[GRASS-user] Leics: No display in Map Display 1

[Glynn Clements]

> H.S.Rai wrote:

> > On using GRASS 6.2.2, for leics data (probably which is for
> > GRASS 5.2),

Actually, it's 4.2. Yeah, it's old.

Hamish wrote:

> Looking in the leics DEFAULT_WIND, WIND and cellhd/* files I see that
> the proj: listed there is "1", which include/gis.h tells us is
> PROJECTION_UTM. (nb. those files report "zone: 0" while UTM starts at
> 1; UK is in zone 30)

I think that may be a historical artifact, from the time before
PROJECTION_OTHER existed.

> I am not sure what projection is used. Maybe someone who lives close
> to Leicestershire knows. The extents look like:
> 
> north:      322000
> south:      310000
> east:       456000
> west:       444000
> 
> or perhaps it is something custom?

It's:

# OSGB 1936 / British National Grid
<27700> +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.999601 +x_0=400000 +y_0=-100000 +ellps=airy +units=m +no_defs  <>

The tutorial's introduction (gs_intro.ps) mentions that Loughborough
is at the north of the region. Wikipedia puts Loughborough at 52.7705N 1.2046W,
which is:

$ echo 52.7705N 1.2046W | proj -r +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.999601 +x_0=400000 +y_0=-100000 +ellps=airy +units=m +no_defs
453656.57	319545.52

-- 
Glynn Clements <glynn at gclements.plus.com>