# Changes

,  8 years ago
== Oddities ==
Sometimes you will find two roads which cross where one does not quite line up exactly from one side to the other.
There are a few things we need to look at in this situation.
1.) # Do the roads actually line up in reality? If so we need to modify the junction to be a basic 4 way junction. 2.) # Do the roads ALMOST line up in reality? If you were giving instructions to a person and would tell them to go straight with no mention of any slight turn or jog, then we want to make it into a 4 way junction. You may need to "split the difference" and not follow the centerline of either road to achieve this. The angles are exaggerated in this next example to show how the junction is forced to be close to 90 degrees, then we taper to the true centerlines of the roads. In practice this can be much more gradual and/or only done while zoomed in very close. <br/>[[Image:Jct_4_offset_align.png]]<br/> 3.) # Finally, is there a true separation between the roads? Would you need to say for example "turn left then make an immediate right"? If so then we will want to leave the junction such that the two sides do not align. Since we want to avoid very short segments of road, it may be wise to shift the side roads as far apart from each other as possible with them still in the proper location (along the far curb lines for a residential street for example). This will maximize the length of the short segment between the side roads.
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