Thanks to Rick and Roger for their respective replies. Both helped.
I updated R, GDAL and rgdal (I now have: R version 2.11.1
(2010-05-31) x86_64-apple-darwin9.8.0 with rgdal_0.6-26).
I then Ricks proposed writeOGR statement below. This works.
After adding some data (a dataframe called Bluegum) to the data already
contained in the SPDF with spCbind like this:
>SPbluegumADD=spCbind(SPbluegumImP,Bluegum)
I get a SpatialPolygonsDataFrame (according to class()) that can be plotted
and looks OK on the plot. I can even use the newly added variables to define
colours in the plot so I am sure the spCbind was successful.
But when I try to write it to a shapefile I get an error again:
> writeOGR(SPbluegumADD,".","SPbluegumImPX",driver="ESRI Shapefile")
Error in writeOGR(SPbluegumADD, ".", "SPbluegumImPX", driver = "ESRI
Shapefile") :
GDAL Error 1: Invalid index : -1
I tried to compare the structure of the objects as Rick adviced by using
list.tree (is there a better way?) and get:
> list.tree(SPbluegumImP, depth=2)
SPbluegumImP = S4 1 (717288 bytes)( SpatialPolygonsDataFrame )
A bbox = double 4= named array 2 X 2= 28.395 -26.388 28.405 ...
A proj4string = S4 1( CRS )
A polygons = list 144
A . ... and 132 more
A plotOrder = integer 144= 4 26 33 6 22 92 ...
A data = list 3( data.frame )
> list.tree(SPbluegumADD, depth=2)
SPbluegumADD = S4 1 (17552624 bytes)( SpatialPolygonsDataFrame )
A bbox = double 4= named array 2 X 2= 28.395 -26.388 28.405 ...
A proj4string = S4 1( CRS )
A polygons = list 144
A . ... and 132 more
A plotOrder = integer 144= 4 26 33 6 22 92 ...
A data = list 24( data.frame )
A . ... and 12 more
The difference seems to be that the SPDF object created by the spCbind
contains something extra. The "A . ... and 12 more" at the end. When I
set the depth in list.tree() to -1 to get everything and look right at the
end I get:
for the original object(SPbluegumImP:
A data = list 3( data.frame )
A . TOWNSHIP = integer 144= category (7 levels)( factor )= BLUEGUM VIEW
BLUEGUM VIEW ...
A . SUBURB = integer 144= category (1 levels)( factor )= BLUEGUM VIEW
BLUEGUM VIEW ...
A . PROPDESC = integer 144= category (5198 levels)( factor )= 116 82 138 11
127 ...
A A row.names = integer 144= 3 85 94 127 166 ...
for the Object created by spCbind (SPbluegumADD)
A data = list 24( data.frame )
A . TOWNSHIP = integer 144= category (7 levels)( factor )= BLUEGUM VIEW
BLUEGUM VIEW ...
A . SUBURB = integer 144= category (1 levels)( factor )= BLUEGUM VIEW
BLUEGUM VIEW ...
A . PROPDESC = integer 144= category (5198 levels)( factor )= 116 82 138 11
127 ...
A . Response.ID = integer 144= category (44327 levels)( factor )=
53cbc1d8-c12a-4aaf-a74f-0037b8e4c577 ...
A . Fieldworker = character 144= Sfiso Jiyane ...
A . Received = integer 144= category (43009 levels)( factor )= 2010/05/01
12:44:16 PM ...
A . Start = integer 144= category (42997 levels)( factor )= 2010/04/13
09:26:10 AM ...
A . End = integer 144= category (43124 levels)( factor )= 2010/04/13
09:26:57 AM ...
A . Duration = integer 144= category (2908 levels)( factor )= 00:00:47
00:01:02 ...
A . Location = integer 144= category (1 levels)( factor )= N/A N/A N/A N/A
...
A . Language = integer 144= category (1 levels)( factor )= English English
...
A . PROPDESC.1 = integer 144= 5 5 5 5 5 5 5 5 ...
A . ... and 12 more
A A row.names = integer 144= 3 85 94 127 166 ...
I cannot see a real difference except that the second object now contains
the additional columns added by spCbind.
Can anyone offer some insight?
regards and thank for the help so far
Christiaan
On 2 June 2010 18:52, rick reeves <ree...@nceas.ucsb.edu> wrote:
> Christian:
>
> Compare the object fields carefully to those in the 'parent' object.
> Assuming that SPbluegumImP is a valid SpatialPolygonsDataFrame,
> you might try simplifying the writeOGR statement to:
>
> writeOGR(SPbluegumImP,".","SPbluegumImP",driver="ESRI Shapefile")
>
> ..which will write the file SPbluegumImP.shp to the current working folder
> (which you can establish with setwd("path"))
>
> You can also send me your file, and I will be glad to have a look.
>
> hope this helps,
> Rick R
>
>
>
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