The map display shows data from two sources: the node database, and the network scanner results.
The node database is read from the HECnet node name database at MIM. The code extracts name, node address, owner's name, name of the node's location, and location latitude/longitude. This information is retrieved daily. If your node location information is missing or incorrect, please contact Johnny Billquist, the keeper of the HECnet node database.
The network scanner looks at every node mentioned in the node database plus every node it can see as reachable. From these, it collects information about nodes and circuits (connections between nodes).
The map display takes as input the node and adjacent-node information collected by the scanner and summarizes it in two steps. First, all the nodes are grouped by latitude/longitude. Each distinct spot on the map is given a marker associated with all the nodes at that location. Nodes without location information are assigned the placeholder coordinates 37° 18′ S, 12° 41′ W (the location of Inaccessible Island).
Each item (node or circuit) has a "health" which is similar to its up/down status.
| Health | Description |
|---|---|
| Up | Node or circuit is currently visible to the scanner as operational |
| Down | Node or circuit is not currently visible to the scanner, or it is seen in the scan but the reported status is "not operational" |
| Faded | Node or circuit has been "down" for more than two weeks, or node has never been seen as "up". |
Location markers and connection arcs summarize multiple nodes and circuits. The color used for these comes from the health of the node or circuit components that go into them.
| Color | Description |
|---|---|
| All nodes at this location, or all circuits on this path, are "up" |
| Some nodes at this location, or circuits on this path, are "down", but the majority are "up" | | More than half the nodes at this location, or circuits on this path, are "down" |
| All nodes at this location, or circuits on this path, are "faded". But if a path is "faded" for more than 180 days, it is not plotted on the map at all. |
All location markers have a popup (window that appears when you click the marker) which lists the nodes at that location, grouped by heath status (up in black, down in red, faded in gray italics). Exception: the default marker at Inaccessible Island omits gray nodes because there are too many. A location marker that isn't gray also has a tool tip (appears when you hover over the marker) which lists the up and down nodes only, not the faded ones.
Arcs also have popups, which list the individual circuits for this path by their end point node names/numbers.
More detail on the mapper system, including details of how it operates, can be found here.