[GRASS-user] import ascii error + how to build a tin

GRASS GRASS user
1

I am getting an error when importing a .xyz file with the coordinates
of a scene. The only reason i am looking at is the fact that the z value
is negative, and after the field separator (,).
Also, after importing how should i build a surface (TIN) and create a
shaded surface?

Here is the error:
Error reading ascii file:
1499.4708,4314.6574,-1.5260

Thanks,
Ricardo

2

Ricardo Oliveira wrote:

I am getting an error when importing a .xyz file with the coordinates
of a scene. The only reason i am looking at is the fact that the z
value is negative, and after the field separator (,).

..

Here is the error:
Error reading ascii file:
1499.4708,4314.6574,-1.5260

what are the v.in.ascii command line options you are using?
what version of GRASS?
fs=, ?

why format=standard not format=point? If using format=standard you need
to use the special format described in the v.in.ascii help page.

it should look like:

v.in.ascii in=points.txt out=new_map x=1 y=2 z=3 -z fs=, format=point

Also, after importing how should i build a surface (TIN)

Look at the v.surf.* modules. (technically a raster surface not a TIN)

and create a shaded surface?

r.shaded.relief or NVIZ.

Hamish

3

Hamish wrote:

Ricardo Oliveira wrote:

Also, after importing how should i build a surface (TIN)

Look at the v.surf.* modules. (technically a raster surface not a TIN)

One can create a raster surface which will look the same as the
rasterised TIN with r.surf.nnbathy from GRASS WIKI raster AddOns site
[1]. Use alg=l for that. See the manual provided in the zip file for
details.

[1]http://grass.gdf-hannover.de/wiki/GRASS_AddOns

Maciek

4

You may want to build a TIN for other reasons, but (unlike ArcGIS) you don¹t
need it in GRASS for displaying shaded relief maps and 2.5 (or even 3D)
maps.

There is a shaded relief module (r.shaded.relief) that runs directly from a
raster map. You can get 2.5-4D displays in NVIZ directly from rasters and
volumes (and 3D vectors too) without making a TIN.

Michael

On 5/22/07 10:19 AM, "Ricardo Oliveira" <autopilot@oniduo.pt> wrote:

I am getting an error when importing a .xyz file with the coordinates
of a scene. The only reason i am looking at is the fact that the z value
is negative, and after the field separator (,).
Also, after importing how should i build a surface (TIN) and create a
shaded surface?

Here is the error:
Error reading ascii file:
1499.4708,4314.6574,-1.5260

Thanks,
Ricardo

__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton