Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.
Sign up to join this community
In the image below, the system of lines includes 6 segments. This connectivity gives the appearance of an "island" as the internal segments are connected to each other and are not to the outside world.
Given that the geometry is correct and I'm not looking to alter it, in a large line network, how can I identify those groups of lines or "sub networks" that are not connected to the main network?
Buffer your lines by a small amount with the dissolve option set to All. Do not include any dissolve fields so that a single buffer feature is created. Then run the Multipart to Singlepart tool to break the buffer apart into the set of single part polygons that do not actually touch each other. The polygon with the largest area will cover the lines in your core network and all other smaller polygons will cover the lines that make up your "sub networks".
