https://grasswiki.osgeo.org/w/index.php?action=history&feed=atom&title=Vector_break_line_intersections 2026-04-05T05:07:36Z Revision history for this page on the wiki MediaWiki 1.41.0 https://grasswiki.osgeo.org/w/index.php?title=Vector_break_line_intersections&diff=23636&oldid=prev 2016-10-03T09:24:30Z

<p>Draft FAQ from https://lists.osgeo.org/pipermail/grass-user/2016-September/074866.html</p> <p><b>New page</b></p><div>== Example of breaking a vector line at intersections ==<br /> <br /> Q: I have a vector line map (river network) which I want to clean and break the lines at intersections. How to manage the categories?<br /> <br /> A: Using GRASS v.clean tool:<br /> <br /> # Cleaning vector and breaking lines<br /> v.clean -c --overwrite input=river_network_modified output=river_network_modified_clean tool=break,snap,rmline threshold=0,50,0<br /> <br /> # Check cats<br /> v.category input=river_network_modified_clean option=report layer=-1<br /> <br /> Now add new categories to a new layer, e.g. with<br /> <br /> v.category option=add layer=2 cat=1 step=1 type=line ...<br /> <br /> Then add a new table to layer 2<br /> <br /> v.db.addtable layer=2 columns=&quot;cat_lyr1 integer&quot; ...<br /> <br /> Load category values (or any other attributes) from layer 1 to layer 2 with<br /> <br /> v.to.db layer=2 column=cat_lyr1 query_layer=1 query_column=cat ...<br /> <br /> Now you have unique new categories in layer 2 and the old categories still existing in layer 1 are also in the field ''cat_lyr1'' of layer 2.<br /> <br /> [[Category: FAQ]]<br /> [[Category:Vector]]</div>

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