<html><head></head><body><div class="gmail_quote">Tod Fitch <Tod@FitchDesign.com> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail">On Tue, November 26, 2013 1:57 pm, Ian Dees wrote:<br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;">On Tue, Nov 26, 2013 at 3:51 PM, Florian Lohoff <f@zz.de> wrote:<br /><br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;">On Tue, Nov 26, 2013 at 12:30:25PM -0700, Martijn van Exel wrote:<br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #8ae234; padding-left: 1ex;">Hi all,<br /><br />I'm new to this list so please bear with me.<br />The relation editor currently only parses 'forward' and 'backward'<br />roles when considering the visual representation in the rightmost<br />column. In the United States, north/south and east/west are very<br />common as member roles for road routes, because that is how they are<br />officially signposted.</blockquote><br />I would be very
careful in using this. Is this really "south" e.g.<br />180° ? Or is it more like 99° ? Or 269° ?<br /><br />Most streets are not strictly on the 90° raster and signposts are<br />only rough directions.<br /><br />Addings this to OSM might make it much more difficult for Data Consumers<br />to process and interpret data.</blockquote><br /><br />No, these aren't compass directions. They're the directionality of the<br />road. For example, this way is part of the I-94 interstate going west, but<br />a compass in a car driving on it would tell the viewer they were pointing<br />north:<br /><br /><a href="http://www.openstreetmap.org/browse/way/39372612">http://www.openstreetmap.org/browse/way/39372612</a></blockquote><br />Perhaps images like these, found nearly at random on the web, will<br />illustrate typical motorway and highway marking in the US.<br /><br /><a
href="http://farm5.staticflickr.com/4030/5145458837_d192798a62_o.jpg">http://farm5.staticflickr.com/4030/5145458837_d192798a62_o.jpg</a><br /><a href="http://www.interstate80.info/i80_nevada_lettsign.jpg">http://www.interstate80.info/i80_nevada_lettsign.jpg</a><br /><br />Road directionality is based on the total length of the highway.<br />So if the interstate (motorway) is 3000km long and generally<br />more east/west than north/south it will have east/west markings<br />on it even in areas where it is going north/south or even<br />reversing itself for a short distance and going west/east.<br /><br />Marking the directionality in the relation would make it easier<br />for creating navigation instructions that match what the driver<br />sees on the ground (e.g. "turn left on to ramp for I-10 west").<br /><br />Tod<br /><br /><hr /><br />Talk-us mailing list<br />Talk-us@openstreetmap.org<br /><a
href="https://lists.openstreetmap.org/listinfo/talk-us">https://lists.openstreetmap.org/listinfo/talk-us</a><br /></pre></blockquote></div><br clear="all">Adding to the confusion, you have two conflicting schemes in use in the USA. The Interstate highways are referred to as East/West/North/South according to the direction a particular side of the highway is going, so that I-40 W and I-40 E are opposing sides of a divided highway. You also have compass-point letters used to distinguish between branches of the same route. For example, US 31 runs north/south. A portion of it branches off as US 31W, which runs roughly parallel, some miles westward of US 31, and eventually merges back into it.<br>
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-- <br>
John F. Eldredge -- john@jfeldredge.com<br>
"Darkness cannot drive out darkness: only light can do that.<br>
Hate cannot drive out hate: only love can do that."<br>
Dr. Martin Luther King, Jr.<br>
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