[OGDev] force_wgs84, Helmert & deps

[Dominic Hargreaves]

On Sat, Oct 28, 2006 at 06:18:09PM +0100, Paul Makepeace wrote:
> I currently have t/53 failing due to WGS84 coords not being
> calculated. I traced this back to Geo::HelmertTransform failing due to
> it not being installed.
> 
> I was going to patch this but wanted to check first. My initial
> thought was if the force_wgs84 param is set to 0 (no) during perl
> Build.PL then the Geo::HelmertTransform requirement should be added to
> the build requires section. Something ditto for
> Geography::NationalGrid::(IE|GB). What say ye?

Hrm, given this is guide-specific rather than installation specific I
would rather fix the test so that it doesn't fail, and then make sure
that a nice run-time error happens when Geo::HelmertTransform is needed
but not installed.

> Also, I'd like to see $@ tested after the transformation; I have that
> as a die in my local source right now. It's at the least irritating
> having silent failures requiring source spelunking.

Nick, any, chance you could look at this bit of it?

> As an aside it made me wonder whether force_wgs84 = 1 is a more
> appropriate default given that it doesn't seem to matter much, and
> it's an optimisation away from performing the transform. I really
> havent looked at the code all that much though so this might not be a
> sensible comment.

Hrm. Not so sure about this really. It does make a difference of about
20 or 30 metres and in towns this is very noticable.

Dominic.

-- 
Dominic Hargreaves | http://www.larted.org.uk/~dom/
PGP key 5178E2A5 from the.earth.li (keyserver,web,email)