Latest Contributions by JaySandhu

‎07-28-2017

>Our actual objective is to determine the performance impact if the real world operation was/was not segmented (namely the difference in impedance). In that case, you need to carefully determine a way to measure the real world operation to compare between different simulations. For example, Location-Allocation may be used to locate warehouses, but then the Vehicle Routing Problem (VRP) solver is used to make the actual daily deliveries from the chosen warehouse. In that case one would measure the performance (on-time, minimize costs, etc) from the delivery operations for a few days runs to see if the locations are good. But I know you understand what you are measuring. Regards, Jay Sandhu

‎07-25-2017

In location-allocation minimize impedance type, we minimize the sum of weighted impedance. That is, demand weight multiplied by the impedance to the facility. So you should only compare weighted impedance. If demand weight is all one's, then you can compare sum of impedance. >No we are not fixing any of the facilities at any point (not sure what this would show?). Go to the whole solution. Make the chosen facilities from Run2a and Run2b "required" and solve. Now you are taking the solution found in the subset and solving in the whole. You can now compare the solution quality found in the subsets with the one from running whole. That is, compare the sum of weighted impedance before and after you made the facilities required. This will give you a way to compare the results of the subsets with the whole. Jay Sandhu

‎07-25-2017

I see the picture with the subset. It is solving quite a bit different problem so there is no guarantee the solution will be the same. However I am not sure you will consistently see an improvement by doing subsets. So given the above picture, you are solving for 2 and then in the subset you are solving for 1 each? How are you comparing the results? What metric? Do you take the chosen facilities from the subsets and make them required in the whole and resolve to compare? Do note that Maximize capacitated coverage has a different objective then minimize impedance. Sometimes they give the same answer. (for coverage the goal is to cover the most demand within the cutoff honoring facility capacities).

‎07-24-2017

What solver are you using? Location-Allocation? If yes, it uses heuristics to solve the problem. If you change problem space, you may get a slightly different answer. From your post, it is not clear how you model it "broken into smaller parts". Are the number of candidates still the same? Are cutoffs still the same? How different are the results? Jay Sandhu

‎07-20-2017

If you open the input Stops attribute table, it has a field called Sequence that tells you the order in which the stops were visited. You can export out that table as needed. Jay Sandhu

‎07-19-2017

You have to change the time of day for the route layer and resolve. You can do this using python. Take a look at page 20 of this Esri Dev Summit proceedings to do exactly this: http://proceedings.esri.com/library/userconf/devsummit17/papers/dev_int_94.pdf Jay Sandhu

‎07-07-2017

Yes. When you make the OD layer, you can set it's properties to accumulate any other attributes besides the one you solve on. See the screen shot where I am accumulating the Miles attribute on the OD layer properties page. Do note that when you solve on travel time, and accumulate the length attribute, it will the length of the path that was chosen while minimizing travel time. It is not doing two solves to get the minimum travel time and minimum length. Jay Sandhu

‎07-07-2017

If you are solving on travel time then the cutoff has to be specified in travel time. So you could give a slightly larger cutoff, say 120 minutes and then filter the output by discarding any rows that are larger than 100 miles. There is not a way to load "pairs" in OD. You can create individual 1 by N OD matrices where you load N destinations that are within 100 miles and solve that one OD and export the results to a table. Then repeat for the next origin from your 8024 origins (reuse the same OD layer, delete the origin and load the next one). But this only makes sense if you are able to write a script to automate this workflow. I think you should be able to load all the origins and destinations in one OD, set a cutoff and solve. the output will only be the pairs that are within the cutoff. It will not generate the full OD matrix, only a partial one. Another thing to do with the OD layer is to set the output lines to None. So even the straight lines are not generated. But that said, the output is still very large (24 million rows) and if you are using ArcMap which is 32 bit app and limited to 2 GB RAM, it may not work. You could try making a model of this (make OD layer, load locations, set the properties/cutoffs, solve, export results to a output table) and then solving this model with Background 64 bit GP. This will give it more RAM to run in and may work. Otherwise you may have to split this into 4 OD layers with one-fourth the origins in each layer and solve, and concatenate the results. OR, you should get ArcGIS Pro 2.0 which is a 64 bit app and will use all the RAM and will solve much larger ODs. Jay Sandhu

