[R-sig-Geo] convert KML file into shape file or CSV file

[Alex Mandel]

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
>>
> 
> 
>