• Geo-Coordinates
Geo-Coordinates

Geo-Referenced Networks#

SUMO networks are always encoded in Cartesian coordinates (meters) and may contain geo-referencing information to allow conversion to lon,lat. By default the Cartesian coordinates use the UTM-projection with the origin shifted to so that the lower left corner of the network is at 0,0.

Note

the projection information is encoded in the <location>-element at the top of the .net.xml file.

  • When importing a network from OSM, geo-referencing is automatically included in the generated .net.xml file
  • When importing a network from plain-xml files, coordinates may be given in lon,lat and importing using a projection option such as --proj.utm
  • When importing a network from Shapefile, the availability of geo-referencing depends on the format of the source data.

osmWebWizard with aerial/satellite imagery#

The de-facto standard for projecting background image layers on the internet is the Web Mercator Projection. When activating the Satellite background setting in osmWebWizard.py, the default projection is changed from UTM to Web-Mercator (proj string +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs) to avoid a projection mismatch between the network and the downloaded image layer. Note, that the coordinate origin (0,0) will still be shifted to the lower left network corner.

Checking Geo-Coordinates#

In sumo-gui and netedit when right-clicking anywhere in a geo-referenced network, the option copy cursor geo-position to clipboard is available. The resulting lat,lon coordinates are suitable for pasting into any map engine such as [maps.google.com] or [maps.bing.com]. Also, the network coordinates as well as the geo-coordinates at the cursor position are shown in the bottom right-corner of the window.

Performing coordinate-transformations#

  • using TraCI, coordinates can be transformed between network-coordinates (m,m) and geo-coordinates (lon,lat) and vice versa
  • using sumolib , coordinates can be transformed between network-coordinates (m,m) and geo-coordinates (lon,lat) and vice versa. Converting back and forth between lon,lat and raw UTM (m,m) is also supported.

Using geo-coordinates in XML-inputs#

The duarouter application supports attributes fromLonLat, toLonLat, viaLonLat to map trips directly onto the closest network edge or junction for the given coordinates.

Obtaining output with geo-coordinates#

  • A network can be exported as plain-xml in geo-coordinates using the netconvert command
netconvert --sumo-net-file myNet.net.xml --plain-output-prefix plain --proj.plain-geo
  • FCD-output can be obtained in geo-coordinates by adding the option --fcd-output.geo
  • duarouter supports option --write-trips.geo to create trip definitions with geo-coordinates (see above)

Mapping geo-coordinates#

It is often desirable to convert between geo-coordinates (lon,lat) and road coordinates (laneID, offset). This is typically accomplished in a 2-step process of first converting lon,lat to x,y-network coordinates (in m) and the matching those coordinates to the closest lane. The following resources can be useful for this task: