[R-sig-Geo] writeRaster to ascii file (.asc)
Mauricio Zambrano-Bigiarini
mauricio.zambrano at jrc.ec.europa.eu
Thu Jul 18 11:27:46 CEST 2013
On 07/13/2013 01:44 AM, Robert J. Hijmans wrote:
> I do not the data have changed. Wrong min and max values are reported,
> however. Seems to me that in this case gdal does not know the min and
> max values but reports -2147483648, 2147483647. You could check with
> GDALinfo. I guess that this is a shortcoming of (your version of?)
> gdal, not rgdal. Robert
Just in case still be useful.
I tried to reproduce the wrongly reported values for min and max using
an .asc file I'm using, but I couldn't:
------------ START -----------
library(raster)
# entering to the directory where the .asc file is stored
# setwd("~")
# Creation of a raster file for testing
r <- raster("temp2.asc")
# rgdal: version: 0.8-10, (SVN revision 478)
# Geospatial Data Abstraction Library extensions to R successfully loaded
# Loaded GDAL runtime: GDAL 1.9.2, released 2012/10/08
# Path to GDAL shared files: /usr/share/gdal
# Loaded PROJ.4 runtime: Rel. 4.8.0, 6 March 2012, [PJ_VERSION: 480]
# Path to PROJ.4 shared files: (autodetected)
# Summary of the original raster file
summary(r)
# temp2
# Min. 2.668977e-02
# 1st Qu. 1.474479e-01
# Median 2.109602e-01
# 3rd Qu. 4.575650e-01
# Max. 7.108980e+00
# NA's 1.690500e+04
# Writing the raster from memory to disk (as a new file)
writeRaster(r, filename="temp2_new.asc", format="ascii",overwrite=TRUE)
# class : RasterLayer
# dimensions : 254, 262, 66548 (nrow, ncol, ncell)
# resolution : 5000, 5000 (x, y)
# extent : -1045000, 265000, -620000, 650000 (xmin, xmax, ymin, ymax)
# coord. ref. : NA
# data source : /home/hzambran/temp2_new.asc
# names : temp2_new
# reading the .asc file form disk
r2 <- raster("temp2_new.asc")
# Summary of the .asc file in the hard disk
summary(r2)
# temp2_new
# Min. 2.668977e-02
# 1st Qu. 1.474479e-01
# Median 2.109602e-01
# 3rd Qu. 4.575650e-01
# Max. 7.108980e+00
# NA's 1.690500e+04
# the same summary values are the same as for the original raster (r)
------------ END -----------
I'm using the same rgdal version of Manuel (0.8-10), so as Roger
mentioned before, the error should come from your GDAL version. I'm
using GDAL 1.9.2, released 2012/10/08 (not the latest...)
Kind regards,
Mauricio
--
=================================================
Water Resources Unit
Institute for Environment and Sustainability (IES)
Joint Research Centre (JRC), European Commission
webinfo : http://floods.jrc.ec.europa.eu/
=================================================
DISCLAIMER:
"The views expressed are purely those of the writer
and may not in any circumstances be regarded as sta-
ting an official position of the European Commission"
=================================================
"The journey is the reward" (Steve Jobs)
>
> On Thu, Jul 11, 2013 at 5:04 AM, Manuel Spínola <mspinola10 at gmail.com> wrote:
>> Thank you Mauricio.
>>
>>> sessionInfo()
>> R version 3.0.1 (2013-05-16)
>> Platform: x86_64-apple-darwin10.8.0 (64-bit)
>>
>> locale:
>> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>>
>> attached base packages:
>> [1] grid stats graphics grDevices utils datasets methods
>> base
>>
>> other attached packages:
>> [1] SDMTools_1.1-13 dismo_0.8-11 raster_2.1-37 rgdal_0.8-10
>> maptools_0.8-25
>> [6] lattice_0.20-15 sp_1.0-11 foreign_0.8-54
>>
>> loaded via a namespace (and not attached):
>> [1] tools_3.0.1
>>
>>
>> 2013/7/11 Mauricio Zambrano-Bigiarini <mauricio.zambrano at jrc.ec.europa.eu>
>>
>>> On 10/07/13 18:38, Manuel Spínola wrote:
>>>
>>>> Dear list members,
>>>>
>>>> I am trying to export a raster file to a ascii file (.asc) but the min and
>>>> max values are not the same. Any idea why?
>>>>
>>>
>>> Hi Manuel,
>>>
>>> Could you provide your sessionInfo() ?
