&args cover   /* name of clean river coverage
&type 'Based on flipper, but doesn't flip
/* adds items and calculated jorder
&if [show program] ne 'ARC' &then; &do
   &type This must be started from ARC
   &return &pause 'Exiting.  Try again.'
&end

/* set up for processing
build %cover% line
build %cover% node
indexitem %cover%.aat TNODE#  /* This will speed things up
indexitem %cover%.aat FNODE# 
&if ^ [iteminfo %cover% -arc JORDER -exists] &then
  additem %cover%.aat %cover%.aat JORDER 4 4 i
&if ^ [iteminfo %cover% -arc SHREVE -exists] &then
  additem %cover%.aat %cover%.aat SHREVE 4 4 i
&if ^ [iteminfo %cover% -arc STRAHLER -exists] &then
  additem %cover%.aat %cover%.aat STRAHLER 2 2 i
&if ^ [iteminfo %cover% -arc TLENGTH  -exists] &then
  additem %cover%.aat %cover%.aat TLENGTH 4    12     F      3
relate add
down
%cover%.aat
INFO
TNODE#
FNODE#
linear
ro
~


/* calculate total length and order from mouth
ARCEDIT 
ec %cover%
ef node
&if ^ [iteminfo %cover% -NODE flag -exists] &then
  ADDITEM flag 2 2 c
ef arc
sel all  /* if you are not sure of unique IDs
calc %cover%-id = %cover%#
calc JORDER = 0
save
sel  DOWN//RIVERS-ID > 0
nsel /* these ar the outlets of a well-constructed system
calc JORDER = 1  /* we have river outlets
calc tlength = LENGTH
&s order 1  /* here we number the arcs from the outlet
&label beowulf 
  sel JORDER = %order%
  &s num  [show number select]
  &if %num% eq 0 &then; &goto done
  &s i = 1
  &label startloop1
    &s id%i% = [show  arc [show select %i%] item %cover%-id]
    &s length%i% = [show arc [show select %i%] item tlength]
    &s i = [calc %i% + 1]
  &if %i% le %num% &then; &goto startloop1
  &set order = [calc %order% + 1]
  &ty working on stream order %order% %length1%
  &s i = 1
  &label startloop2
    sel %cover%-id eq [value id%i%]
    sel connect
    resel JORDER = 0
    &if [show number select] > 0 &then ; &do
       calc JORDER = %order%
       calc tlength = [value length%i%] + LENGTH
    &end
    &s i = [calc %i% + 1]
  &if %i% le %num% &then; &goto startloop2
&goto beowulf
&label done
&set order = [calc %order% - 1]
&type The highest order is %order%   /* 32
QUIT
y
y

&RETURN