|USGS Digital Line Graph
USGS DLG (Digital Line Graphs) are supported for reading and writing by the GDB Library. The full topology of a DLG file is not retained during a read operation. Any Area information present in a DLG file will not be retained. In addition, only the first attribute code of a line will be retained, all others will be skipped.
DLG files written out by this program are equivalent to DLG level 2 files. When DLG files are written out, a node list is generated, and node-to-line as well as line-to-node linkages are generated. Since the full topology of the file is not retained, the left and right area fields of a Line Record will be initialized with a -1.
USGS DLG files may be created by Works programs. The DLGREAD and DLGWRIT programs may also be used to import and export DLG format vector data.
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