On 01/02/2011 12:54 PM, Joshua Wiley wrote:
Dear Gaja,
If "sp" and "maptools" are not already installed, you'll need to do
that. It is often recommended that you update your existing packages
before installing new ones. Once that is done (or if you have
already), then you just need to load the packages, and then R will be
able to find the readShapeSpatial() function (it is in the 'maptools'
package). Something like this should get you going:
########################
update.packages()
install.packages(c("sp", "maptools"))
require(sp)
require(maptools)
?readShapeSpatial #documentation
towns<- readShapeSpatial("OB/OB.shp")
############################
Hi,
I have also been trying to read a shapefile:
SS10aAust.shp
with readOGR (rgdal)
and readShapeSpatial (maptools)
with absolutely no success, despite having long lost count of the help
pages I have read seeking an example of how to do this:
readOGR("/home/jim/research/ombo/mapping/SSD10aAust.shp",
layer="cities")
Error in ogrInfo(dsn = dsn, layer = layer, input_field_name_encoding =
input_field_name_encoding) :
Cannot open layer
I realize that one has to supply a layer here, but searching through the
four files that were extracted from the ZIP file, there is no mention of
layers. Obviously guessing on the basis of other examples doesn't work
either.
ozmap<-readShapeSpatial(
"/home/jim/research/ombo/mapping/SSD10aAust.shp")
Error in getinfo.shape(fn) : Error opening SHP file
All of the examples seem to deal with a different type of shape file
that follows whatever rules are operating in these two functions. All of
the examples and tutorials I have found on the Web are similarly
inscrutable.
I guess I should start with asking how does one discover what layers are
included in a shapefile? One step at a time...
Jim
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