importing vectors

Tim Szeliga tim at
Tue Aug 10 17:08:12 EDT 1993

> I work with lat-lon coordinate files.  I have been successful in importing
> both raster and site data into GRASS with the lat-lon coordinate system.
> The problem is in getting my vector files (state, country borders, rivers,...)
> into GRASS.  I've looked at the output of v.out.ascii and tried mimicing
> its format but all I get is nothing in the vector binary file and 
> dumps  <?? latvalue lonvalue> to the screen for all of my 30,000+
> points in my line segments.

Write a {perl,awk,c,emacs} program to shift each lat/lon pair over one column.
Leave column 1 open with a space.

While I have the lists attention:
 I'm importing the USGS Lakes and Streams DLG datasets into Grass.
When done, (adding cr/lf where appropriate), there are vector
programs to run - 
   v.clean  -  remove dead lines
   v.proj   -  convert the Albers to Lat/Lon
   v.patch  -  merge vector sets
   v.prune  -  thin vector lines by removing points
   v.spag   -  rationalize haphazard digitization
   v.trim   -  trim short lines and spurs

In what order should these be run?  What are suitable values?
The original data is 1:200000, but will be used with 30-arc-sec
DEM on a fairly small scale.  v.prune moves the data too much 
to use for hydrologic modeling.   Any thoughts?

Tim Szeliga tim at CURRENTLY READING - "Forty-Seventeen"
It's a rather pleasant experience to be alone in a bank at night.
                        Willie Sutton

More information about the grass-user mailing list