Inference Rules - Node Parameters (Collection)

Missing data values can be inferred from existing data, allowing gaps in data to be filled with reasonable values.

Inference data is edited on the Inference Data Editor.

The following parameters can be inferred for nodes:

Parameter	Inferred from
Chamber Floor Depth	Values are inferred from Depth From Cover values of connected pipes. Node Chamber Floor Depth is inferred as the greatest value found from the following: US Depth From Cover of connected downstream pipes DS Depth From Cover of connected upstream pipes
Coordinates	Upstream and Downstream node positions and pipe lengths. See Coordinates section below for more details.
Ground Level	Node ground levels can be inferred for any node where these values are missing. There are three methods by which ground level can be inferred: Infer from Ground Model currently loaded on the GeoPlan. Infer from Ground Level of surrounding nodes within a specified Search Radius. (See Ground Level from Surroundings section below). Infer from Cover Level at the node. Ground Level will be set equal to the Cover Level at the node.
Cover Level	Values inferred from Ground Level at node. Cover Level will be set equal to Ground Level at the node.

Coordinates

Node coordinates can be inferred for any node where these values are missing. Values are inferred if both x and y coordinates are zero or blank.

No inference is carried out if just one of these values is blank or zero. No inference is carried out if the node is not connected to the network. For node coordinate inference to work efficiently and correctly, you should attempt to sort out any connectivity problems in advance.

Note:

Bear in mind when using this option that a location of (0, 0) may be perfectly valid depending on the coordinate system used for your model.

InfoAsset Manager attempts to infer node coordinates for nodes where both x and y coordinates are zero or blank as follows:

• Check for upstream and downstream nodes of known position, and try to apply one of the following inference methods in this order:
  • Both an upstream and a downstream node were found, and at least one of the located nodes is adjacent in the network to the current node with a known length of pipe connecting the nodes. Compute the bearing between the nodes of known position, and then compute the position of the unknown node based on this bearing and the pipe length. If both upstream and downstream nodes are adjacent, the downstream pipe length is used in the calculation by default.
  • Only an upstream node of known position was found, and is located adjacent to the current node and a known length of pipe connects the nodes. Continue searching upstream for another node of known position. If a second node is found compute the bearing, and compute the position of the current node as in method 1.
  • Only a downstream node of known position was found, and is located adjacent to the current node and a known length of pipe connects the nodes. Continue searching downstream for another node of known position. If a second node is found compute the bearing, and compute the position of the current node as in method 1.

Ground Level from Surroundings

Ground Levels are inferred from nodes with ground level values within a user defined Search Radius of the node with a missing ground level.

1. InfoAsset Manager searches for nodes within the Search Radius of the target node that have a ground level value (these are not necessarily connected to the target node).
2. The ground level of the target node is calculated as the average of the ground levels of nodes found in Step 1 weighted by the inverse square of distance from the target node.

Example The contribution from each node to the ground level of the target node is weighted by the inverse square function of distance from the boundary node. Weight decreases as distance from the target node increases, therefore ground level of nodes closer to the target node will contribute more to the calculated ground level. If a node within the search radius does not have a ground level, it will be ignored during the calculation process.