[GRASS-user] gshhstograss.c

[Hamish]

NOAA GSHHS coastline data (see the v.in.gshhs module in GRASS 5.4)

Hamish:
> > I successfully imported them just a few weeks ago. Download the
> > shapefile versions and load them with v.in.ogr.

Seb:
> Thanks, yes, I was also able to import them like that, but failed to
> reproject a subset of the data into UTM.  I used v.in.ogr to create a
> new location with the geographic data, created another location with
> the desired UTM and region settings, and then used v.proj to bring the
> geographic vector to the new location.  I got a very weird result
> (http://members.shaw.ca/sluque/earctic.png).  That's why I thought

[Alaska]

> something might be wrong with the shapefiles, so tried to use the
> gshhstograss program instead.


The UTM projection will only be valid within about 3-4 deg lon outside
of the zone. Data from the other side of the planet will head off into
all sorts of mathematical weirdness. In the lat/lon location use
v.in.region + v.overlay to crop out the region of interest and then
v.proj that into your UTM. Also UTM goes nuts near the poles, so
beware of anything north of 80-84 deg lat.

A much smarter man than myself explains:
 http://lists.maptools.org/pipermail/proj/2005-August/001710.html


If you don't get an answer here, maybe ask on the PROJ.4 mailing list
what an appropriate PROJ-compatible projection for the arctic would be.


Hamish