.\" @(#)M_dig_to_dlg	6.1.2.1	 4/29/93
.TH dig_to_dlg 1 GRASSmapdev
.SH "NAME"
dig_to_dlg \- convert digit file to dlg file
.br
.I (Map Development Tool)
.SH "SYNOPSIS"
.B dig_to_dlg
.SH "DESCRIPTION"
.I Dig_to_dlg,
is the second phase of
.I mapdev
and is an interactive program to convert a
.I digit
file into a
.I dlg
file using the US Geological Survey's DLG (Digital Line Graph) level 3 optional
format.
Deducing of topological information from a 
.I digit
file is a complex task and must be accomplished in a single session of
.I dig_to_dlg.
.sp
The conversion of areal features from a digitized map to dlg-3 format is
accomplished by the program leading the person through
each area and asking if it is acceptable.  The area is highlighted again if
it is also an island.
After an area is accepted the program assigns it an area number and goes on
to the next area until every possible area has been accepted.
Linear features are processed automatically by
.I dig_to_dlg
and no interaction is needed.
Any digitizing errors (unlinked areas, overdrawn or missing lines)
become apparent at this stage.
.sp
.I Dig_to_dlg
implicitly derives area numbers, node numbers, line numbers, and area numbers
to either side of lines as the session progresses.
.sp
Using the color monitor is
optional, but is required if the map is to be properly converted to DLG format.
When the color monitor is used, the map is displayed and
each area in turn is highlighted, and the person visually determines
if an area or island is acceptable.  If an area is not accepted
.I dig_to_dlg
highlights each line segment in turn asking if that particular line
segment is acceptable.
Color coding is as follows:
.sp
.nf
.cs R 36 4
--------------------------------------------------------
| GRAY line    | An area edge                           |
--------------------------------------------------------
| BLUE line    | A linear feature                       |
--------------------------------------------------------
| YELLOW line  | An area or area segment to be accepted |
--------------------------------------------------------
| RED line     | A questionable area segment            |
--------------------------------------------------------
.cs R
.fi
.sp
.I Dig_to_dlg
allows zooming in on any portion of the display to get a better view of the
digitized map.
.SH "SEE ALSO"
b_a_dlg(1), a_b_dlg(1), digit(1), dlgedit(1), dlg_to_cell(1)
.SH "AUTHOR"
Michael Higgins, U.S. Army Construction Engineering Research Laboratory
.br
James Westervelt, U.S. Army Construction Engineering Research Laboratory
