convert KML file into shape file or CSV file
Almost, in my sleepiness I left out an important part from that pseudo
code. You need to store the data in a variable/object and then write it out.
importeddata <- readOGR("pathtofile",layer.kml)
writeOGR(importeddata ,"pathtooutput",driver="ESRI
Shapefile",layer=output.shp)
Make sure to read the help for both of those commands to get them correct.
Also, unless you're going to do some manipulation in R between those
steps, it's really a indirect method compared to ogr2ogr.
Alex
rusers.sh wrote:
It is the problem of the file. I should have thought of this because i
have tried several tools. Thanks.
Based on your replies, i think it is easy to convert the files between KML
and SHP if the files are correct and have simple structure. We only
need readOGR and writeOGR in rgdal package to do that. Something like the
following arguments.
#Convert KML to SHP
readOGR("pathtofile",layer.kml)
writeOGR("pathtooutput",driver="ESRI Shapefile",layer=output.shp)
#Convert SHP to KML
readOGR("pathtofile",layer.shp)
writeOGR("pathtooutput",driver="KML",layer=output.kml)
Right?
Thanks a lot.
2009/12/9 Barry Rowlingson <b.rowlingson at lancaster.ac.uk>
On Wed, Dec 9, 2009 at 1:22 AM, rusers.sh <rusers.sh at gmail.com> wrote:
Hi all, Does anybody know how to import a KML file in R and them save it as a shape or CSV file. Take the following KML file as an example, http://www.nature.com/nature/googleearth/avianflu1.kml I have tried several extentions of ARCGIS,e.g.KML2Shape,KMLCSVConverter,KMLCSVConverter and XToolsPro, but unfortunately failed to do that. I didnot find a method to solve it in R. If this cannot be done in R, i'd like to see your alternative method to
do
that. Any help or suggestions are greatly appreciated.
As well as the validation problems reported by Alex Mandel, the structure of this KML file isn't appropriate for straight conversion to a shape or CSV file. It has several parts, some "NetworkLink" structures without URLs that just provide some HTML info boxes, and some network link structures that point to other kmz files. You can download these kmz files, unzip them, and possibly convert them to other formats. For example, one of the links is to: http://www.declanbutler.info/Flumaps1/4_Human_cases/Maps_of_human_cases_by period/Cases_by_period1.kmz which when unzipped produces doc.kml and some png files for markers. ogrinfo tells us: $ ogrinfo doc.kml Had to open data source read-only. INFO: Open of `doc.kml' using driver `KML' successful. 1: Data (3D Point) 2: Data (3D Point) 3: Data (3D Point) 4: Data (3D Point) 5: Data (3D Point) 6: Data (3D Point) 7: Data (3D Point) 8: Data (3D Point) - which is a bit weird, 8 layers all called 'Data'. That makes it hard to extract individual layers by name. So I edited the file and renamed them Data to Data8.... I can then read them in R:
data2=readOGR("doc.kml","Data2")
plot(data2)
I can then use writeOGR to create shapefiles, but it's easier on the command line: $ mkdir shapefile $ ogr2ogr -f "ESRI Shapefile" shapefile doc.kml So there's umpteen things going on here, above and beyond any possible structural problems with the KML in the first place: 1. The original KML file points to a bunch of KMZ files, and readOGR isn't going to do all that work for you. 2. Even if it could do all that work, the KML is a complex structure with all sorts of geographic and no-geographic entities and so it can't bung it all into a simple shapefile 3. The individual KMZ files which do contain the data have multiple layers. 4. The layers within a KMZ file (or at least, the one I bothered to look at) have identical names which breaks stuff. Otherwise, it's easy! :) Barry