3 replies to this topic

[DHissemGISCARTO]

I'm working in an area where there is a heavy amount of overlapping multi-lane highways and want to apply graphic styles to define each highway from one another...

Is there an acceptable distance or percentage of separation I can manually apply to the line segments that wouldn't get me in trouble with the perfectionists I always meet?

I prefer seeing the lanes that I am mapping... the roads are part of an inset so rather large scale mapping probably around 5,000 or 7,500

See below

 Highway_Separation.pdf   21.16K   62 downloads

[Dennis McClendon]

Sorry, but I'm having trouble understanding your question. At 1:5000, given any reasonable line weight for the superhighways, side-by-side routes (like the 401 and 407 in Mississauga) should not touch each other. That would only start to be a problem around 1:30 000.

If you mean that the median is not falling in the center of the highway, that's usually solved by generating all the symbology (casing, color stroke, center stroke) from the same centerline file. At 1:5000, you may have different centerlines for westbound and eastbound lanes. On something like the 401 you may have additional centerlines for local and express lanes. If you don't wish to represent those as they come to you, you might have to perform some calculation to derive a new averaged centerline that you can then symbolize.

[DHissemGISCARTO]

Looks like I was able to work around the issue, client told me that it isn't essential to worry about the spacing, that it is more a "look" that he requires then accuracy, not a fan of that proposal but the client has the cloute and the payroll so on I continue with small manual changes as I progress to give the viewer the idea of the divided highway.

But I have learned from what you have posted Dennis and will keep this in mind for any future project invloving these mulit lane requirements... I pretty much figured the averaged centreline and a graphic style that represents a multi lane highway is probably the best bet (as long as the roads do not need attribute data in analysis) This is more a touristy visualization.

Thank you muchly.

[David Medeiros]

Looks like I was able to work around the issue, client told me that it isn't essential to worry about the spacing, that it is more a "look" that he requires then accuracy, not a fan of that proposal but the client has the cloute and the payroll so on I continue with small manual changes as I progress to give the viewer the idea of the divided highway.

But I have learned from what you have posted Dennis and will keep this in mind for any future project invloving these mulit lane requirements... I pretty much figured the averaged centreline and a graphic style that represents a multi lane highway is probably the best bet (as long as the roads do not need attribute data in analysis) This is more a touristy visualization.

Thank you muchly.

Hi Darryl,

Keep in mind that when dealing with tourist maps or even detailed street maps the actual location of medians and lane dividers is not nearly as important as the visual implication of road type, capacity or designation. I know it can be hard when faced with the real world data to eliminate the extra detail but that's what it's all about when translating GIS to production cartography. Keeping those details in may actually be detrimental to the maps efficacy. Always best to design the map to its intended use and publication scale rather than the data scale.