Analysis with country borders factored in

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08-30-2012 07:23 AM
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New Contributor
Hi there,

I'm new to ArcGIS and testing its capabilities for possible implementation in a global logistics company.

I'm wondering if there is a way to easily factor country borders into network analysis.  To avoid customs delays, we omit service links, or drives from our analysis that cross nation borders in most cases (US to MEX, US to CAN), but allow it in other areas where cross border travel can be done without incident (EU nations). 

So right now I'm messing around with the service area layers...If for instance I wanted to generate a polygon in Detroit that doesn't spill over the border into Ontario and vice versa, how might this be done?

I appreciate the help in advance.

Thanks,

JR
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This comes down to two things, I think.  First, do you have access to edit your network dataset?  And second, should travel be completely restricted into the other country, or do you want to model the customs delays?

Access to the network dataset

If you can update the features of the network, then I would suggest adding a segment of road at each of the border crossings with a cost that includes the expected delay at that border crossing.  This way, every analysis will include the delays properly.
 
If you can only update the schema of the network, you can add a restriction attribute that either prohibits or avoids a specific country.  In this case, you would have to turn the restrictions on or off for a given analysis.

No access to the network dataset

In this case, as Joe said, you will want to use barriers, but barriers come with a few caveats. 

First, they have to be applied to each analysis you do.  You'll have to load them into every analysis layer you create that should respect the border barriers.

Also, they can slow down your analysis.  Depending on the scale of analysis you do, it might not matter, but there is extra processing done to ensure that a good path can be found near barriers.  This only applies to hierarchical routes.  In order not to disconnect the hierarchy with a barrier, the hierarchy filtering around the barriers is relaxed.  This means more searching and more time.

If you don't have access to your network dataset or you don't mind a little slow-down, then barriers are your choice.  To completely restrict travel across borders, you can load country borders as line restriction barriers.  To model customs delays, you can load additive point barriers at places where you would encounter border crossings.  With additive barriers, travel will be allowed across them, but additional cost will be added to the route.   This could be useful when a route with a customs delay is still faster than the next best route without the delay.


Summary

In summary, if maximum performance is a necessity and you can edit your network, then model the cost delays explicitely in the network.  Otherwise, either use additive point barriers at the border crosses to model the delay, or use a line barrier to restrict travel across a border.

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Hi there,

I'm new to ArcGIS and testing its capabilities for possible implementation in a global logistics company.

I'm wondering if there is a way to easily factor country borders into network analysis.  To avoid customs delays, we omit service links, or drives from our analysis that cross nation borders in most cases (US to MEX, US to CAN), but allow it in other areas where cross border travel can be done without incident (EU nations). 

So right now I'm messing around with the service area layers...If for instance I wanted to generate a polygon in Detroit that doesn't spill over the border into Ontario and vice versa, how might this be done?

I appreciate the help in advance.

Thanks,

JR


You should be able to lay down a barrier at the border.
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This comes down to two things, I think.  First, do you have access to edit your network dataset?  And second, should travel be completely restricted into the other country, or do you want to model the customs delays?

Access to the network dataset

If you can update the features of the network, then I would suggest adding a segment of road at each of the border crossings with a cost that includes the expected delay at that border crossing.  This way, every analysis will include the delays properly.
 
If you can only update the schema of the network, you can add a restriction attribute that either prohibits or avoids a specific country.  In this case, you would have to turn the restrictions on or off for a given analysis.

No access to the network dataset

In this case, as Joe said, you will want to use barriers, but barriers come with a few caveats. 

First, they have to be applied to each analysis you do.  You'll have to load them into every analysis layer you create that should respect the border barriers.

Also, they can slow down your analysis.  Depending on the scale of analysis you do, it might not matter, but there is extra processing done to ensure that a good path can be found near barriers.  This only applies to hierarchical routes.  In order not to disconnect the hierarchy with a barrier, the hierarchy filtering around the barriers is relaxed.  This means more searching and more time.

If you don't have access to your network dataset or you don't mind a little slow-down, then barriers are your choice.  To completely restrict travel across borders, you can load country borders as line restriction barriers.  To model customs delays, you can load additive point barriers at places where you would encounter border crossings.  With additive barriers, travel will be allowed across them, but additional cost will be added to the route.   This could be useful when a route with a customs delay is still faster than the next best route without the delay.


Summary

In summary, if maximum performance is a necessity and you can edit your network, then model the cost delays explicitely in the network.  Otherwise, either use additive point barriers at the border crosses to model the delay, or use a line barrier to restrict travel across a border.

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Joe and Patrick,

Thanks both for your help.  Laying line barriers seems to be the best solution for me for now!  But out of curiosity, is there an easily explainable way to load the barriers as country borders as you suggested?

Thanks again,

JR
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If you are truly just beginning to use Network Analyst, then before you do anything else, do the tutorial:

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/About_the_ArcGIS_Network_Analyst_tutor...

It only takes an hour or so and goes through all of the basics of working with the software.

So, assuming you did the tutorial, and assuming you are working in ArcMap and that you have a map with a service area layer and a country borders layer, do this:

Right click on the Restrictions sub section of the Line Barriers class in your NA window.
Choose Load Locations.
Pick your country borders from the drop down called Load from.
Click ok.

It is similar to the Adding facilities step of exercise 4 of the tutorial.
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