Dima Routing returns "EstimatedByDirectDistance": why?

[Bernd Welter]

Sometimes a DIMA calculation returns "estimatedByDirectDistance" for some relations though the involved waypoint coordinates are located in trivial areas (no critical truck attributes or pedestrian zones). Here's an example that explains some side effects - maybe some of you can benefit from this post.

The example is quite minimalistic (2² matrix) and I applied some manual SearchSpaceBounds.

Within the given rectangle there's no route found: to get from the area north of the Adria to the southern part of italy within the rectangle it would require a ferry - I've restricted the rect for this example to an area which does exclude the ferries near Dubrovnik

XDima2.CreateAndGetDistanceMatrixRequest:

Code: Select all

{
  "$type": "CreateAndGetDistanceMatrixRequest",
  "distanceMatrixOptions":{
    "geographicRestrictions":{
      "searchSpaceBounds":{
        "restrictionMode":"CUSTOM",
        "customBounds":{
          "minX" :15.0,          "maxX" :18.0,          "minY" : 39.0,          "maxY" : 50.0
        }       
      }
    }
  },
  "resultFields": {
    "distances": true,    "travelTimes": true,    "violated": true,    "estimatedByDirectDistance": true
  },
  "startLocations": [
    {
      "$type": "OffRoadRouteLocation",
      "offRoadCoordinate": {        "x": 15.334595,        "y": 47.170803      }
    },
    {
      "$type": "OffRoadRouteLocation",
      "offRoadCoordinate": {        "x": 17.174305,        "y": 40.877792      }
    }
  ]
}

The response is

Code: Select all

{
  "$type": "DistanceMatrixResponse",  "summary": {
    "numberOfStartLocations": 2,    "numberOfDestinationLocations": 2,
    "percentageOfDirectDistanceRelations": 50,     "routingType": "CONVENTIONAL"
  },
  "contents": {
    "$type": "DistanceMatrixContentsArrays",
    "distances": [
      0,      986731,      986731,      0
    ],
    "travelTimes": [
      0,      59203.852,      59203.852,      0
    ],
    "violated": [
      false,      false,      false,      false
    ],
    "estimatedByDirectDistance": [
      false,      true,      true,      false
    ]
  }
}

So as you can see the relations A:B and B:A are estimatedByDirectDistance.

To get rid of this there are several strategies:

• Enlarge the custom rectangle
• Add an additional waypoint in the desired area such as "near Milano" which would also have an impact on performance (but better to have a successful routing compared to no one).
• Switch to HPR which does not apply the rectangle limitation.

Sidenote:

• Routing means to consider many options at the same time, e.g. the example above would also occur with a larger rectangle if the usage of ferries is set to "forbidden".

[Bernd Welter]

By the way - this topic also may touch further restrictions such as

• com.ptvgroup.xserver.routingprofile.CombinedTransport: suchb as boatPenalty and railPenalty
• com.ptvgroup.xserver.routing.GeographicRestrictions such as allowedCountries or prohibitedCountries

Effectively those restrictions will be applied through super positioning...