[R-sig-Geo] Shows error when I try to write shape file-Re: Combing attribute table with polygon??

[Zia Ahmed]

Hi, Roberts,
In my last mail, I mentioned it works fine,  but when I try write shape 
file after merging it shows error. I think I need to  define  spatial 
object or data frame after merging. I do not know  how to do this. 
Thanks again.
Zia

 > poly.data1 = merge(poly.data, data.table, by="MUKEY" ,all.x = TRUE)
 > names(poly.data1) # polygoan
 [1] "MUKEY"      "AREASYMBOL" "SPATIALVER" "MUSYM"      "Sand"     
 [6] "Silt"       "Clay"       "pH"         "CEC"        "EC"       
[11] "SAR"        "CaCO3"      "SOM"        "BD"         "AWC"      
[16] "KSAT"       "Kf"         "Kw"         "LL"         "LEP"      

 >polyShp <- "D:/test/mapunit_poly.shp" 
 > writeOGR(poly.data1, dsn=polyShp, layer="mapunit_poly", driver="ESRI 
Shapefile")
Error in writeOGR(poly.data1, dsn = polyShp, layer = "mapunit_poly", 
driver = "ESRI Shapefile") :
  obj of wrong class

Zia Ahmed wrote:
> Thank you so much Roberts! it works.
>
> Zia
>
> Robert J. Hijmans wrote:
>> Zia, something like this might work as long as MUKEY has no NA values:
>>
>> poly.data = merge(poly.data, data.table, by="MUKEY" ,all.x = TRUE)
>>
>> Robert
>>
>> On Wed, Jan 27, 2010 at 1:58 PM, Zia Ahmed <zua3 at cornell.edu> wrote:
>>  
>>> I have created one data table and one polygon in R. Both have a 
>>> similar type
>>> of column.  I want to combine or join them with this column or field
>>> ("MUKEY").  Then  I will convert this polygon  as  a ESRI  shape file.
>>> But  when  I  used  spCbind,   I got error. I think i miss something 
>>> here.
>>> Is there any way join attribute table with polygon? Thanks
>>> Zia
>>>
>>> poly.data1 <- spCbind(poly.data, data.table)
>>> Error in spCbind(poly.data, data.table) : different numbers of rows
>>>
>>>
>>> names(poly.data) # polygoan
>>> [1] "AREASYMBOL" "SPATIALVER" "MUSYM"      "MUKEY"    > 
>>> names(data.table) #
>>> data
>>> [1] "MUKEY" "Sand"  "Silt"  "Clay"  "pH"    "CEC"   "EC"    "SAR"   
>>> "CaCO3"
>>> [10] "SOM"   "BD"    "AWC"   "KSAT"  "Kf"    "Kw"    "LL"    "LEP"
>>>    
>>>> length(poly.data$MUKEY)
>>>>       
>>> [1] 76969
>>>    
>>>> length(data.table$MUKEY)
>>>>       
>>> [1] 184
>>>     poly.data1 <- spCbind(poly.data, data.table)
>>>
>>> combinedShp1 <- "D:/test/combined1.shp" writeOGR(poly.data1,
>>> dsn=combinedShp1, layer="combined1", driver="ESRI Shapefile")
>>>
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>>>
>>>
>
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