error in spTransform(rasterMG, CRS("+init=epsg:21781")) :
load package rgdal for spTransform methods
>
Now perhaps doing the projection before casting it to a raster will work (yes
I'm guessing since error thrown above is not very informative and traceback()
does not give anything useful).
> meuse.grid.proj <- spTransform(meuse.grid, CRS("+init=epsg:21781"))
Warning message:
In spTransform(meuse.grid, CRS("+init=epsg:21781")) :
Grid warping not available, coercing to points
> summary(meuse.grid.proj)
Object of class SpatialPointsDataFrame
Coordinates:
min max
x 479029.8 482197.1
y 646927.4 651003.9
Is projected: TRUE
proj4string :
[+init=epsg:21781 +proj=somerc +lat_0=46.95240555555556
+lon_0=7.439583333333333 +k_0=1 +x_0=600000 +y_0=200000 +ellps=bessel
+towgs84=674.374,15.056,405.346,0,0,0,0 +units=m +no_defs]
Number of points: 3103
Data attributes:
part.a part.b dist soil ffreq
Min. :0.0000 Min. :0.0000 Min. :0.0000 1:1665 1: 779
1st Qu.:0.0000 1st Qu.:0.0000 1st Qu.:0.1193 2:1084 2:1335
Median :0.0000 Median :1.0000 Median :0.2715 3: 354 3: 989
Mean :0.3986 Mean :0.6014 Mean :0.2971
3rd Qu.:1.0000 3rd Qu.:1.0000 3rd Qu.:0.4402
Max. :1.0000 Max. :1.0000 Max. :0.9926
> gridded(meuse.grid.proj) <- TRUE
suggested tolerance minimum: 0.737332
Error in points2grid(points, tolerance, round) :
dimension 1 : coordinate intervals are not constant
>
A warning and an error indicates that the projection results in something that
is not on a regular grid.
I don't know what to do but to read some more of the documentation for sp,
rgdal, etc.
Hopefully somebody comes up with something that helps us.
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<mailto:fr...@vestas.com>
http://www.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<http://www.vestas.com/legal/notice>
If you have received this e-mail in error please contact the sender.
From: Bea GD [mailto:aguitatie...@hotmail.com]
Sent: 16. april 2014 11:00
To: Frede Aakmann Tøgersen; r-help@r-project.org
Subject: Re: [R] netCDF to raster and spatial projection
Hi Frede,
Thanks so much for your reply!
I've tried what you said but I get the following error:
Error in spTransform(rasterDF1, crs("+init=epsg:21781")) :
load package rgdal for spTransform methods
I've checked search() and rgdal is before sp.
> search()
[1] ".GlobalEnv" "package:chron" "package:sm" "package:rgeos"
[5] "package:maptools" "package:ncdf" "package:rgdal"
"package:raster"
[9] "package:sp" "tools:rstudio" "package:stats"
"package:graphics"
[13] "package:grDevices" "package:utils" "package:datasets"
"package:methods"
[17] "Autoloads" "package:base"
Also, when I do library("rgdal") I get this message:
> library("rgdal")
rgdal: version: 0.8-16, (SVN revision 498)
Geospatial Data Abstraction Library extensions to R successfully loaded
Loaded GDAL runtime: GDAL 1.10.1, released 2013/08/26
Path to GDAL shared files:
C:/Users/bgonzale/Documents/R/win-library/3.0/rgdal/gdal
GDAL does not use iconv for recoding strings.
Loaded PROJ.4 runtime: Rel. 4.8.0, 6 March 2012, [PJ_VERSION: 480]
Path to PROJ.4 shared files:
C:/Users/bgonzale/Documents/R/win-library/3.0/rgdal/proj
Maybe the problem is something to do with this? I don't know how to fix it.
I'd like to provide you with some data, how would be the best way to post/sahre
a raster?
Thanks!
On 16.04.2014 10:17, Frede Aakmann Tøgersen wrote:
Hi Beatriz
Try to skip this step
# Reprojecting into CH1903_LV03
# First, change the coordinate reference system (crs)
proj4string(rasterDF1) <- "+init=epsg:21781"
And just do this
# Second, reproject the raster
rasterDF1.CH <- spTransform(rasterDF1, crs("+init=epsg:21781"))
Also there is a spTransform both in the rgdal and sp packages. So are they
masking each other? rgdal should be before sp in the search() list.
I cannot be of more help since you provided no data.
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<mailto: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<http://www.vestas.com/legal/notice>
If you have received this e-mail in error please contact the sender.
-----Original Message-----
From: r-help-boun...@r-project.org<mailto:r-help-boun...@r-project.org>
[mailto:r-help-boun...@r-project.org]
On Behalf Of Beatriz R. Gonzalez Dominguez
Sent: 16. april 2014 08:22
To: r-help@r-project.org<mailto:r-help@r-project.org>
Subject: [R] netCDF to raster and spatial projection
I've recently started using R for spatial data. I'd be really grateful
if you could could help me with this. Thanks!
Sorry I don't provide a reproducible example. Please ask me if you have
any questions about the data.
I've extracted data from a multidimensional netCDF file. This file had
longitude, latitude and temperature data (for 12 months of a specific year).
From this netCDF I've got a data frame for January with these
variables: longitude, latitude, temperature.
With this data frame I've created a raster.
# Packages
library("sp")
library("raster")
library("rgdal")
library("ncdf")
library("maptools")
library("rgeos")
library("sm")
library("chron")
# Dataframe to raster
# Create spatial points data frame
coordinates(tmp.df01) <- ~ lon + lat
# Coerce to SpatialPixelsDataFrame
gridded(tmp.df01) <- T
# Coerce to raster
rasterDF1 <- raster(tmp.df01)
> print(tmp.df01)
class : SpatialPixelsDataFrame
dimensions : 103, 241, 24823, 1 (nrow, ncol, npixels, nlayers)
resolution : 0.02083333, 0.02083333 (x, y)
extent : 5.739583, 10.76042, 45.73958, 47.88542 (xmin, xmax,
ymin, ymax)
coord. ref. : NA
names : TabsM_1
min values : -18.1389980316162
max values : 2.26920962333679
There is no value for 'coord. ref.'
The projection of the original netCDF was WGS84. So I gave this
projection to the raster.
proj4string(rasterDF1) <- "+proj=longlat +datum=WGS84 +ellps=WGS84
+towgs84=0,0,0"
Then, I wanted to reproject my raster to another projection:
# Reprojecting into CH1903_LV03
# First, change the coordinate reference system (crs)
proj4string(rasterDF1) <- "+init=epsg:21781"
# Second, reproject the raster
rasterDF1.CH <- spTransform(rasterDF1, crs("+init=epsg:21781"))
At this point I get the following error:
Error in spTransform(rasterDF1, crs("+init=epsg:21781")) :
load package rgdal for spTransform methods
But the package rgdal is already uploaded! It must be something wrong in
the code!
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-
guide.html
and provide commented, minimal, self-contained, reproducible code.
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
