DESIRE.avx (v.2)
   Desire Lines.  This will create a desire line shape file (some call
it a spider diagram) from the user's data contained in a source table.
Desire lines may reflect travel patterns or something similar.  They
are generally used to represent Origin and Destinations (O-D).

   The extension loads a Button to the View GUI.

   The user is given two methods for producing the desire lines:

   1)  Create from centroids of a base theme.  The input table must
have one Origin and one Destination field.  The data in those fields
should match a unique identifier of a theme (probably a polygon or
point) in the View.  The extension will match the O-D fields to that
identifier and make a line from the centroid of the Origin feature to
the controid of the Destination feature.

   2)  Create from Lat/Lon fields.  This method requires no base theme
to map from.  The input data should have four fields, a Lat-Origin,
Lon-Origin, Lat-Destination and Lon-Destination field, with values
representing the coordinate system you want to map to.  The fields do
not have to be named those names, though.  The extension will simply
map the X & Ys to make the desire lines.

   NOTE:  Since the first method is matching data to a base theme, it
can take a bit of time, especially if the basetheme is a large one.
The second method is much quicker.

   Both methods allow the user to pass fields of the input table into
the desire line's attribute table.  The attribute table will also have
a new field called DESIREID, which is a simple numeric ID field.  It
also will have a LENGTH field, containing the length of the desire
line, based in the view's coordinate system.  (If the view is in
Decimal Degrees, the user will be prompted for a unit system for the
LENGTH field.)

NOTE: THIS EXTENSION WAS DEVELOPED WITH DIALOG DESIGNER, THEREFORE TO
USE THIS EXTENSION USERS MUST HAVE THE AVDLOG.dll AND AVDLOG.dat FILES
INSTALLED TO THEIR SYSTEMS.  THESE ARE INCLUDED IN THIS ZIP FILE.
Copy each file to...
1) AVDLog.dll.  Copy this into *\BIN32 directory
2) AVDLog.dat.  Copy this into *\LIB32 directory

NOTE:  THIS EXTENSION WAS DEVELOPED IN ARCVIEW 3.0a, NOT 3.1, THEREFORE
I CANNOT GUARANTEE IT WILL WORK.  SORRY.

by Kevin O'Malley, 09/4/1998
KevOMalley@juno.com
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Portions of this work include intellectual property of Kevin O'Malley
and are used herein with permission. Copyright (C) 1998
Kevin O'Malley.  All rights reserved.
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