Latest Contributions by MelindaMorang

Are you trying to use the same tutorial and tutorial data on both your 9.3 machine and your 10.1 machine?  I wouldn't expect that to work.  Various improvements to network datasets have been made throughout the years, so the procedures and data used for the 10.1 tutorial might not work in 9.3. The 9.3 version of the tutorial is here: http://webhelp.esri.com/ArcGISdesktop/9.3/index.cfm?TopicName=Tutorials ArcGIS 9.3 is very old software.  You should upgrade if possible. ... View more

Is there some reason that barriers won't work for this application?  Barriers are point, line, or polygon features that can be added to the analysis in order to simulate impassible roads due to accidents, construction, floods, etc.  They do not modify the underlying network but simply affect the results of an individual analysis.  The barrier features can be edited prior to the analysis. http://resources.arcgis.com/en/help/main/10.2/index.html#/Barriers/004700000056000000/ ... View more

When you create a network dataset, it automatically creates a point feature class containing system junctions indicating the locations where edges in the network connect.  Did you, by any chance, delete the junctions feature class intentionally or by accident?  Otherwise, as Joe suggested, it might be some kind of error reading or writing to the geodatabase.  Have you tried doing the tutorial more than once, and did you get the same error each time? ... View more

You can set up an impedance attribute on your network, and you can calculate that impedance differently for each input feature class (roads, rails, etc.).  To do this, you need to understand how network attributes and evaluators work: About network attributes: http://resources.arcgis.com/en/help/main/10.2/index.html#/Understanding_network_attributes/00470000000m000000/ About evaluators: http://resources.arcgis.com/en/help/main/10.2/index.html#//00470000000n000000 ... View more

The best way to do this is to use the Copy Traversed Source Features tool.  It will create a feature class of the network edges that were used to create your closest facility routes, and you can export the names from that. ... View more

The best thing for you to do is to start with our Network Analyst tutorials, available here: http://resources.arcgis.com/en/help/main/10.2/index.html#//00470000005r000000 ... View more

Here are a few ideas: 1) Create a rail-only restriction and a road-only restriction on your network.  If you know in advance where your input points are located (on the roads, on the rails, or on both), you can turn on or off the appropriate restrictions before running the analysis. 2) On the features that connect the rail lines with the road lines, invoke a large impedance penalty to discourage transitions between the two.  This way, it's very likely that two points on roads will use only roads for the route, two points on rails will use only rails to connect, but a point on the road and another point on the rail will be forced to make a transition somewhere even though it's penalized. ... View more

Hi!  If you have an MXD with several layer files saved in it already, you can access those layer files and put them into a list as follows: #Get a list of all the layers in the map document mxd = arcpy.mapping.MapDocument(mxd_path) lyrs = arcpy.mapping.ListLayers(mxd) #Filter the list to obtain only the network analyst layers na_layers = [lyr for lyr in lyrs if lyr.isNetworkAnalystLayer] You can then iterate through this list when generating directions. If you're doing this from the python window in ArcMap instead of a standalone script, replace mxd_path in the script above with "CURRENT". ... View more

Can you post a screenshot of the evaluators for your cost attribute?  It sounds like you've either converted units incorrectly, or else some of your network edges have 0 impedance. ... View more

Hi Fiona.  Can you give us more details?  What type of network analysis are you doing (Route, Service Area, etc)?  Did you create the network dataset yourself?  Is it a file geodatabase network, shapefile, SDE, etc?  Can you post a screenshot of the error message?  All of these things will help us figure it out. ... View more

Yes, you can do this!  After you create your Route layer, open the layer properties, go to the Analysis Settings tab, and check true the Reorder Stops to Find Optimal Route option.  By default, the Route uses the input order of the stops as the order, but by checking this option true, you can have it rearrange the order to find the most efficient route, which sounds like what you want. See http://resources.arcgis.com/en/help/main/10.2/index.html#//004700000045000000 for more information. ... View more

In your Closest Facility Layer properties, go to the Network Locations tab.  In the section on the bottom called Finding Network Locations, you can choose which of your source features can have points located on them by using the check boxes.  You'll want to configure these settings the way you want them before you load your incidents and facilities.  See http://resources.arcgis.com/en/help/main/10.2/index.html#/What_are_network_analysis_objects/00470000003n000000/GUID-9722833A-C61D-4E66-87CD-796A8A7231A1/ for more information about network locations and how to use the settings I mentioned. ... View more

Hi Chase. If you have your own sidewalk data, you will probably want to use it to create a network dataset.  A network dataset is required as input for all the Network Analyst tool, and it contains the street (or sidewalk) network as well as properties that determine the travel time or distance across each network edge.  After creating your network dataset, you will probably want to use the Closest Facility tool to find the bus stop closest to each housing project and the travel time between them. To help you get started, I recommend working through some of the Network Analyst tutorials here: http://resources.arcgis.com/en/help/main/10.2/index.html#//00470000005r000000.  Exercises 1 and 4 are probably the most relevant. If you have GTFS public transit data (the kind used in Google Maps), you can actually do a slightly more nuanced analysis using the BetterBusBuffers tool, which you can download from ArcGIS Online here: http://www.arcgis.com/home/item.html?id=42e57c5ff9a0497f831f4fced087b9b0.  This tool can count the number of transit trips available at a set of point (your housing projects) during a time window.  So, instead of just measuring the distance to the closest stop, it can actually count how many buses use that stop, which gives you a more complete picture of how much transit access the housing project residents have. ... View more

So each block group has an extra travel time associated with it?  If so, that will be hard to incorporate into a Service Area analysis around the Facilities, since these service areas will have no relationship to the block groups at all.  Can you, instead, generate the service areas around the block groups?  If so, you can use the Attr_[Impedance] field in the Service Area Facilities sublayer to add a customized delay time to each block group.  When you load the block groups as SA Facilities, use field mapping to map your delay time field in block groups to the Attr_[Impedance] field in SA Facilities, where [Impedance] signifies the travel time cost attribute on your network.  Read more about the Attr_[Impedance] property under Facility properties on this page: http://resources.arcgis.com/en/help/main/10.2/index.html#/Service_area_analysis/004700000048000000/ If creating service areas around the block groups isn't what you want, can you explain better how you want to incorporate your calculated extra time from the block groups into the service areas for the facilities?  Do you want to add extra travel time to the roads near each block group? ... View more