LIBKML not accessible to sf

[emochoa]

I am using the st_read function in sf to read a KML file. As in #499, the result has the appropriate geometry but is missing all of its variables and instead has 'Name' and 'Description' fields.

Following advice in #499, I reinstalled GDAL (upgrading to 2.4.2).

From the terminal, I can verify that LIBKML is installed:

> ogrinfo --formats | grep KML
LIBKML -vector- (rw+v): Keyhole Markup Language (LIBKML)
KML -vector- (rw+v): Keyhole Markup Language (KML)

But sf does not seem to have access to LIBKML, only KML:

> st_drivers() %>% filter(name == 'KML' | name == 'LIBKML')
   name        long_name              write  copy  is_raster  is_vector  vsi
1  KML Keyhole Markup Language (KML)  TRUE   FALSE   FALSE      TRUE     TRUE

I have uninstalled and reinstalled both GDAL (using Homebrew) and sf (using devtools), even rebooting in between every step, and still LIBKML is not accessible to sf.

Here's what I'm running:
OS X 10.12.6
RStudio 1.0.153
R 3.5.3
GDAL 2.4.2
sf 0.7-7

If you have any advice, please, I would very much appreciate it. Thank you for your time and consideration. Please let me know if you need any additional information.

[edzer]

Maybe check here: r-spatial/stars#202 (comment)

[ar-puuk]

Hi @emochoa, did you find a solution to this? I have the same issue.

The discussion linked in the reply comment flies above my head. I am using:
Windows 11 26100.2605,
R 4.4.2,
RStudio 2024.12.0 Build 467,
sf 1.0-20, GEOS 3.12.2, GDAL 3.9.3, PROJ 9.4.1; sf_use_s2() is TRUE

[rsbivand]

@ar-puuk Note that GDAL provides two drivers, KML https://gdal.org/en/stable/drivers/vector/kml.html#vector-kml and LIBKMLhttps://gdal.org/en/stable/drivers/vector/libkml.html . The latter needs GDAL built with the libkml library, which is not included in Windows binary builds IIRC. You may read and write kml files with the simpler (and better aligned with simple features) KML driver. If you need libkml, you'll have to build GDAL from source against that library yourself, which sounds like more than you are prepared to do.

[ar-puuk]

@rsbivand, the reason I am looking to use LIBKML instead of KML driver is because loading a kml file into an sf object clumps all the attributes together into a single "Description" column. For now, I have been converting KML to SHP using QGIS and then importing to R as an sf object, which has been inefficient for iterative tasks.

As with the first post on this issue, the GDAL I installed using OSGeo4W contains the LIBKML driver (if my understanding is correct).

system("ogrinfo --version")
# GDAL 3.9.3, released 2024/10/07
# [1] 0

system("ogrinfo --formats", intern = TRUE) |> grep("KML", x = _, value = TRUE)
# [1] "  LIBKML -vector- (rw+v): Keyhole Markup Language (LIBKML) (*.kml, *.kmz)"
# [2] "  KML -vector- (rw+v): Keyhole Markup Language (KML) (*.kml)"  

Is there a way for me to use the Windows installation of GDAL (that includes LIBKML) with sf?

sf::sf_extSoftVersion()
#          GEOS           GDAL         proj.4 GDAL_with_GEOS     USE_PROJ_H           PROJ 
#      "3.12.2"        "3.9.3"        "9.4.1"         "true"         "true"        "9.4.1" 

sf::st_drivers(what = "vector", "KML")
#     name                     long_name write  copy is_raster is_vector  vsi
# KML  KML Keyhole Markup Language (KML)  TRUE FALSE     FALSE      TRUE TRUE

[rsbivand]

However, sf is not, and cannot be, built as a statically linked Windows binary package against GDAL from OSGeo4W. So your use of OSGeo4W is the best you can do.

Maybe use the OSGEO4W ogr2ogr command line program run from the OSGeo4W shell to convert from KML to something sf can read.

R (Rtools) uses UCRT and MXE cross-complied libraries, OSGeo4W uses versioned CRT, they are not compatible.