>>>
>>>>
>>>> bio1res
>>>>>
>>>> class : RasterLayer
>>>> dimensions : 382, 407, 155474 (nrow, ncol, ncell)
>>>> resolution : 0.008333333, 0.008333333 (x, y)
>>>> extent : -85.95, -82.55833, 8.041667, 11.225 (xmin, xmax, ymin,
>>>> ymax)
>>>> coord. ref. : NA
>>>> data source : in memory
>>>> names : bio1_23
>>>> values : 47, 272 (min, max)
>>>>
>>>> writeRaster(bio1res, filename="temp.asc", format="ascii",overwrite=TRUE)
>>>>>
>>>> class : RasterLayer
>>>> dimensions : 382, 407, 155474 (nrow, ncol, ncell)
>>>> resolution : 0.008333333, 0.008333333 (x, y)
>>>> extent : -85.95, -82.55833, 8.041667, 11.225 (xmin, xmax, ymin,
>>>> ymax)
>>>> coord. ref. : NA
>>>> data source : /Users/manuelspinola/Dropbox/**DistribucioÌ n de
>>>>
>>>> especies/World_Clim_Costa_**Rica/temp.asc
>>>> names : temp
>>>> values : -2147483648, 2147483647 (min, max)
>>>>
>>>
>>> Unfortunately, your example is not reproducible, so I tried with a
>>> different example and the values in the original and the written ascii file
>>> were the same (rgdal_0.8-10, raster_2.1-48, sp_1.0-11):
>>>
>>> ---------- START --------------
>>> library(raster)
>>> Loading required package: sp
>>>
>>> # Creation of a raster file for testing
>>> r <- raster(system.file("external/**test.grd", package="raster"))
>>>
>>> r
>>> #class : RasterLayer
>>> #dimensions : 115, 80, 9200 (nrow, ncol, ncell)
>>> #resolution : 40, 40 (x, y)
>>> #extent : 178400, 181600, 329400, 334000 (xmin, xmax, ymin, ymax)
>>> #coord. ref. : +init=epsg:28992 +towgs84=565.237,50.0087,465.**
>>> 658,-0.406857,0.350733,-1.**87035,4.0812 +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 : /usr/lib64/R/library/raster/**external/test.grd
>>> #names : test
>>> #values : 128.434, 1805.78 (min, max)
>>>
>>> writeRaster(r, filename="temp.asc", format="ascii",overwrite=TRUE)
>>> #rgdal: version: 0.8-10, (SVN revision 478)
>>> #Geospatial Data Abstraction Library extensions to R successfully loaded
>>> #Loaded GDAL runtime: GDAL 1.9.2, released 2012/10/08
>>> #Path to GDAL shared files: /usr/share/gdal
>>> #Loaded PROJ.4 runtime: Rel. 4.8.0, 6 March 2012, [PJ_VERSION: 480]
>>> #Path to PROJ.4 shared files: (autodetected)
>>> #class : RasterLayer
>>> #dimensions : 115, 80, 9200 (nrow, ncol, ncell)
>>> #resolution : 40, 40 (x, y)
>>> #extent : 178400, 181600, 329400, 334000 (xmin, xmax, ymin, ymax)
>>> #coord. ref. : NA
>>> #data source : /home/zambrhe/temp.asc
>>> #names : temp
>>>
>>> # reading the .asc file form disk
>>> r2 <- raster("temp.asc")
>>>
>>> r2
>>> #class : RasterLayer
>>> #dimensions : 115, 80, 9200 (nrow, ncol, ncell)
>>> #resolution : 40, 40 (x, y)
>>> #extent : 178400, 181600, 329400, 334000 (xmin, xmax, ymin, ymax)
>>> #coord. ref. : NA
>>> #data source : /home/zambrhe/temp.asc
>>> #names : temp
>>>
>>> # Summary of the ascii file in the hard disk
>>> #summary(r2)
>>> # temp
>>> #Min. 128.4340
>>> #1st Qu. 293.2325
>>> #Median 371.4120
>>> #3rd Qu. 499.8195
>>> #Max. 1805.7800
>>> #NA's 6097.0000
>>>
>>>
>>> # Summary of the original raster file
>>> summary(r)
>>> # test
>>> #Min. 128.4340
>>> #1st Qu. 293.2325
>>> #Median 371.4120
>>> #3rd Qu. 499.8195
>>> #Max. 1805.7800
>>> #NA's 6097.0000
>>> ---------- END --------------
>>>
>>> Kind regards,
>>>
>>> Mauricio Zambrano-Bigiarini, Ph.D
>>>
>>> --
>>> ==============================**===================
>>> Water Resources Unit
>>> Institute for Environment and Sustainability (IES)
>>> Joint Research Centre (JRC), European Commission
>>> TP 261, Via Enrico Fermi 2749, 21027 Ispra (VA), IT
>>> Work Phone : +39 0332 789588
>>> webinfo : http://floods.jrc.ec.europa.**eu/<http://floods.jrc.ec.europa.eu/>
>>> ==============================**===================
>>> DISCLAIMER:
>>> "The views expressed are purely those of the writer
>>> and may not in any circumstances be regarded as sta-
>>> ting an official position of the European Commission"
>>> ==============================**===================
>>> "The journey is the reward" (Steve Jobs)
>>>
>>>
>>> _______________________________________________
>>> R-sig-Geo mailing list
>>> R-sig-Geo at r-project.org
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>
>>>
>>
>>
>> --
>> *Manuel Spínola, Ph.D.*
>> Instituto Internacional en Conservación y Manejo de Vida Silvestre
>> Universidad Nacional
>> Apartado 1350-3000
>> Heredia
>> COSTA RICA
>> mspinola at una.ac.cr
>> mspinola10 at gmail.com
>> Teléfono: (506) 2277-3598
>> Fax: (506) 2237-7036
>> Personal website: Lobito de río <https://sites.google.com/site/lobitoderio/>
>> Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/>
>>
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>>
>>
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