As it was said in subsection “Setting components”, the number of MIF files created when performing export of a map or its component is equal to the total number of feature types being exported or to the number of tables exported with these types depending on selected method of distributing feature types between files.
In any case for every MIF file being created MID file with the same name will be also created which as a rule contains data from the table linked with feature types of this MIF file. The number of lines (records) of MID file will always be equal to the number of features described in MIF file, the line number of the record corresponds to a sequence number of feature description. More precise rules of correspondence between features and records can be formulated in the following way:
If there is a linked table record for the feature being exported to MIF file, fields of this record are exported to MID file.
If there is no linked record for this feature, a line consisting of field separators (an empty record) is written into MID file.
If the box Export feature types to one file is checked, features of all types are exported to one “main” MIF file (the one which name coincides with the name selected in the settings). One of the tables linked with types being exported is recorded into MID file with the same name. Other linked tables are exported to MID files, number consisting of one or several digits is added to the name of each file. MIF file with same name which contains description of table structure and an array of “empty” features “None” corresponds to each MID file. The number of records in every MID file is equal to the total number of features being exported, and the record number corresponds to the sequence number of this feature in the main MIF file with which the present record is linked.
If for some feature type exported to MIF file no linked table was specified in export settings, MID file is still created, however, its lines contain internal numbers (ISN) of features being exported. These numbers are usually inaccessible for the user working with ObjectLand, but they can be used by applications having access to internal structures of ObjectLand data.
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