Rationale: GRASS GIS 7 comes with an updated vector format (see new features). In order to use older vector data (from GRASS GIS 6) in GRASS GIS 7 the user has to rebuild the topology. Additionally it is recommended to switch the database backend from DBF files to SQLite. Both can be done in an automated way per MAPSET as described below. To become readable in GRASS 7, all vector maps in a mapset need to be updated to the improved vector file format (i.e., rebuild the topology with v.build.all along with the change to the SQLite database backend (SQLite is the new default in GRASS 7 instead of DBF in GRASS 6, using db.connect and v.db.reconnect.all). Q: I found a tutorial for GRASS GIS 6 which is based on the North Carolina sample dataset. Do I have to convert that myself? A: No, you can simply download an updated North Carolina sample dataset for GRASS GIS 7 from here: http://grass.osgeo.org/download/sample-data/ Source.