[R-sig-Geo] Filtering shapefile to come up with only one county

[Roger Bivand]

On Sat, 5 Apr 2014, Yuster Ronoh wrote:

> Thanks Gordon and Kapo. Gordon I tried your code and it plot the whole
> country  but for Kapo it work well and I manage to plot Nakuru county but I
> still have problem in exporting shapefile here in the error message:
>
> writeOGR(Nakuru,dsn="C://Users/symon/Desktop/gis/",layer="Nakuru",driver="ESRI
> Shapefile")Error in writeOGR(Nakuru, dsn =
> "C://Users/symon/Desktop/gis/", layer = "Nakuru",  :
>  Creation of output file failed

This is a known problem under Windows, the dsn should read:

"C:/Users/symon/Desktop/gis"

with no trailing directory separator. Can be replicated with:

library(rgdal)
td <- tempdir()
dsn <- system.file("vectors", package = "rgdal")[1]
cities <- readOGR(dsn=dsn, layer="cities")
td
writeOGR(cities, paste(td, "/", sep=""), "cities",
  driver="ESRI Shapefile")
# Error in writeOGR(cities, paste(td, "/", sep = ""), "cities",
#  driver = "ESRI Shapefile") :
#  Creation of output file failed
writeOGR(cities, td, "cities", driver="ESRI Shapefile")
# works

Roger

>
>
>
>
> On Sat, Apr 5, 2014 at 1:16 AM, Kapo Coulibaly <kmcoulib at gmail.com> wrote:
>
>> Something like this works for me:
>> counties<-readOGR(dsn=""C://Users/symon/Desktop/gis/",layer="counties")
>> Nakuru<-subset(counties,COUNTY_NAM=="Nakuru") # make sure the name and the
>> content of the columns are spelled correctly
>> plot(Nakuru) # Plots the county map
>>
>>
>> You can write the shapefile of Nakuru county with:
>> writeOGR(Nakuru,dsn=""C://Users/symon/Desktop/gis/",layer="Nakuru",driver="ESRI
>> Shapefile")
>>
>>
>>
>> On Fri, Apr 4, 2014 at 1:25 PM, Yuster Ronoh <yuster0 at gmail.com> wrote:
>>
>>> Dear List members
>>> I have a Kenya shapefile with counties.I try to come up with Nakuru county
>>> map and I try with the below code and got an error.How do i  sub-set to
>>> come up with Nakuru shapefile from the Kenya shapefile
>>> here is my code:
>>>
>>>> library(maps)
>>>
>>>> library(maptools)
>>>
>>>> library(sp)
>>>
>>>> library(rgdal)
>>>
>>>> library(ggplot2)
>>>
>>>> counties<-readShapePoly("C://Users/symon/Desktop/gis/counties.shp")
>>>
>>>> str(counties)
>>>
>>>> Nakuru <- fortify(counties, region = "COUNTY_NAM")
>>>> str(Nakuru)
>>>> unique(counties at data$COUNTY_NAM)
>>>
>>>> class(counties)
>>>
>>>> counties at data = counties at data[counties at data$COUNTY_NAME != "NAKURU",]
>>>
>>>> plot(counties at data)Error in plot.window(...) : need finite 'xlim'
>>> valuesIn addition: Warning messages:1: In min(x) : no non-missing arguments
>>> to min; returning Inf2: In max(x) : no non-missing arguments to max;
>>> returning -Inf3: In min(x) : no non-missing arguments to min; returning
>>> Inf4: In max(x) : no non-missing arguments to max; returning -Inf
>>>
>>>
>>>         [[alternative HTML version deleted]]
>>>
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>>>
>>
>>
>
> 	[[alternative HTML version deleted]]
>
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-- 
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; fax +47 55 95 91 00
e-mail: Roger.Bivand at nhh.no