As it was mentioned in chapter 65 “Import of spatial data in SHP format”, SHP file is a binary file of a special format which contains data about features of some spatial category (“shapes”). Besides, a record of attributive data stored in the file with DBF extension can be linked with every shape. Thus when exporting features of some definite type to SHP file it is also possible to export to DBF file attributive data stored in one of the tables linked with features of the present type.
Among spatial categories of ObjectLand features only the following three categories have similar shape types in SHP format and can be exported to this format:
Point features are exported as shapes of the type Point;
Line features are exported as shapes of the type PolyLine;
Area features are exported as shapes of the type Polygon.
Since every SHP file can contain shapes of one type only and there is no analogue to the notion of ObjectLand feature type, when exporting a map an individual SHP file is created for every feature type being exported. Names of files differ in one or several digits added to them.
For every SHP file being created two more files are always generated with the same name but with different extensions. The file with DBF extension contains records of attributive data from the table linked with feature type being exported. If no linked table is indicated for feature type in export settings, records of the corresponding DBF file will consist of a single field ObjectID containing internal numbers of features.
An index file with SHX extension contains offset of description of each shape from the beginning of the SHP file with the same name.
Detailed description of format of SHP files is given in manuals on software products of ESRI, Inc.
 |  |
