[GRASS-user] shapefile, TIGER, or what for a dlg that is stored in .e00 format

[Dylan Beaudette]

On Wed, Jul 8, 2009 at 10:17 PM, Hamish<hamish_b at yahoo.com> wrote:
>
>> stephen sefick wrote:
>> > I am trying to make a DEM from contour lines downloaded from here
>> > http://csat.er.usgs.gov/statewide/layers/contours.html
>
> fwiw, v.in.ogr's SDTS driver might help to import DLGs more directly.
> ??
>
>
> Nikos wrote:
>> Perhaps you do not even need to rasterise. Have a look at v.surf.rst
>> [2]. Of course I am no expert with DEM's, v.surf.rst might not be what
>> you need.
>
> v.surf.rst does not do all that well with contour lines. due to the
> adaptive grid size / quadtree design it focuses detail on where the data points are. In this case that's the vertices along the contour lines.
>
> r.surf.contour does a nice job with them though, just read in the help
> page about overcoming the lack of floating-point support, if that is
> needed.
>
>
> also, as mentioned there is probably a higher resolution DEM already out
> there for free, e.g. SRTM 1" (~30m) resolution or USGS quads.

Right. On the seamless.usgs.gov server you should be able to get the
most recent 10m resolution DEM for free in GeoTiff or Arc Grid format.

Cheers,
Dylan