GRLINK is the program which implements the link-to-grid conversion, i.e. it transforms a link data file into the corresponding grid data file. The following calling sequence is used:
grlink input-file grid-distance [output-file]
The parameter input-file specifies an existing link data file which is to be read and transformed into a grid data file. Usually, the link data file is created by GRMACRO, but files from other sources can be used as well, as long as the file is formatted according to the format specifications given in section 5.1. In particular, it is important to note that the link file can contain more than five data values per link, even if the files generated by GRMACRO are limited to a maximum of four values plus the total.
The parameter grid-distance specifies the grid distance, in network coordinate units, to be used for the conversion. By default, the same grid distance is used in horizontal and vertical direction, i.e. a square grid is assumed. However, it is also possible to define a rectangular grid by specifying the horizontal and vertical grid distances individually, separated by a slash (e.g. ``.5/.25'').
The resulting grid data file is written to the file specified in the output-file parameter. If this parameter is not specified, the output is sent to the standard output for UNIX, to the console device on MS-DOS. The format of the resulting grid data file is described in detail in section 5.2.
Note that, depending on the size of the network and the chosen grid distance, as well as the performance of the system used, running GRLINK might be quite time consuming.