I have some prexisting data in dbf format for a very large area (Australia sized plus much larger, around 2.8 GiB in size) (can be converted quite easily to xml or shapefile)
I want to download and retain openstreetmap data and remove the dbf data when it overlaps selected tags for ways, nodes and relations. This can be done quite easily in JOSM and the re-exported. But JOSM does not like large files certainly not 2.8 GiB ones.
Is there any way to remove unnecessary tags and data from the downloaded OSM file and then split the two files, my dataset and the OSM downloaded dataset into roughly equally sized (in area) regions enough that JOSM could handle (with 1.2 GiB of RAM the software limit on my PC for JOSM). I was thinking of doing something with QGIS, as it seems the most powerful and user friendly. I'm no good at non GUI software but am open to suggestions.
A further issue when splitting files is what happens when one part of a relation or way is on one side of the split and another on the other side