[R-sig-Geo] Combing attribute table with polygon??

Zia Ahmed zua3 at cornell.edu
Thu Jan 28 03:29:33 CET 2010


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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