[R-sig-Geo] write/readOGR issue with date / time strings

[Corrie Curtice]

> sessionInfo()
R version 2.13.1 (2011-07-08)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)

locale:
[1] C/en_US.UTF-8/C/C/C/C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] rgdal_0.7-1 sp_0.9-84

loaded via a namespace (and not attached):
[1] grid_2.13.1     lattice_0.19-30 tools_2.13.1

I installed rgdal and PROJ4 as follows:

setRepositories(ind=1:2)
install.packages("rgdal")
install.packages("PROJ.4")



Thanks,

Corrie



On 11/11/11 5:31 PM, "Roger Bivand" <Roger.Bivand at nhh.no> wrote:

>On Fri, 11 Nov 2011, Corrie Curtice wrote:
>
>> Hello,
>>
>> Apologies if this has already been addressed somewhere, I did a brief
>>search
>> of archives but didn't find quite this issue.
>
>Which versions of what are you using? You should provide the output of
>sessionInfo(), the messages given when rgdal loads, and details of how
>you 
>installed rgdal. In addition, a use case would be helpful, but only when
>we know what version you are using. In current rgdal, data frame columns
>of class POSIXt are converted to character strings before writing with
>writeOGR().
>
>Roger
>
>>
>> I'm writing out an ESRI shapefile.  My spdf has a date/time field.
>>Looks
>> like this:
>>
>>> head(spdfUTM at data)
>>           krillGMTtime          Lat          Lon
>> 1   2010-05-12 12:34:21 -64.67655969 -62.15040195
>> 21  2010-05-12 12:35:12  -64.6771229  -62.1519511
>> 38  2010-05-12 12:36:02 -64.67775863 -62.15340614
>> 57  2010-05-12 12:36:53 -64.67838269 -62.15494829
>> 78  2010-05-12 12:37:43 -64.67901497 -62.15647203
>> 100 2010-05-12 12:38:37 -64.67973667 -62.15773224
>>
>> All three fields are reported to be "factors" by str.  writeOGR appears
>> happy:
>>
>>> writeOGR(spdfUTM,dd,layer="krillPoints-UTM",driver="ESRI
>> Shapefile",verbose=TRUE,overwrite=TRUE)
>> $object_type
>> [1] "SpatialPointsDataFrame"
>> $output_dsn
>> [1] "/users/corriecurtice/documents/Data_2010/Shapefiles/"
>> $output_layer
>> [1] "krillPoints-UTM"
>> $output_diver
>> [1] "ESRI Shapefile"
>> $output_n
>> [1] 11179
>> $output_nfields
>> [1] 3
>> $output_fields
>> [1] "krillGMTtime" "Lat"          "Lon"
>> $output_fclasses
>> [1] 4 4 4
>> $dataset_options
>> NULL
>> $layer_options
>> NULL
>> Warning message:
>> In writeOGR(spdfUTM, dd, layer = "krillPoints-UTM", driver = "ESRI
>> Shapefile",  :
>>  existing layer removed
>>
>> When I read it right back in again, the date/time field is NAs.  This is
>> also true if I load the shapefile into ArcMap.
>>
>>> foo <- readOGR(dd,layer="krillPoints-UTM",verbose=TRUE)
>> OGR data source with driver: ESRI Shapefile
>> Source: "/users/corriecurtice/documents/Data_2010/Shapefiles/", layer:
>> "krillPoints-UTM"
>> with 11179 features and 3 fields
>> Feature type: wkbPoint with 2 dimensions
>>
>>> head(foo at data)
>>  krillGMTti          Lat          Lon
>> 1       <NA> -64.67655969 -62.15040195
>> 2       <NA>  -64.6771229  -62.1519511
>> 3       <NA> -64.67775863 -62.15340614
>> 4       <NA> -64.67838269 -62.15494829
>> 5       <NA> -64.67901497 -62.15647203
>> 6       <NA> -64.67973667 -62.15773224
>>
>> Thoughts? Am I missing something obvious?
>>
>> I can break it up into separate date and time fields, but since the
>>field is
>> simply a factor anyways I'm not sure how that would help.
>>
>> Cheers,
>>
>> Corrie
>>
>> ---
>> Corrie Curtice
>> Research Analyst
>> Marine Geospatial Ecology Lab
>> Nicholas School of the Environment, Duke University
>> http://mgel.env.duke.edu
>> em: corrie.curtice at duke.edu
>> ph: 252-504-7538
>>
>>
>>
>>
>>     [[alternative HTML version deleted]]
>>
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>>
>
>-- 
>Roger Bivand
>Department of Economics, NHH Norwegian School of Economics,
>Helleveien 30, N-5045 Bergen, Norway.
>voice: +47 55 95 93 55; fax +47 55 95 95 43
>e-mail: Roger.Bivand at nhh.no
>