Discussion: mapping bridge or tunnel
in: Orienteering; General
Oct 30, 2012 5:28 PM
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There is this tall viaduct of a 4-lane road that goes across this wide ravine. How to map it ? there is a symbol for tunnel available on OCAD, and it could be used the wide trail located below the viaduct, but it doesn't look realistic, as it is not a tunnel. Or, use symbols often used in road cartography to indicate a bridge or viaduct, as shown here in red lines and anchoring ends. But there is no such "bridge" symbol on OCAD.
what to do?
what to do?
Oct 30, 2012 5:46 PM
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If it is ISSOM (sprint) there is the symbol 512.1 Bridge that is exactly what you have only black.
Oct 30, 2012 7:13 PM
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Have seen the odd debate on nopesport: http://forum.nopesport.com/viewtopic.php?f=1&t=112...
Oct 30, 2012 8:31 PM
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andrew: that was great, interesting discussion. Yeah, another problem I have is that the 4-lane road on the viaduct is wide enough that it actually covers some interesting mappable features on the ground beneath it. And at the same time, the bridge has two pedestrian sidewalks that are possibly an excellent route choice to avoid the climb down and up.
Oct 30, 2012 8:43 PM
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sherpes: In that case I think I would map the ground, break the mapping of the road there to show the bottom of the ravine as the main running level and connect the two ends of the bridge with the Sprint Standard symbol 708.1 crossing section to show that you can go across. That symbol does show up in the ISSOM symbol set in newer versions of OCAD.
Oct 30, 2012 10:26 PM
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I don't know, I think you've got to be careful with the idea of using ISSOM symbols and concepts on an ISOM map. And doubly careful with using red markup.
Some points: The red markup symbol (already used in sherpe's demo), looks too much like ISOM 707, uncrossable boundary. Thus, as mapped it would be forbidden for a runner to pass under the bridge. Save the red markup for the course setting stage - after you've decided whether runners will be passing under the bridge or over the bridge.
The underpass symbol (518), is extendible to arbitrary length (518.0 in OCAD). Yes, the short English translation reads tunnel - but if you read the ISOM description, the functionally takes precedent (a passageway under a road or railway). I would suggest replacing your "red lines with anchoring ends" with an elongated version of symbol 518. You're already using 518 locally around the road, but if there is a broader region where you expect runners to pass through, this symbol should be extended.
I would suggest that mappable features under the bridge are probably not worth mapping - unless they significantly impede passage. Places such as this are always ambiguously mapped, and probably shouldn't be used for control points.
Also - even though OCAD by default gives pavement (brown 50%) priority over contour lines (brown 100%), I prefer a mapping style where counters are overprinted above pavement. This convention is less common, but if it is used, you can more easily see whether a road follows the contours of the ground or maintains a constant elevation across a gully. This is important route-choice information. Also, you can sometimes bend your contours or use earth banks, to indicate where the road is lying on earth, where there is a discontinuity, and whether the runner can easily pass over the road.
Some points: The red markup symbol (already used in sherpe's demo), looks too much like ISOM 707, uncrossable boundary. Thus, as mapped it would be forbidden for a runner to pass under the bridge. Save the red markup for the course setting stage - after you've decided whether runners will be passing under the bridge or over the bridge.
The underpass symbol (518), is extendible to arbitrary length (518.0 in OCAD). Yes, the short English translation reads tunnel - but if you read the ISOM description, the functionally takes precedent (a passageway under a road or railway). I would suggest replacing your "red lines with anchoring ends" with an elongated version of symbol 518. You're already using 518 locally around the road, but if there is a broader region where you expect runners to pass through, this symbol should be extended.
I would suggest that mappable features under the bridge are probably not worth mapping - unless they significantly impede passage. Places such as this are always ambiguously mapped, and probably shouldn't be used for control points.
Also - even though OCAD by default gives pavement (brown 50%) priority over contour lines (brown 100%), I prefer a mapping style where counters are overprinted above pavement. This convention is less common, but if it is used, you can more easily see whether a road follows the contours of the ground or maintains a constant elevation across a gully. This is important route-choice information. Also, you can sometimes bend your contours or use earth banks, to indicate where the road is lying on earth, where there is a discontinuity, and whether the runner can easily pass over the road.
Oct 31, 2012 5:00 AM
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SLOC had a similar highway bridge over the US Relay Champs map last year. I believe their map only showed the bridge pillars and not the bridge itself. I'm assuming from your description that the bridge probably would never be used as a route choice, only underneath.
This discussion thread is closed.