writeOGR to GPX file: empty table
On Mon, 17 May 2010, Agustin Lobo wrote:
Roger, There is actually information in the file, i.e. the first point is: <?xml version="1.0"?> <gpx version="1.1" creator="GDAL 1.6.3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ogr="http://osgeo.org/gdal" xmlns="http://www.topografix.com/GPX/1/1" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd"> <wpt lat="41.800745980899059" lon="2.359550956673553"> <extensions> <ogr:Comentario>4</ogr:Comentario> <ogr:Rcvr_Type>Juno ST</ogr:Rcvr_Type> <ogr:GPS_Date>2009/10/27</ogr:GPS_Date> <ogr:GPS_Time>03:09:11pm</ogr:GPS_Time> <ogr:Datafile>AILANTO27102009.SSF</ogr:Datafile> <ogr:GPS_Height>1089.392</ogr:GPS_Height> <ogr:Northing>4627933.603</ogr:Northing> <ogr:Easting>446791.833</ogr:Easting> <ogr:PDOP_max>0</ogr:PDOP_max> <ogr:HDOP_max>0</ogr:HDOP_max> <ogr:Fecha_GPS>0000/00/00</ogr:Fecha_GPS> <ogr:PosNofilt>0</ogr:PosNofilt> <ogr:Pos_filt>0</ogr:Pos_filt> <ogr:Semana_GPS>0</ogr:Semana_GPS> <ogr:Segundo_GP>0</ogr:Segundo_GP> <ogr:Altura_GPS>0</ogr:Altura_GPS> <ogr:Prec_vert>0</ogr:Prec_vert> <ogr:Prec_horz>0</ogr:Prec_horz> <ogr:Dev_Tp>0</ogr:Dev_Tp> <ogr:Norte>0</ogr:Norte> <ogr:Este>0</ogr:Este> <ogr:Abundancia>4</ogr:Abundancia> </extensions> </wpt> Cannot read it in R. Maybe I'm not using the appropriate settings for dsn and layer (I've tried many alternatives):
The variants are as described in the readOGR help file, that is layer= "waypoints", "tracks", "routes", "track_points", or "route_points". Maybe reading the help page might save time?? Roger PS. I think that the OGR GPX driver expects a number of fields that are most often absent when reading (so generating NULL/NA), and may not handle other extra user-defined fields gracefully. If need be, create a short string in the NAME or name field to concatenate the data you need, that is work around apparent shortcomings in the driver.
writeOGR(AilantMSY09WGS84LL, dsn="/media/TRANSCEND/MONTSENY2008/MONTSENY_GEODATA/FloraExotica2009/AilantMSY09R.gpx",layer="AilantMSY09R",driver="GPX",dataset_options="GPX_USE_EXTENSIONS=YES")
test <- readOGR(dsn="/media/TRANSCEND/MONTSENY2008/MONTSENY_GEODATA/FloraExotica2009/AilantMSY09R.gpx",layer="AilantMSY09R")Error in ogrInfo(dsn = dsn, layer = layer, input_field_name_encoding = input_field_name_encoding) :
Cannot open layer Agus
Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: Roger.Bivand at nhh.no