TerrainAccessOperator.MaxDistance Property
Gets or sets an attribute variable giving the longest interesting distance from a starting feature, in meters.
Syntax
public AttributeVariable< System.Double > MaxDistance { get; set; }Property Value
Default: 10000.0
The longest interesting distance from a starting feature, in meters.
Remarks
The analysis will take place inside a rectangle whose size is determined from an effective max distance, defined as
effective max distance = min(MaxDistance, MaxTravelTime * v)
where v is the maximal vehicle speed expressed in meters per second. In other words, if MaxDistance is short and MaxTravelTime is long, the effective max distance will just be the explicit MaxDistance. But if the MaxDistance is long and MaxTravelTime is short, then the effective max distance will be the short MaxTravelTime multiplied with the maximal vehicle speed, since it would be impossible to get farther away without exceeding the max travel time.
If the starting feature is a point, the analysis rectangle will be a square centered on this point, with a side that is twice the effective max distance.
If the starting feature is a line, the effective max distance will be used as an extra margin around the bounding rectangle of the line.
If the analysis starts from the entire road network, the effective max distance will be used as an extra margin around the requested area. The requested area will usually be a tile in a TileLayer, but it could also be the entire View.Area if a TileLayer is not used, or it could be a request area specified for a call to GetFeatures.
A shorter MaxDistance gives a smaller analysis rectangle which should improve the performance, but some calculated travel times can then become overestimates, since it is possible that a detour outside the small analysis rectangle could have improved some travel times. Note that there will be an output polygon from the operator with attributes that can tell whether this can have occurred; see the subsection "Accessibility from a starting point" in the main page for the operator class.
The property can be a constant, or it can be an attribute variable that is evaluated from the attributes of the feature, if any, from PositionInput as well as the View.UpdateAttributes.
Platforms
Windows, Linux, Android