Latest Contributions by MelindaMorang

It's probably a connectivity problem in your network.  Suppose you have a small chunk of your network that's disconnected from the rest of the network.  If your stop snapped to a network edge in that disconnected portion, then it could be that it isn't possible to travel 800 meters.  The maximum distance you could travel was 169m. Use the Network Identify tool (on the Network Analyst toolbar) to click around on the network edges in the vicinity of the problematic points.  In the pop-up Network Identify box, you can see what other edges are connected to the one you clicked on, so this is an easy way to identify connectivity problems. In order for network edges to connect, there needs to be either an endpoint or a vertex on both features at the location where they touch, depending on your connectivity policy.  You can read more about network connectivity here: ArcGIS Help (10.2, 10.2.1, and 10.2.2) ... View more

A geometric network isn't the same thing as a network dataset.  Geometric networks are usually used for utilities (power, water, etc.), whereas the network dataset is specifically for roads and used in the Network Analyst extension.  Could that be the problem? ... View more

Hello, CY. At this time, there are no plans for a tool to create a GTFS dataset from ArcMap.  One of the main reasons is that most of the data included in the GTFS dataset is not inherently geographical.  stops.txt is the only required file that contains any geographic information at all (the stop locations).  The only other file that includes lat/lon points is shapes.txt.  The rest of the files are a large set of related tables containing information about the schedules.  We don't have any tools to help with scheduling, and table manipulation is probably easier outside of ArcMap. ... View more

You can write such a script using a Geometry Polygon object and some search cursors. See the code sample at the bottom of this page: ArcGIS Help (10.2, 10.2.1, and 10.2.2) ... View more

Thank you so much for your input, Rell. Regarding points that still fall outside the range specified: If this is a consistent problem for you, you can just increase the search tolerance (range).  Is there some other reason increasing the search tolerance wouldn't work for you? Regarding the Ignore Invalid Locations setting: The current ArcMap 10.x behavior is as follows: If "Ignore Invalid Locations" is checked True: The solve succeeds, but it throws a warning message saying 'Location "[blah]" in "Stops" is on a non-traversable network element position.' That location is simply skipped, and the route will bypass it completely. If "Ignore Invalid Locations" is unchecked False: You get the same warning, but the solve fails, and no output is produced. You can also uncheck the "Terminate on Solve Error" option. The tool now always succeeds in running, even if no output is actually produced because the solve failed. So, to summarize: Regardless of your "Ignore Invalid Locations" setting, you can always extract the features that caused the problem from the warning messages.  If you want solve output to be produced, you need to set "Ignore Invalid Locations" to True.  Does that answer your question? The proposed new behavior wouldn't change the "Ignore Invalid Locations" setting, but it would make it much less likely that points would be invalid in the first place.  They wouldn't locate on restricted areas to start with, and if the restrictions and barriers changed after they were located, they would be relocated automatically at solve time. ... View more

Hi Simon.  No, this is not possible with the OD Cost Matrix solver.  The reason OD Cost Matrix is fast is precisely because it doesn't store the "traversal result", the actual network edges and junctions used.  If you need to extract that information, you need to use the Route or Closest Facility solver. ... View more

Topology of the input features is only one possible cause of a poorly-connected network.  Please see the link in my post above about network connectivity.  It could be the way your connectivity groups are set up or your connectivity policy.  Maybe you're using End Point connectivity when you should be using Any Vertex, or maybe you have override vertices but their connectivity policy isn't set to Override. ... View more

I wasn't sure what you were referring to when you asked about the timeframe for "this" to be implemented.  Are you referring to the ability to create and/or edit network dataset properties in python?  If so, I can't answer that question except to say that we have no definitive plans to provide that functionality at this time.  We are aware that many users want this functionality, however.  It's on our radar. ... View more

Hi Natalie.  Let me try to address each of your problems individually below. Hierarchy Hierarchy is a way of speeding up lengthy, long-distance route calculations by ignoring small local roads and preferring highways.  It is not fully guaranteed to give the true shortest path, but it does a good job most of the time.  If you solve without hierarchy, all the roads will be searched until the true shortest path is found.  Consequently, your observation that some of the routes created were obviously not the shortest path when you were not using hierarchy makes me think that your network has some connectivity problems.  If you're not using hierarchy, the Closest Facility solver will always return the shortest path through the network.  If the shortest path looks wrong, it's probably because the network has some problems. Network dataset problems Here are a few common network dataset problems that cause incorrect results: - Your impedance attribute isn't set up correctly, so all roads have 0 impedance (then it doesn't even matter what roads are used in the route because it costs nothing to travel across any of them). - Your road features don't actually touch at intersection points.  Maybe when they were digitized, you didn't have snapping turned on, and the road endpoints just don't coincide, so it's not possible to travel across intersections. - Your road features touch, but the points of intersection don't have a vertex (if you have an Any Vertex connectivity policy) or an endpoint (if you have an End Point connectivity policy).  In this case, the roads appear connected but aren't actually logically connected in the network. This documentation page provides further information: ArcGIS Help (10.2, 10.2.1, and 10.2.2) Solve not creating a path to all facilities You definitely need to set "Facilities to Find" equal to the number of facilities you have if you want a route to be generated to all of them for each Incident.  If some routes still aren't being generated, it's possible that no route was found in the network (which should generate a warning message).  That would be another symptom of a network dataset problem. Other things to think about - If you're having trouble with your network dataset, and if you don't need to use your own street data (for instance, you have your own forest roads that you've added), you could use our online Closest Facility service.  You would be charged credits from your ArcGIS Online account, but it would save you the trouble of creating and managing your own network dataset.  You can connect to the online services through ArcMap as described here: ArcGIS Help (10.2, 10.2.1, and 10.2.2) - If you just need the travel time or distance between your points and not the actual routes taken, you should use the OD Cost Matrix tool instead of Closest Facility.  It will run much faster, and it defaults to finding all OD pairs. ... View more

The Build Network tool is the final step in network dataset editing or creation.  After you've edited the source features or updated the network dataset properties (which has to be done manually), you have to run the Build Network tool in order for those changes to really take effect in the network. So no, this tool doesn't do everything you want to do, but you will still need this tool as the final step in your procedure. ... View more

Oh, I see.  Yes, you can use python for every step except the network dataset creation and network dataset property editing.   I don't know what you mean by "Can I use Python to set up a GP Tool Model to set the simulation up".  It's also not possible to alter network dataset properties in Model Builder.  You could possibly use ArcObjects to do that, and then you could call your ArcObjects executable code from within a python script. If the only thing that's changing are the street features referenced by the network dataset, you might be able to automate the whole thing.  Before starting your simulations, you could create your network dataset and get all the attributes and other properties defined.  Then, during each run of your simulation, if you edit the street features, you can just run the Build tool on the network dataset so that it incorporates the new edits.  If, on the other hand, you actually need to edit the network's attributes or connectivity properties or something, you will not be able to automate that with python. Have you created a network dataset before?  If not, I think it might be best if you run through the network dataset creation tutorial (ArcGIS Help (10.2, 10.2.1, and 10.2.2) ) first before you continue planning your simulation.  This will give you some idea of what's involved and put some of my suggestions above into context. ... View more