Questions working with vector data

[Radim Blazek]

> 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