STAR-APIC Mercator MCF Reader/Writer

Note: MERCATOR, formerly developed by Esko-Graphics, is now part of STAR-APIC

The Mercator MCF Reader/Writer module provides FME with access to the Mercator MCF format.


The Mercator MCF format is a collection of different types of data which include lines, areas, points, text, externals, and jobs. Each type of data is stored in a separate file, often with all the files of a particular dataset residing in the same folder. The files are stored in DTO format, have the extension .dto and are named <dataset name>_<file type identifier>.dto. The file type identifier is “l” for lines, “a” for areas, “p” for points, “e” for externals, “t” for text, and “j” for jobs.

FME considers a Mercator MCF dataset to be a set of files in the same folder with the same dataset name. The FME is able to determine the type of data by the <file type identifier>.

Reader Overview

The MCF reader produces FME features for all feature data held in files that reside in a particular folder. For each file, the reader checks to see if that file is requested by looking at the list of IDs specified in the mapping file. If a match is made or no IDs were specified in the mapping file, then that file is opened to be read. The MCF reader extracts features one at a time and passes them on to the rest of the FME for further processing. When the file is exhausted, the MCF reader starts on the next file. When all MCF files in the folder have been read, then the reader is closed.

MCF uses an upper-left origin for its coordinates and FME uses a bottom-left origin. To compensate for this, all y values are multiplied by -1 to “flip” them over the x-axis.