Northgate StruMap Reader/Writer

The StruMap® reader and writer modules enable FME to read and write Northgate Information Solutions StruMap SGF/SGX format files. StruMap SGF/SGX files use a published ASCII format.


The StruMap reader and writer support the storage of point, line, polygon, and text geometric data in a single file. The names of the user-defined attributes are not stored with each feature, but rather in the file header where the structure of the features are defined.

FME considers a StruMap dataset to be a single file.

Reader Overview

The StruMap reader extracts features from the input file individually and passes them on to the rest of the FME for further processing. An important thing to note in the StruMap input file is that text components or child can be attached to any geometric types, whereas line symbols can only be attached to lines. The StruMap reader will not output these as a single aggregate feature, but rather as a series of features sharing the same strumap_id. Additionally, a strumap_child_id is added to each child to identify its order.

Writer Overview

The StruMap writer creates and writes all features it is given to the file specified by the DATASET keyword. Any existing StruMap files in the folder that have the same name as the output dataset will be overwritten with the new data.

Multiple geometric types can be stored in each StruMap file. Any feature whose feature type is not specified in the mapping file will not be written to file. If no strumap_id is present, a feature is considered a single feature in the output file (as opposed to being part of an aggregate). Features that share the same ID, which pass through the writer one after another (grouped by ID prior to entering the writer), are considered a single feature when output to file. It is an additional requirement that components of a parent feature pass through the writer before their children. Otherwise, the parent and child relationship may not be realized.

The JOIN directive is not supported by the writer; in other words, features must carry all the attribution before they are passed into the writer.