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6

As far as I know it's not possible to solve for alternate routes without some additional input or change to the analysis. In a network, given a particular impedance, there is only one shortest route between two points. As soon as you start looking for alternates without any additional input you've essentially removed the 'shortest' constraint and are back to ...


3

ST_StartPoint() only accepts LineString as input. You'll have to strip your table down from MultiLineString to LineString, either by taking only the first element up each geometry ALTER TABLE foo ALTER COLUMN geom TYPE Geometry(LineString,4326) USING ST_GeometryN(geom,1) Or, more correctly, dumping the multis out, in case there are legit multis. ...


3

At the moment, I could only easily find data for the UK: http://data.dft.gov.uk/gb-traffic-matrix/Raw_count_data_major_roads.zip It's in .csv format so you can manipulate it in Excel or by using other softwares (much easier than pdf's!). It also contains coordinates to immediately import the points into GIS software (tested this successfully with QGIS). ...


3

It may seem like laziness on the part of Watershed tool developers to stick with the simplest and oldest flow algorithm, D8, but there is a very sound reason for doing so. The difference between the D8/Rho8 flow algorithm and the more advanced algorithms that you mention (e.g. D-infinity) is mainly in their inability to represent the dispersion of overland ...


3

Yes, you can do this with pgRouting. As a starting point I would recommend you to look at the pgRouting Workshop. Most efficient for your case might be the one-to-many shortest path funtion named kDijkstra. You could import your node-pairs into a PostgreSQL database or just write a small application that reads the CSV file and then runs the SQL queries. ...


2

I believe the software you are looking for is called "BP Distance Tables". It is a very easy to use program that does not require you to enter all the waypoints. You simply enter the starting and ending ports and in some cases you select the preferred route. The program does the rest. It is used by many ships to roughly plan their route. It gives them ...


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osrm-isochrone is a small node.js library for generating drivetimes.


2

You could calculate a buffer (not more than 5 meters) for the start- and endpoint of every linestring. Then, intersect the buffer with the road network. A line that doesn't intersect with the buffer is likely to be a "correct" unconnected road. However, you'll have to play with the buffer radius for satisfactory results.


2

GraphHopper (using OpenStreetMap Data) GraphHopper offers memory efficient algorithms in Java for routing on graphs. E.g. Dijkstra and A* but also optimized road routing algorithms like Contraction Hierarchies. It stands under the Apache License and is build on a large test suite. OpenStreetMap is directly supported from GraphHopper. Without ...


2

What you are looking for is called 'reverse geocoding' and is implemented e.g. with Nominatim API


2

Have you done the pgRouting workshop? The workshop should clarify the following: There are import tools for OSM data, so the network will contain the routing topology already after import. If you still want to use SHP files, then it explains how. Your bus stops have coordinates, so you just need to start from the nearest point in your road network. ...


2

Works for me in QGIS 2.6 with Processing 2.6 (on Win7) and the test data Spatialite file from the repository. If you are using different data, please share it. Check if network and points are in the same CRS.


2

What you should look for is called 'Map Matching'. I've opened sourced my idea based on GraphHopper very recently here so it is still in a VERY early shape, please give feedback via providing data or creating issues etc.


2

You can use the pgRouting function pgr_nodeNetwork, which will create nodes at intersections of linestrings. So in your case it will split the linestring into two geometries. But there is a danger that intersections, that should not be connected (ie. over- or under-passes), will also get broken into two segments.


1

You can try jsprit. If you determine the time windows where both drivers meet each other at a specified location a priori, then it is easy to model (just look at the 'Simple Example' in the wiki to figure out how you model and solve such a problem). Time windows are defined as follows: ...


1

If you want a GUI for pgRouting, you can install the pgRoutingLayer plugin for QGIS. It provides a GUI to access pgRouting functions to compute routes. The routes can be displayed and exported to QGIS layers which you can manipulate and analyze any way you want. You can see the plugin in action in the following screenshot (panel on the right). The plugin ...


1

The way that I would try to answer your original question is to add a field to your roads and update it with a count of vertices. Add a Long Integer field Calculate that field using the Python parser to be equal to !shape.pointcount!, You can then use the vertex count field as, or to contribute to, your impedance field. You'll need to think about ...


1

If you have a well made road graph shape (with from and to nodes), you can use my qgis processing scripts at https://github.com/chourmo/QGIS-Transit-tools For batch starting points, use Shortest-times car If you want to find times from start to end, make a lines files and use Shortest-path car


1

You can find multiple versions of routing scripts which use the QGIS network analysis library in my Github repository, e.g. https://github.com/anitagraser/QGIS-Processing-tools/blob/master/2.2/scripts/point_layer_to_route.py which converts an ordered set of points into a route. None of the scripts use the intersections of an input line with the network. ...


1

If you are into Java and want Flexibility, Graphhopper is an excellent alternative. Peter, the project lead, actively encourages extensions and changes and the community is very responsive. Graphhopper works differently to Pgrouting (I use both) and it is extremely fast. Instead of using a PostGis database, Graphhopper builds its graphs direct form the .pbf ...


1

Since you appear to use a vector representation of the routes, you may first split it into short segments (in order to later have a representative view on slope etc), using v.split; then add a new column to the attribute table of that road map: "slope double precision" using v.db.addcolumn; eventually upload the respective road segment slopes to the ...


1

Have you followed the guidelines on these pages? http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//004700000057000000 http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//004700000020000000 "Using hierarchy by default As long as the network dataset has a hierarchy attribute, you can set any network analysis layer you create to use ...


1

@Adrian, I am really unfamiliar with the pgrouting results, however the documentation is very detailed. My answer is based on a two-step function, which will be very inneficient in SQL but [likely] produces the results. This [untested] solution will NOT optimize which is the best starting point, but will reduce the entire route network to only the edges ...


1

I have found it, it is worth having a look because I think there are not many safe route planners based on past accidents events http://opt.berkeley.edu


1

Based on a quick Google search, I believe what you're looking for is http://www.ridethecity.com It defaults to New York, but you can select from a number of major cities in the United States, Canada, France, Spain, Australia, and a couple of others. Very interesting application! And apparently (according to this question) it's driven by PgRouting.


1

You could try my routing script for QGIS Processing based on the core network analysis library. It expects a point layer and a network layer as input and returns a route between the points.:


1

What you want to do is possible, but not in the manner you're thinking. A network could generally be considered static in that the rules and restrictions for the edges are governed by single, static values. Accounting for change and time of day is another level known as Traffic. You may want to read through this ArcGIS help page for a detailed explanation, ...


1

In JOSM you can use the PicLayer plugin an load your raster image in and digitise the data into vector indoorOSM format. I will not be a 5 minute process you will have to plan a few hours into create the JOSM project and digitising will the time consuming part. http://wiki.openstreetmap.org/wiki/IndoorOSM#PicLayer JOSM is downloaded from ...


1

A possible solution could be: Modern maps show 30 or 50 km/h for situations with/without traffic. The classic map show 40 km/h as a way of representing both situations as a single number.


1

In my opinion trouble is that st_makeline function is making line from set of edges that have different directions. I'm using function ST_Union to join edges and don't have this problem. Maybe you should use this function insted.



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