After running v.patch, the header file will contain only information taken from the first input file name given in the string input=name,name, ..., with the exception of the geographic region's edge information, and the scale and threshold information. (The user's current geographic region settings are ignored; this information is instead extracted from the vector file headers.) In the new composite vector map layer, the boundaries of the geographic region will be expanded to encompass all of the geographic area included in the map layers being patched, and the scale will be set equal to the smallest (i.e., most gross) scale used by any of the patched map layers (this will affect default node-snapping thresholds). The map threshold is calculated automatically from the map scales given in the file headers, and (currently) is not used directly. The composite vector map layer's header will probably need to be edited; this can be done from within the GRASS program v.digit.
Los programas v.mkgrid y v.mkquads pueden servir para asegurar que los bordes de los mapas se alinean correctamente.
Las lineas que se dupliquen en el mapa resultado (límites de polígono por jemplo) deben ser editadas usando v.digit o eliminadas posteriormente.
Tras la ejecución de v.patch debe ejecutarse v.support para crear el fichero dig_plus (topología). En ese momento puede establecerse un umbral de tolerancia para unir nodos.