[GRASSLIST:1775] Re: zoom to extents, gps device, v.in.shape attribute fields

Hamish hamish_nospam at yahoo.com
Sun Nov 16 21:28:53 EST 2003

> >> On another import of shp files it asks for the label and attribute
> >> fields. When I use fields from dumping on import, regardless of
> >> combination, when I use the query with mouse, no specific data
> >> shows up. Where do I find the name of these fields?
> >
> > v.in.shape -d
> > ?
> I have already been using v.in.shape -d but to add the link between
> mouse query and results what fields do I use?
> v.in.shape -d county.dbf
> Attribute fields available in county.dbf:
> 1: AREA [float4:18]
> 2: PERIMETER [float4:18]
> 3: COUNTY_ [int8:11]
> 4: COUNTY_ID [int8:11]
> 5: FIPS [int4:2]
> 6: NAME [text:12]
> 7: COUNTYNUMB [int4:2]
> v.in.shape -o -d input=county.shp output=county attribute=? label=?

the attribute= field will be used as the category number, the label= as
the text label.

A d.what.vect mouse query will display both category and label

If you want anything more complicated or access to multiple attributes,
you'll have to use the experimental 5.7 version of GRASS, which is
worlds better at dealing with vector data.

> Thanks for the mouse pan-zoom help hamish, it worked, is there a zoom
> to extents?

g.region vector=...

> Havent tried the line of site yet, presumeably I would need some sort
> of topology/elevation vector map to run that query in?

Correct. r.los isn't the greatest, but it works ok as long as you keep
the number of raster cells on the small side. If you want to try the
more advanced r.cva (cumulative viewshed analysis), you'll need to
download and compile it yourself.
see http://grass.ibiblio.org/grass_addons.html

> A garmin gps unit will be my best purchase for gathering site data?
> Any model recomended?

Depends on what sort of accuracy you're looking for and what you mean by
'best'. A Garmin handheld will give you within 3-10m, +/-. A
proper survey-grade Trimble setup will give you position within mm's,
but cost a whole lot more. I've used Garmin 12's & 48's with gpstrans
and that's worked well for me..

> My current mapset and location uses
> zone: 10 South Hemisphere
> projection: utm
> datum: nad83
> ellipsoid: grs80
> but I want to import some data that is in
> Lambert Conformal Conic how to do this without creating another mapset
> or changing the above settings.

The prescribed GRASS way of doing this is to make a new location &
mapset in the "from" projection (ie lcc), import the data into GRASS,
exit GRASS & restart in your target location (ie UTM) & mapset, and then
use [svr].proj. If it is just a text file with x,y,name you might also
try proj.4's cs2cs or GRASS 5.3's m.proj2. If you need to do a datum
transform you'll need to use GRASS 5.3+ or cs2cs. 5.3's "m.proj2 -i" is
useful for converting wgs84 L/L data into your current working
projection (e.g. positions from a GPS).


generally, the GRASS 5.0 tutorial may have some more answers:


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