Latest Contributions by MelindaMorang

I'm guessing that the problem is most likely one of the following: - In your python code, when you run arcpy.na.MakeODCostMatrixLayer(), you aren't feeding it exactly the same parameters as the layer you have in ArcMap (where many of the parameters are set to defaults).  So maybe you have a different impedance attribute, or some restrictions are toggled differently. - When you add your origins and destinations, maybe the field mapping isn't working the same as it is in ArcMap.  In ArcMap, it's super easy to use the field mapping control on the Load Locations dialog.  In python, you need to use either a correctly formatted text string or an arcpy.na.NAClassFieldMappings() object. I know you can't upload your data, but can you upload a snippet of your python code?  Otherwise, it's virtually impossible to diagnose this problem. ... View more

Hmm, I don't know why things would have changed with an upgrade to 10.3, and it sounds like this issue might be a bit complicated and not resolvable on GeoNet.  I think you would do well to call Tech Support for this issue.  They can look at your data in detail and see if they can identify what's happening. Esri Support ... View more

By the way, from the behavior you are describing with restrictions not being obeyed, it sounds like your network attributes (particularly the restriction attributes) might be set up incorrectly.  Perhaps before deciding for good to use barriers, you should check your attributes to make sure they are correct, in case, even with the barriers, the results might be wrong. If you can further describe the issue you're having and give some details about your restriction attribute, I can try to help you debug the problem. ... View more

It's in the field mapping part (labeled as Location Analysis Properties below).  Did you scroll all the way to the bottom of this window? ... View more

You can download this package of tools from ArcGIS Online to create a network dataset that uses GTFS transit schedule data. http://www.arcgis.com/home/item.html?id=0fa52a75d9ba4abcad6b88bb6285fae1 The download includes instructions on how to set it up. However, you will have to have an editable street feature class that you can use as the basis for your network dataset.  You can obtain streets from your city, county, or metropolitan planning organization, OpenStreetMap, or from Esri's Streetmap Premium product (a newer file geodatabase version rather than the old SDC version you're using). ... View more

What about using census blocks instead of block groups? ... View more

Once the network has been created, you can add it to ArcMap and use the Network Identify tool (on the Network Analyst toolbar on the right side) to click on streets and see which other streets and junctions they are connected to.  The Network Identify window gives you a list of stuff the identified street is connected to, and you can click each one and have them flash in the map.  If roads that look like they should be connected don't show up in this list, then they aren't connected. However, I agree with Chris Donohue that it's better to fix these errors before creating your network dataset in the first place. ... View more

1. What tool or python methods are you using to programmatically create your line segments?  This is a bit outside my area of expertise, but I'm guessing there's some kind of environment settings for the tool you could put into place.  Or perhaps the Snap tool would help? ArcGIS Help (10.2, 10.2.1, and 10.2.2) If you describe your workflow a bit more thoroughly, I can try to help more. 2. Ah, interesting.  As you have discovered, you can't delete the feature class.  You could, however, delete all the features in the feature class (use Delete Rows or an update cursor) and then add the new features to the existing feature class.  Again, this might depend on how you're creating the features. ... View more

You can just set the U-Turn policy of your Network Analysis layer to "Not Allowed".  This is an NA layer setting rather than something you build into your network dataset. U-turn policies—Help | ArcGIS for Desktop ... View more

(Thanks, Chris.) Hi Charlotte J.  The previous answers have summarized the likely problem.  For some reason, your points are being located on network edges that are non-traversable.  Edges are non-traversable either because they are restricted because of a restriction, a barrier, or a negative impedance value (which the solver interprets as inaccessible). Normally, the first thing I would suggest you do is to check on the "Exclude restricted portions of the network" button in the NA layer properties "Network locations" page before you load locations.  This way, if an edge is restricted, the point won't get located there but will instead get located on the next-closest non-restricted edge.  This works great for restrictions and for existing barriers.  I'm not sure how you've constructed your 0mph edges, so I'm not sure if Add Locations will be able to determine that these edges are restricted or if it doesn't become apparent until solve time.  At any rate, this is the first thing I would try. To make your network a little more robust, I would create a restriction attribute that you can assign to all the non-car-traversable edges (like your bridlepaths) rather than using 0mph speed profiles.  That seems like a kind of odd way to do it when restriction attributes are specifically designed to do exactly this. Note for everyone: "Snap to network" does not impact whether or not points get "located" on the network".  No matter how you set this, the points are always "located" on a particular network edge (or junction), and that network location will be used as the starting point for the analysis.  "Snap to network" just moves the visible location of the facility/stop/incident to the network location.  Otherwise, it will show up in the original location of the input, even though it's the network location that's being used in the analysis.  To summarize: "Snap to network" will not change anything in the way your analysis runs and will not fix any of the problems Charlotte J is experiencing here. ... View more

No, this isn't going to work.  When you add a location to an NA layer (for instance, you add your park centroid as a Facility in a Service Area layer), the location "locates" on the closest network edge.  Although the geographical location of the point remains the same (the center of the park), the network analysis uses the network location of the point when considering how to route to it.  So if you erase all the network edges inside the park, the centroid will snap to the closest remaining edge, and the service area will build out from there.  If the park is large and has many entrances, this will be pretty inaccurate.  It would be more accurate to place a point at every park entrance and calculate service areas around all these points. ... View more