[R-sig-Geo] Problem Setting Projection of Rasters upon Import

[Michael Sumner]

Please report on the actual code you ran, you've just sent two
messages, one with

test<-raster("us_ppt_1981_2010.02.asc", crs="+ellps=GRS80")

this correctly cannot set the CRS and so it is NA

and the other with

t<-raster("us_ppt_1981_2010.02.asc", crs="+proj=longlat +ellps=GRS80")
> test

We have no idea what you see in "t" now. In short you have to have a
"+proj", not just a "+ellps" for this incantation. You can check with

library(rgdal)
CRS("+ellps=GRS80")
Error in CRS("+ellps=GRS80") : projection not named






On Fri, Jul 12, 2013 at 11:10 AM, Michael Treglia <mtreglia at gmail.com> wrote:
> I just tried running it in an older version of R, 2.13.0 (64-bit) and it
> ran with no problem... the exact same code run from Notepad++
>
> Anybody know what has changed/if I need to adjust my for R 3.x.x?
>
> t<-raster("us_ppt_1981_2010.02.asc", crs="+proj=longlat +ellps=GRS80")
>> test
> class       : RasterLayer
> dimensions  : 3105, 7025, 21812625  (nrow, ncol, ncell)
> resolution  : 0.008333333, 0.008333333  (x, y)
> extent      : -125.0208, -66.47917, 24.0625, 49.9375  (xmin, xmax, ymin,
> ymax)
> coord. ref. : +proj=longlat +ellps=GRS80
> values      : D:\GIS\PRISM\1981-2010\PPT\us_ppt_1981_2010.02.asc
>
> Thanks again!
> Mike
>
>
> On Thu, Jul 11, 2013 at 5:59 PM, Michael Treglia <mtreglia at gmail.com> wrote:
>
>> Hi Erin,
>>
>> Thanks for the quick response - I did try it with the plus sign, and same
>> result. (I also tried it with 'crs="+proj=longlat +ellps=GRS80"' with the
>> same result too.)
>>
>>
>> >  test<-raster("us_ppt_1981_2010.02.asc", crs="+ellps=GRS80")
>> >  test
>> class       : RasterLayer
>> dimensions  : 3105, 7025, 21812625  (nrow, ncol, ncell)
>> resolution  : 0.008333333, 0.008333333  (x, y)
>> extent      : -125.0208, -66.47917, 24.0625, 49.9375  (xmin, xmax, ymin,
>> ymax)
>> coord. ref. : NA
>> data source : D:\GIS\PRISM\1981-2010\PPT\us_ppt_1981_2010.02.asc
>> names       : us_ppt_1981_2010.02
>> values      : -2147483648, 2147483647  (min, max)
>>
>> I'm running R Version 3.0.0, 64-bit, in case that helps at all...
>> Cheers,
>> Mike
>>
>>
>> On Thu, Jul 11, 2013 at 5:50 PM, Hodgess, Erin <HodgessE at uhd.edu> wrote:
>>
>>> Hi Michael:
>>>
>>> Did you try this;
>>>
>>> test<-raster("us_ppt_1981_2010.02.asc", crs="+ellps=GRS80")
>>>
>>> with the plus sign, please?
>>>
>>> That might do it.
>>>
>>> Thanks,
>>> Erin
>>>
>>> ________________________________________
>>> From: r-sig-geo-bounces at r-project.org [r-sig-geo-bounces at r-project.org]
>>> on behalf of Michael Treglia [mtreglia at gmail.com]
>>> Sent: Thursday, July 11, 2013 7:16 PM
>>> To: r-sig-geo at r-project.org
>>> Subject: [R-sig-Geo] Problem Setting Projection of Rasters upon Import
>>>
>>> Hi All,
>>>
>>> I am using he "raster" package, and in particular the "raster" function. I
>>> am dealing with a number of layers, and it would be easiest to set the CRS
>>> upon import. Looking through the documentation, it seems that it is
>>> doable,
>>> and I have been using the following code to get started, though it is not
>>> setting the CRS.
>>>
>>> Here are my code, and the results of the import:
>>> > test<-raster("us_ppt_1981_2010.02.asc", crs="ellps=GRS80")
>>> > test
>>> class       : RasterLayer
>>> dimensions  : 3105, 7025, 21812625  (nrow, ncol, ncell)
>>> resolution  : 0.008333333, 0.008333333  (x, y)
>>> extent      : -125.0208, -66.47917, 24.0625, 49.9375  (xmin, xmax, ymin,
>>> ymax)
>>> *coord. ref. : NA *
>>> data source : D:\GIS\PRISM\1981-2010\PPT\us_ppt_1981_2010.02.asc
>>> names       : us_ppt_1981_2010.02
>>> values      : -2147483648, 2147483647  (min, max)
>>>
>>> If I use the "projection" command afterwards, it sets the projection
>>> appropriately though.
>>> > projection(test)<-CRS("+proj=longlat +ellps=GRS80")
>>> > test
>>> class       : RasterLayer
>>> dimensions  : 3105, 7025, 21812625  (nrow, ncol, ncell)
>>> resolution  : 0.008333333, 0.008333333  (x, y)
>>> extent      : -125.0208, -66.47917, 24.0625, 49.9375  (xmin, xmax, ymin,
>>> ymax)
>>> *coord. ref. : +proj=longlat +ellps=GRS80 *
>>> data source : D:\GIS\PRISM\1981-2010\PPT\us_ppt_1981_2010.02.asc
>>> names       : us_ppt_1981_2010.02
>>> values      : -2147483648, 2147483647  (min, max)
>>>
>>> Any suggestions of why the first option is not working? I have a script in
>>> which I import all files in a folder, and the simplest way to assign the
>>> projection would be the first option (I'm using an 'lapply' command).
>>> It would look something like this:
>>> import <- lapply(filenames ,raster, crs="....") #where "filenames" is a
>>> vector of filenames in the working directory.
>>>
>>> In case it helps, these are PRISM Climate Data, and the header of my
>>> raster
>>> file is this:
>>> ncols 7025
>>> nrows 3105
>>> xllcorner -125.020833333333329
>>> yllcorner 24.062500000000000
>>> cellsize 0.008333333333333
>>> NODATA_value -9999
>>>
>>> Thanks for any suggestions!
>>> Mike
>>>
>>>         [[alternative HTML version deleted]]
>>>
>>> _______________________________________________
>>> R-sig-Geo mailing list
>>> R-sig-Geo at r-project.org
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>
>>
>>
>
>         [[alternative HTML version deleted]]
>
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-- 
Michael Sumner
Hobart, Australia
e-mail: mdsumner at gmail.com