‎07-07-2017

Currently the directions GP tool does not output 3D coordinates. Jay Sandhu

‎07-07-2017

The route solver when used with "heuristics" such as use hierarchy or use the avoid/prefer restrictions is no longer solving the shortest path. So I am glad you verified that you do get the shortest path when these things are not being used. Avoid/prefer have their use in cases like avoid a certain area unless that is the only way to get to it such as a gated community. You can obviously scale the costs as well. If you only have a few edges to scale, then another way is to use scaled cost line barriers. You can scale them above or below 1. The use case there is slow downs due to weather conditions or accidents. The advantage is that you do not have to edit/rebuild the network as these are applied to the route analysis layers. Jay Sandhu

‎07-06-2017

When you solve on Length, the route is minimized for that attribute. It can additionally report the sum of another attribute like exposure along that path. But it is not trying to minimize exposure. When you switch to solving on exposure, it will find a different path based on minimizing exposure and honoring whatever other things you may set like restrictions, etc. You cannot compare the two paths for the "accumulated" attributes and infer that something is wrong. The question is, given that you solved on length, is the path returned correct? Similarly, if you solved it on exposure, is the resulting path correct? If not, make sure you are setting up the impedances, restrictions and connectivity policy correctly.

‎07-05-2017

Setting the edge with Oneway to N will prevent it from being traveled. But as you mention, this and adding turns requires being able to edit the data and then rebuild the network dataset. If you cannot edit the network data then you can only use the barrier approach that I had mentioned earlier.

‎07-05-2017

Yes, you can always add turn restriction to prevent travel from blue to red edges. You can read more on that here: About creating a turn feature—Help | ArcGIS Desktop About editing turn features—Help | ArcGIS Desktop

‎07-03-2017

Goal of restrictions is to restrict the places they touch the network edges. So in this case, the red line touches the two blue lines and they will be restricted. So you could do one of two things if you want to restrict the red but not the blue: 1. Place a point restriction on the red line. So only the red line will be restricted. To generate a point on a line, you can use the GP tool Feature to Point with the inside option. It will create a point at the midpoint of that line. 2. Or, make the red line shorter on both ends before you load it in as a line restriction. Jay Sandhu

‎07-02-2017

You are using the right tool, OD Cost Matrix. But your network is not set up correctly to find the paths. Did you try the Service Area lines to see if your network is connected? How about the network identify? One more thing to check: the locations you are using as your origins and destinations, are they included as a source in the network? If yes, then you need to remove them as a source. Generally you only need the line edges as a source in the network. If you add point locations as a source, they may be disconnected from the network and when you load the same points origins and destinations then they may not find any paths. Jay Sandhu

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My Ideas

Latest Contributions by JaySandhu

Re: Geographically splitting a problem into smaller chunks, produces lower total impedance.

Re: Geographically splitting a problem into smaller chunks, produces lower total impedance.

Re: Geographically splitting a problem into smaller chunks, produces lower total impedance.

Re: Geographically splitting a problem into smaller chunks, produces lower total impedance.

Re: Obtain an Ordered List of Stops in ArcGIS Network Analyst Routing Tool

Re: Hello, I am using the ‘Make Route Layer’ tool. Usually, I manually enter the optional ‘Start Time’. However, I have a field in a table where different start times are stored. Is there a way of automatically feeding these different start times to the ‘

Re: OD Cost Matrix

Re: OD Cost Matrix

Re: 3D network and z coordinates from direction tool

Re: Network Analyst Route Impedence Producing Strange Results

Re: Network Analyst Route Impedence Producing Strange Results

Re: How to exclude endpoints of line restrictions?

Re: How to exclude endpoints of line restrictions?

Re: How to exclude endpoints of line restrictions?

Re: Cannot connect all origins to destinations using OD cost tool

Re: Creating a maximum walkshed around each point

Re: Closest Facility - Remove Facilities and Incid...

Re: Polygons for Best Dump Site By Site Cost and T...

Re: Delay in routes

Re: Delay in routes