As for what I want to do: The three coverages are of tracts, roads, and
journey to work data. What I want to do is display the road network
with different colors for each class of roadway (an attribute attached
to each road segment) and show the number of workers from any tract
traveling to any of a set of tracts somewhere else in the region.
To create ps map with line width based on number of travelers you can use
ps.map.new :
# blue color stripe
vector road.6-9
cwidth 0.001 # 1 point ~ 1000 in category
ref left # justification => direction from start to end of line
color blue
label Number of workers (1pnt~1000 workers) # legend label
lpos 1
end
# black outline
vector road.6-9
coffset 0.001
color black
width 1
lpos 1
end
See ps.map.new man.
Radim