Hello Sumo - Introduction
This tutorial aims at first time Sumo users. We are building the simplest net possible and let a single car drive on it. All files mentioned here can also be found in the <SUMO_HOME>/docs/tutorial/hello directory. The most recent version can be found in the repository at <SUMO_HOME>/tests/complex/tutorial/hello/data/.
In SUMO a street network consists of nodes (junctions) and edges (streets connecting the junctions). Thus, if we want to create a network with two streets, subsequent to each other, we need three nodes and two edges. We will see in the section on #Routes, why the simplest network cannot contain only one edge.
All nodes have a location (x- and y-coordinate, describing distance to the origin in meters) and an id for future reference. Thus our simple node file looks as follows
<nodes> <node id="1" x="-250.0" y="0.0" /> <node id="2" x="+250.0" y="0.0" /> <node id="3" x="+251.0" y="0.0" /> </nodes>
You can edit a file with a text editor of your choice and save this for instance as hello.nod.xml where .nod.xml is the default suffix for Sumo node files.
Now we are connecting the nodes with edges. This is as easy as it sounds. We have a source node id, a target node id, and an edge id for future reference. Edges are directed, thus every vehicle travelling this edge will start at the node given in from and end at the node given in to.
<edges> <edge from="1" id="1to2" to="2" /> <edge from="2" id="out" to="3" /> </edges>
Save this data into a file called hello.edg.xml. Now that we have nodes and edges we can call the first SUMO tool to create a network. Make sure NETCONVERT is somewhere in your PATH and call
netconvert --node-files=hello.nod.xml --edge-files=hello.edg.xml --output-file=hello.net.xml
This will generate our network called hello.net.xml.
Now that we have a net, we still need a car. In SUMO the vehicles have types defining their basic properties such as length, acceleration and deceleration, and maximum speed. Furthermore it needs a so called sigma parameter which introduces some random behavior and is due to the car following model used. Setting it to 0 gives a deterministic car.
Now we define a route for our car which simply consists of the two edges we defined.
Last but not least we define our single car mainly referring to the entries before and giving it a departure time as in the following hello.rou.xml file. There are many more attributes for customizing a vehicle and its type. See "Definition of Vehicles, Vehicle Types, and Routes" for further information.
<routes> <vType accel="1.0" decel="5.0" id="Car" length="2.0" maxSpeed="100.0" sigma="0.0" /> <route id="route0" edges="1to2 out"/> <vehicle depart="1" id="veh0" route="route0" type="Car" /> </routes>
Now we glue everything together into a configuration file
<configuration> <input> <net-file value="hello.net.xml"/> <route-files value="hello.rou.xml"/> </input> <time> <begin value="0"/> <end value="10000"/> </time> </configuration>
Saving this to hello.sumocfg we can start the simulation by either
sumo -c hello.sumocfg
or with GUI by
sumo-gui -c hello.sumocfg
When simulating with GUI it's useful to add a gui-settings file, so you don't have to change the settings after starting the program. To do so, alter hello.sumocfg to look like this
<configuration> <input> <net-file value="hello.net.xml"/> <route-files value="hello.rou.xml"/> <gui-settings-file value="hello.settings.xml"/> </input> <time> <begin value="0"/> <end value="10000"/> </time> </configuration>
After that create a file with the viewsettings
<viewsettings> <viewport y="0" x="250" zoom="100"/> <delay value="100"/> </viewsettings>
Save this as the name you included in the config file, in this example this would be hello.settings.xml.
Here we used viewport to set the camera position and we used delay to set the delay between each step of the simulation in ms.
More information on defining networks using XML can be found here: Networks/Building Networks from own XML-descriptions. NETCONVERT also allows to import networks from other applications, further information is available here: Networks/Import.
More information on defining vehicles can be found here: Definition of Vehicles, Vehicle Types, and Routes.