# Changes

## Junction Style Guide

, 5 years ago
updated loop text re:3 parts not 2; updated loop images
Loops are roads that you can enter, and without reversing course, end up at the same place you started.
An important Map Editor rule is: '''a LOOP RULES'''# A road segment must ''not'' start and end on the same junction node'''.(loop back onto itself)# Two segments must not share the same to end junctions# Any loop must be made up of 3 segments
If this rule is these rules are not followed, the routing server will have difficulty in providing routes into and out of the loop. Any loop broken into two three segments by a junction will not have this problem.
Hopefully there will be another roadway along the loop road which you can map, which will break the loop into two pieces. If there are no natural interruptions (side-streets) to the loop and the entire loop is represented by one road segment that connects with itself, we you must [[Map Editing Quick-start Guide#Splitting a segment|insert a superfluous junction node]] along the loop segment. The specific location does not matter, but most people put it near the half-way point of the segment.
'''Here is one example showing a proper 3-segment loop:'''<br />[[File:Jct loop bulbLoop_3-part_1.png]] [[File:Loop_3-part_2.png]] {{clear}}<br />'''This is an example of an improper 2-segment loop:'''<br />[[File:Jct Loop_3-part_3.jpg|center]]{{clear}}<br />'''Here is a side-by-side example of a proper 3-segment loop squareand improper 2-segment loop in a parking lot:'''<br />[[File:Loop_3-part_6.pngjpg|center]]{{clear}}<br />
'''NOTE:''' It is very easy for an editor to find the extra junction node, assume it is truly superfluous, and delete it, when it should remain in place! This problem is magnified if the loop road is large or shaped so it is not obvious that it is a loop. One solution is to identify a path or driveway branching from the loop road and add it to the map, forcing a 3-way junction that would be less likely to be deleted.
'''NOTE:''' The Map Editor may be resistant in editing a loop that does not already follow the rule that it must be broken in two. If you run into saving errors, try one of the following approaches:
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