Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
Lines may need to be snapped with v.clean tool=snap,break,rmdupl.
Boundaries may need to be cleaned with v.clean tool=break,rmdupl,rmsa repeatedly until the rmsa tool (Remove small angles at nodes) no longer modifies any boundaries. If vector topology is still not clean, boundaries may also need to be snapped with v.clean tool=snap,break,rmdupl.
When using the -e flag, v.patch shifts category (cat) values in the output so that category numbers from the different input maps do not overlap. This shift is applied to both the category values of the features and the category values in the attribute tables. Hence, there is no need to run v.category and v.db.update beforehand.
When using the -a flag, the user has to make sure that the features in the different maps added to the output map do not have overlapping category numbers, unless identical category numbers reflect identical attributes, otherwise the attributes of the added maps are lost. To avoid this, the user can use v.category option=sum to change category values of some of the maps before patching.
v.patch input=geology,streams out=geol_streams
g.copy vect=roads,transport v.patch -a input=railroads output=transport --overwrite
Available at: v.patch source code (history)
Latest change: Wed Mar 31 23:39:01 2021 in commit: d6a1ec5fa9a6faaaf35eb34231d44ed724b8c8e7
Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
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© 2003-2023 GRASS Development Team, GRASS GIS 7.8.8dev Reference Manual