[GRASSLIST:3914] Re: TIGER/Line 2000 feature names?

[Hal Mueller]

At 8:13 PM -0500 6/19/02, Sean Billig wrote:
>this displays a small county map that looks to be a little distorted, is
>there a way to correct the natural distortion for a flat map within GRASS?

Distorted in what way?  Looks too wide?  If so, you're running into 
projection weaknesses.  Not errors, but just "features" of the 
projection you've chosen to use.  You're viewing lat-long data as X-Y 
positions, I suspect.  That means that the north-south scale is ok, 
but the east-west scale is too big, by a factor of cos(latitude). 
You'll need to reproject your lat-long data to a projection like 
transverse Mercator, or perhaps the State Plane Coordinate System for 
your state (which you didn't mention).

What is the projection of the final map you're producing?  What 
scale?  What is its intended use?

>When I query a line on the vector map, (d.what.vect) I get an output that
>reads:
>
>87:03W(E) 45:52:24N(N)
>neighbor_roads in PERMANENT  Line - Category 181946201 <not labeled>

Misleading error message.  There are two levels of labeling--a 
feature gets a category number, and then a category number gets a 
name.  Looks like the number-name association isn't getting imported 
from the Tiger file, although the feature-number association is.  I 
haven't worked with Tiger in Grass, so I can't say why this is 
happening.

----
Hal Mueller
Seattle, Washington    hal at seanet.com