[GRASSLIST:4993] Re: US Census boundary file problem

[Radim Blazek]

On Monday 18 November 2002 10:44 pm, Michael Ash wrote:
> Using d.what.vect and moving due east from northern New
> Mexico, U.S.A., I find New Mexico, Nothing where Texas
> Should Be, and Oklahoma:
...
> I think that the problem is an unclosed area.

I was curious where the problem is and I found dangle on the boundary:
http://mpa.itc.it/radim/texas.png

For next occasions and others:
m.in.e00 input=st99_d00.e00 action=vector
v.support -r map=st99_d00 err=err
v.out.ascii input=err output=err

dig_ascii/err:
A  2
 26.25857424  -98.6253
 26.25219177  -98.6253

and it is also in st99_d00.e00:
      2094     12234      2039      2040       196       196         2
-9.86252999999997E+01 2.62585742374075E+01
-9.86252999999975E+01 2.62521917668542E+01

so the problem is in st99_d00.e00. I think that such dangles are
allowed in Arc/Info, but as it is not present in st99_d00.shp.
I consider it to be an error in data. You can write to census.gov.

Solution:
v.rm.dangles input=st99_d00 output=us
cp dig_att/st99_d00 dig_att/us
cp dig_cats/st99_d00.name dig_cats/us
v.support -r map=us

d.what.vect ->
-98.94589247(E) 32.37349011(N)
us in us  Area - Category 196 Texas


Radim