Network Analysis Tool
Functional Module | Error Detection Criteria | Analysis Components |
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Based on ID | Connectivity |
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Duplicate |
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Missing |
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Based on Location | Connectivity |
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Duplicate |
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Missing |
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Invalid Geometry |
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Analysis Component | Error Detection Principle | |
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Based on ID | Based on Location | |
Connected Link Group | Identified based on the link ID, start node ID and end node ID information in the attribute table in the link layer. Sets of inter-connected links (at least two or more) are listed in different groups. | Identified when discontinuity are found at the extreme vertices of the link in the network. The tool checks the spatial connectivity on the basis of user specified tolerance value. If found, then the sets of inter-connected links (at least two or more) are listed in different groups. |
Orphan Link | If the start node and the end node IDs of a single link are not found as connected with any other link IDs in the attribute table of the link layer, then the link is detected as the Orphan Link. | Detected if a single link feature does not have the edge of another link at upstream or downstream within the user specified tolerance value in map. |
Orphan Node | Detected if a node ID in the attribute table of node layer is not found in either of the start node ID or end node ID field of the attribute table of the link layer. | If a node feature has no edges of any link feature within its buffer distance specified by the tolerance value then its identified as an orphan node in map. |
Duplicate Node | If same node ID value is found more than once in the attribute table of the node layer then the nodes with same ID are detected as the duplicate nodes. | If two or more nodes are found at the same location within the buffer distance, then they are detected as the duplicate nodes. |
Duplicate Link | If same link ID value is found more than once in the attribute table of the link layer then the links with the same ID are detected as the duplicate links. | If two or more links are overlaid at same position and with same alignment within the buffer distance, then they are detected as the duplicate links. |
Missing Node | If a node ID (in the start node or end node field) in the attribute table of the link layer is not present in the node ID field of the node layer, then these IDs in the link layer are identified as the missing nodes. The links with the missing node IDs are sorted under this category. | If no node object is found at one or both edges of a link within the tolerance value, then the link object is detected as with the missing nodes in map. |
Invalid Node | N/A | If a node has attribute information but the corresponding object is missing in the node layer in map then its detected as the invalid node. |
Invalid Link | N/A | If a node has attribute information but the corresponding object is missing in the node layer in map then its detected as the invalid node. |
- Clicking on the () button detects the interconnected links (at least two or more) and lists them in groups in the display panel. The panel is split into two segments. The left portion shows the interconnected link groups and the right portion shows the FID of the interconnected links (in the link layer) of each group. Similarly, the (
) and (
) buttons investigate the existence of the orphan links and orphan nodes in their respective layers. If found, the display panel shows the FIDs of such objects by default, the first item in the display panel is always selected in the list and highlighted on the map.
- Clicking on the () and (
) buttons detects the duplicate nodes and links in their respective feature layers. The display panel shows the duplicate groups in the left portion and the FIDs of the duplicate items under each group in the right portion.
- Clicking on the () button finds the links that have no information or missing node information in the link layer. The display panel shows the FIDs of the affected links and the positions of the missing nodes (e.g. start or end) in a table. Note that in the Based-on Location module, the tool considers the direction of digitizing a link in defining its start and end nodes.
- Clicking on the () button detects the invalid or erroneous link and node objects in their respective layers. The display panel shows the FIDs of the invalid links and nodes if found.
