Latest Contributions by LanoYado

‎11-29-2016

I am using the solver "Minimize Facilities" in the location allocation toolbox, but there is a constraint in my problem the solver doesn't allow me to add it. The constraint is for some nodes, the total demand connected to that specific node is n-1, where n is the total number of nodes or lines connected to that node from the neighbor. This is an extra constraint but I couldn't find any way to include it in my problem. I found a python package called PuLP used for linear programming optimization. Has anyone used it before? Any other toolboxes that can be used for this problem with an option to add mathematic constraints? Thanks in advance

‎11-28-2016

Sorry Abdullah, I didn't get your point. Thanks for your reply.

‎11-28-2016

Thanks Chris for the reply. It does not matter where the new merged node will be as long as keeping all lines connect the individual nodes that form the new node with their neighbors. The new location could be any "old" location of the existing nodes or it could be a central location or any place else. There will not be any constraint on the location of the nodes except keeping the total connection to the neighbors with no change. The lines among merged-nodes, of course, will be deleted; for example, lines: 41-42 and 41-43 will be eliminated while lines 41-11 and 41-56 will be there. Note that a single line is enough to connect the new node to the node 56 although the old lines are two.

‎11-28-2016

I wondered if there is a way to reduce some nodes in a network. For instance, if there are two or more adjacent nodes (orange color), these nodes for my problem can be merged together as single nodes. In the figure below, nodes 41, 42, and 43 can be merged and forms a single node connected to the nodes 11 and 56. Any idea to do so? Thanks Best wishes

‎11-27-2016

I am working on location allocation problem for a network consists of 2000 nodes and 2500 lines. I have found the locations of facilities to cover the whole 2000-demand using minimum facilities solver. I have a case when a node (orange color in the figure) either itself or one of the adjacent nodes can be removed from demand. Which one to be removed is my question; I can remove those orange nodes from my demand and solve for minimum facilities but it is not going to give me a global solution for the problem, instead, some adjacent nodes can be removed (only one adjacent node). Ex: Demand-21 can be removed from the total demand OR demand-20 (adjacent to 21) can be removed OR demand -22 (adjacent to 21). The same is true for the other orange-color demand or their adjacents. Is there any way (using the model builder or a python script) to do so so that the solver finds the minimum number of facilities for the reduced demand? I am asking because I've tried many cases with known results but did not get the global solution for most of them. Thanks for any idea Best regards

‎10-29-2016

Ex: Without facility 10 (I deleted it because I see it extra facility) If line 9-10 is out of service, still demeand-10 has a connection to facility-11. If line 10-11 is out of service, still demand-10 has a connection to facility-9. and so on

‎10-29-2016

I am doing outage analysis on a network using barriers points (Red Points) on the midpoints of lines generated by "Generate points along lines". Make a loop for every outage; each time a barrier is applied on a single line (equal to line outage) and solve the problem to find the minimum facilities I need for the network so that every node (14 points) has connection to at least a facility all time. Combining all results of solving location allocation problem should give me the total minimum facilities to be installed in case of line outage. However, I found that the facilities found from the solution contain some extra ones I can delete them with getting the same access to at least a facility which means it is not minimum solution. Any idea? Note: this question is similar to one I posted recently and asked how to solve location allocation based on facility outage; here we have line outage. Figure 1: My model to solve the problem Figure 2: Result (Black Circle) after running the model

‎10-28-2016

Does that make sense? That is true for the node-33 as well. I found out that these extra facilities are located on points with two lines connected to. Any idea to find those points and delete them? I have a network with more than 2000 nodes which is not easy to find all of these additional facilities.

‎10-28-2016

Thanks Jay and sorry I was not clear in my last comment. I've applied your idea (method 2) on a network with 118 nodes and the last graph was a part of it. I followed your two steps. The red circle points are from step 1 and the red square points are from step 2. Now, there are some facilities (the two red points) I can delete them while still I have for every node of the whole network at least two facilities. For instance, delete node-39 and you will still have at least 2 facilities connected for each node; Point 40 has 3 facilities connected to (40, 42 & 37), Point 37 has 2 facilities (37, 40 & 34) So, the final solution from the two steps is not a minimum optimal solution for locations of facilities because we can delete some of these facilities and get the objective of the problem.

‎10-27-2016

Thanks Jay; that is a brilliant idea I haven't thought about. But still the result shows some extra facilities since we deal with the problem as two different problems and two separate objective functions. For instance, node-33 and node- 39 in the figure below (I applied your steps of method-2) are not necessary to have them for minimization of facilities. Node-33, with having a facility at its location, still can reach a facility, say node-15, while the other one, node-37, in out of service and vice versa. The same thing is true for node-39. You may ask what about the rest neighbor nodes, for example, node-40, if there is no facility at node-39? still node-40 can reach at least one if the other one is lost. I've tried your first method as well but for some reason I did not get any reasonable result; I got a facility at each node of my of network. Thanks Jay and Dan for your ideas.

‎10-26-2016

Thanks Dan. Probably, there's no "direct" solution provided by the network analyst toolbox as for the case of a facility per a demand (minimize the facilitirs). It's the same problem but for the case of contingency or outage n-1 of facilities. That is, solve the problem and find the number of facilities with their locations to minimize the total number of facilities so that every demand has a connection to at least two facilities; just in case one of them is in outage or maintenace but the other one should be in service.

‎10-25-2016

I was reading the Network Analyst Help to see if possible how to assign at least two facilities (Red in the figure; result of analysis) for each demand (Green; data I have) using location allocation tool. I want to find those locations for the facilities so that all demands can reach at least two facilities through only one road. The figure is for the case when one demand can reach at least one facility.The graph is just for example. Any idea? Thanks in advance

‎10-13-2016

Thank Dan.

‎10-13-2016

Thanks Chris, many times, when I ask question here in GeoNet, it shortens the time to me and gives me a right course to read about. I greatly appreciate the helps I got form all here in GeoNet.

‎10-13-2016

If I have points and lines connect them and working in Arcscene, I have an elevation value for each point stored in a field in the point layer. Can I keep the lines connect points when elevate the points? For example, I can create a surface layer from the point based on that field of elevation (for instance, IDW) and then used in Arcscene to elevate the points. I don't want to give the same elevation for the lines because the lines will follow the surface value for all their lengths which make the lines look like curves. I want to keep the lines straight with only giving elevations for their end points. The figure below shows an example of a line (AB) connects the two points A & B with an elevation (C) for B and zero for A. Can I keep the line (AB) connects the two ends A and B but giving an elevation to B with the value C? I other word, AB is the line in 2D and AC is the same line in 3D. Is there any way or tool to do it? Thanks

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My Ideas

Latest Contributions by LanoYado

Linear programming (PuLP) for location allocation

Re: Node reduction

Re: Node reduction

Node reduction

Finding Minimum Facilities for demand with reduction

Re: Line-Outage Analysis Using Barriers

Line-Outage Analysis Using Barriers

Re: Two Facilities for Each Demand

Re: Two Facilities for Each Demand

Re: Two Facilities for Each Demand

Re: Two Facilities for Each Demand

Two Facilities for Each Demand

Re: Connecting lines to points in 3D

Re: UTM for Texas

Connecting lines to points in 3D

Re: UTM for Texas