Latest Contributions by MelindaMorang

Hello everyone.  I just wanted to let you know about a new prototype tool from Esri's Network Analyst team which allows you to add GTFS public transit data directly to a network dataset.  You can use this network dataset with the Network Analyst tools to run time-aware analyses that incorporate the transit schedules. You can download the toolset and instructions here: http://www.arcgis.com/home/item.html?id=0fa52a75d9ba4abcad6b88bb6285fae1 Please do not hesitate to contact me at [email protected] with questions or comments about this toolset. ... View more

Hello Tim.  I just wanted to let you know about a new prototype tool from Esri's Network Analyst team which allows you to add GTFS public transit data directly to a network dataset.  You can use this network dataset with the Network Analyst tools to run time-aware analyses that incorporate the transit schedules.  This might be helpful for your study. You can download the toolset and instructions here: http://www.arcgis.com/home/item.html?id=0fa52a75d9ba4abcad6b88bb6285fae1 Please do not hesitate to contact me at [email protected] with questions or comments about this toolset. ... View more

Hello Saren.  Were you ever able to complete your analysis?  It might be too late to be relevant now, but you might find this tool helpful for your study: http://www.arcgis.com/home/item.html?id=42e57c5ff9a0497f831f4fced087b9b0 This tool allows you to create buffers around your bus stops and weight them by the number of transit trips that actually serve the stops. ... View more

Hello everyone.  I just wanted to let you know about a new prototype tool from Esri's Network Analyst team which allows you to add GTFS public transit data directly to a network dataset.  You can use this network dataset with the Network Analyst tools to run time-aware analyses that incorporate the transit schedules. You can download the toolset and instructions here: http://www.arcgis.com/home/item.html?id=0fa52a75d9ba4abcad6b88bb6285fae1 Please do not hesitate to contact me at [email protected] with questions or comments about this toolset. ... View more

Do your input points actually have a geographic location on the map?  Because Points to Line should be able to do this. What is your actual analysis about?  I understand from your description the type of lines you want to create.  I'm just wondering why you are trying to create these lines.  There might be a better way to accomplish your end goal. ... View more

Can you tell me a little bit more about what you're trying to do?  What's the overall goal of this analysis?  Maybe we can find a better way to do it. ... View more

It sounds like you need the Points to Line tool: http://resources.arcgis.com/en/help/main/10.1/index.html#//00170000003s000000 It creates a line connecting the input points, and you can specify a line ID field from your input data, so you could make it produce a different line for each slope value. ... View more

Ack, sorry, I did some more experiments, and I now see that, in fact, you CAN do what I was suggesting.  You don't have to have a turn feature class with every turn digitized in to use a custom script evaluator for global turns.  It WILL work the way I originally suggested.  I think if you just fix your syntax, you should be good to go. In the mean time, I'll see what I can do about us getting some better documentation for this subject.  If I work here and can't figure it out, we clearly didn't do a very good job. ... View more

Hi Liam.  I'm afraid I was incorrect in my earlier post.  You can't actually use the default turn script evaluator effectively unless you have actual turn features drawn into your network.  If you are going to use this method, you will have to manually create all the turn features.  As you mentioned before, this would undoubtedly be quite laborious. As for why your code isn't working, it's a syntax problem.  In your if statements, you would need to use something like this: fromEdge.AttributeValueByName( "RoadClass" ) Also, you won't be able to just call "Economy" by itself.  That value is meaningless unless associated with a particular edge element.  As I mentioned before, you can't update the cost of the edge element itself based on the next edge in the route because the route doesn't know what the next edge is going to be.  The reason I suggested the turns is that turns are the only cost-associated element that has information about the edge elements it's connected to. So, unfortunately, this doesn't leave you with a lot of good options.  If you know ArcObjects, you could build your own custom evaluator, but this is not an easy process.  And, again, you can't use a custom evaluator to determine the cost of an edge based on the next edge in the route because the solver itself does not know what the next edge is going to be. I'm really sorry I don't have a better answer for you. ... View more

Okay, I think I've got it figured out. You want to create your own global turn script evaluator that will add a certain number of liters of fuel needed for each type of transition between road types (turn).  So, the fuel usage on the edges will stay the same as you have them now, but each transition between edges can add some value, based on the way you want to calculate it. First, when you create your network dataset, make sure you click the button that tells it you want to model global turns. Next, set up the global turn evaluator, as follows: - In the network dataset properties window, go to the Attributes tab. - For your fuel usage attribute, click Evaluators. - After the evaluators window pops up, go to the Default Values tab. - In the Type column next to Turn, click to get a drop-down menu where you can select "Script". - Click the Evaluator Properties button on the right (looks like a finger pointing at a piece of paper).  A dialog will appear where you can write a simple Python or VBScript that says how the solvers should calculate the fuel usage for turns in your network.  You should be able to use some if statements to give it a different value based on the road types of the fromEdge and toEdge. ... View more

Actually, I think you can use Global Turns for this.  Global Turns allow you to specify a different delay for turns between roads of different classes. http://resources.arcgis.com/en/help/main/10.1/index.html#//004700000030000000 ... View more

Hi Liam.  Unfortunately, the Network Analyst solvers don't have a way of assigning an added cost based on the previous edge traversed.  When the solver calculates the cost on an edge or junction, it doesn't know what the previous edge or junction was.  So you won't be able to do this automatically. You could potentially use a turn feature class to add your costs, but you would have to set up the turns manually for each intersection where you want the added cost. Can you describe more fully what you are trying to do?  What's the goal of this part of your project?  Maybe we can find a better way to do it so we can avoid this problem. ... View more

Thanks for the kind words, Jeremiah.  I'm glad to see that you were able to come up with a really nice solution for your project! We here at Esri are working to develop a much more advanced and useful set of tools for public transit analysis.  I am always interested in hearing from users working in this area to learn about their work, the types of analyses they want to perform, and the challenges they have with our current software.  Feel free to send me a private message if you want to talk further about public transit analyses.  You are also always welcome to contact me with complaints or suggestions about Network Analyst tools or documentation in general. Thanks, and good luck with your transit projects! ... View more