In the past, many users have indicated their need for some kind of alphanumeric node information. In many applications (especially for transit networks, as well as applications on a regional or national scale) network nodes are identified more easily by a name than a number.
Starting release 3.0, a limited support for alphanumeric node labels will be available.
Node labels consist of up to 4 alphanumeric characters. They are optional; i.e. at data base creation time, the user is asked whether the data base should contain node labels or not. This saves space for those applications in which there is no need for node labels and at the same time assures compatibility with all existing EMME/2 data bases.
In a first step (release 3.0), the use of these node labels is restricted to the following operations:
The node labels may be specified after the user defined data in the
node data table (d211.in). They may also be manipulated in the
interactive network editor, module 2.12. The default label of a node
is defined to be the alphanumeric representation of the node number,
padded to 4 characters with leading zeroes.
The nodes on all network plots may optionally be annotated with node labels, i.e. replacing the usual node numbers. The default annotation -number or label- is selected by means of a new switch (switch number 17). There is also a new graphic command "l" that allows switching from node numbers to node labels. The following table shows the different actions of the "l" and "n" graphic commands, depending on the current node display:
| Nodes on current plot contain: | nothing | numbers | labels |
| Effect of graphic command "n": | numbers | nothing | numbers |
| Effect of graphic command "l": | labels | labels | nothing |
The link and node subset selection dialog allows new keywords to select
nodes (lab=) or links (labi= and labj=) using node labels. The wildcard
character "_" (underscore) can be used in the label following the keyword.
For example, the line "LAB=yy__" will select all nodes with a label
starting with "yy".
The node labels may optionally be used to define transit line itineraries in module 2.21 and 2.22. A node specifier is first tested for a valid node number; if none is found it is tested for an existing and unique node label.
If defined in the data base, the node labels can be included in the following
reports:
2.14 - "list nodes"
2.24 - "list transit line itineraries"
2.24 - "transit lines on base network"
6.11 - "auto times and volumes on links"
6.21 - "list transit line itineraries"
6.21 - "list transit volumes on base network"
In modules 2.24, 6.11 and 6.21, a new module parameter has been added that determines if the node labels are to be used in the reports or not.